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Campus WWTP Expansion Draft EIR EDAW University of California, Davis 4-1 Environmental Settings, Impacts, and Mitigation Measures

4 ENVIRONMENTAL SETTING, IMPACTS, AND MITIGATION MEASURES

4.0 INTRODUCTION

This section of the Draft EIR presents potential environmental impacts of the proposed UC Davis WWTP Expansion Project. The scope of the analysis and key attributes of the analytical approach are presented below to assist readers in understanding the manner in which the impact analysis has been conducted in this Draft EIR.

The preparation of this Draft EIR was preceded by the Tiered IS for the Campus WWTP Expansion Project (included in Appendix A) which determined that the proposed project could result in environmental impacts to three resource areas identified in the CEQA Environmental Checklist as follows:

< Hydrology and water quality (As noted in Section 1.3, this section addresses the potential “Utilities and Service System” impacts identified in the Tiered IS.)

< Biological resources

< Air quality

This chapter examines each of these topic areas in a separate section, presenting the environmental setting, regulatory setting, standards of significance, methodology of the analysis, impacts of the proposed project on the environment, and proposed measures to mitigate the significant impacts. The environmental setting subsections provide an overview of the existing physical environmental conditions at the time the NOP was issued. Much of this information is incorporated by reference from the LRDP EIR, from which this EIR is tiered. The environmental setting is the environmental baseline to which the proposed project is compared to determine its impacts. The regulatory setting subsections identify the environmental laws and regulations that are relevant to each topical section. They describe required environmental permits and other approvals necessary to implement the proposed project. Standards of significance are identified for each environmental issue. These standards are the thresholds used to determine whether implementing the project would result in a significant environmental impact.

Impacts and feasible mitigation measures are presented, where appropriate, for each environmental issue, and a significance determination is provided at the end of each discussion. For each impact identified in the analysis, significance is expressed as one of three determinations: no impact, less than significant, or significant. A significant impact is defined under CEQA as a substantial adverse change to the environment. Where significant impacts are identified, mitigation measures are provided to reduce or avoid the impact. In cases where the impact would not be reduced to a less-than-significant level by the mitigation, the impact is identified as significant and unavoidable.

EDAW Campus WWTP Expansion Draft EIR Environmental Settings, Impacts, and Mitigation Measures 4-2 University of California, Davis

4.0.1 SCOPE OF THE EIR

4.0.1.1 DEFINITION OF BASELINE

The environmental setting sections describe the baseline physical environmental conditions. Pursuant to CEQA, these generally are the conditions at the time the NOP for this Draft EIR was released, May 2004.

4.0.1.2 DEFINITION OF STUDY AREA

The extent of the environmental setting area evaluated (the study area) differs among resources depending on the locations where impacts would be expected. For example, terrestrial biological impacts resulting from the proposed project are assessed for the immediate WWTP site, whereas potential impacts to fisheries resources in Putah Creek must evaluate a larger area of potential effect that includes the downstream influence of the proposed changes in WWTP discharge capacity.

4.0.1.3 BASIS OF IMPACT ANALYSIS

The analysis of impacts in this Draft EIR is based primarily upon the location and magnitude of effect that is projected to occur as a result of the implementation of the project. Impacts are evaluated in terms of changes because of the project as compared to existing conditions. For each resource area, the conditions that would result from implementation and operation of the project at full capacity are compared to baseline conditions to characterize the change.

4.0.1.4 CUMULATIVE IMPACTS

The CEQA Guidelines, Section 15130, require that an EIR discuss cumulative impacts of a project when the project’s incremental effect is “cumulatively considerable.” According to Section 15065, “cumulatively considerable” means the incremental effects of an individual project are considerable when viewed in connection with the effects of past projects, the effects of other current projects, and effects of probable future projects as defined in Section 15130. Pursuant to Section 15130 of the CEQA Guidelines, “(t)he discussion of cumulative impacts shall reflect the severity of the impacts and their likelihood of occurrence, but the discussion need not provide as great detail as is provided for the effects attributable to the project alone. The discussion should be guided by the standards of practicality and reasonableness, and should focus on the cumulative impacts to which the identified other projects contribute rather than the attributes of other projects which do not contribute to the cumulative impact.”

Mitigation measures are to be developed to reduce the project’s contribution to significant cumulative effects whenever feasible. The CEQA Guidelines acknowledge that sometimes the only feasible method for mitigating or avoiding significant cumulative effects is to adopt ordinances or regulations that apply to all projects that contribute to the cumulative effect. Further, there must be a fair and reasonable relationship between the project’s contribution to a significant effect and its level of mitigation. Also, Section 15130(a)(3) of the CEQA Guidelines states that an EIR may determine that a project’s contribution to a significant cumulative

Campus WWTP Expansion Draft EIR EDAW University of California, Davis 4-3 Environmental Settings, Impacts, and Mitigation Measures

impact will be rendered less than cumulatively considerable, and thus not significant, if a project is required to implement or fund its fair share of a mitigation measure or measures designed to alleviate the cumulative impact.

The 2003 LRDP EIR evaluated the cumulative environmental impacts of campus activities, development of facilities, and population growth that would occur because of growth under the 2003 LRDP through the 2015–2016 academic year together with other regional development. Expansion of the current WWTP facilities was included in the 2003 LRDP and impacts associated with that expansion were evaluated in the LRDP EIR. The campus anticipated that modular expansions of the WWTP treatment process units would be implemented to meet campus demands for wastewater treatment. The proposed project addresses the first phase of the previously anticipated modular expansion to meet campus wastewater treatment demands through 2013. A second phase of the WWTP facilities expansion would be required beyond the improvements addressed in the proposed project to meet wastewater treatment demands for campus growth anticipated through 2015–16 under the LRDP. These additional improvements could include construction of a third sludge storage basin and a fourth drying bed, and potential further expansion of the oxidation ditch. These future changes would increase the average and peak flow rates of treated effluent discharged to Putah Creek, but the quality of water discharged would be expected to be similar to current conditions because there would not be any changes made to the major treatment processes.

The 2003 LRDP EIR fully analyzed the direct and indirect environmental impacts associated with the implementation of the LRDP. Because expansion of the WWTP is part of the 2003 LRDP, the proposed project was included in the cumulative impact evaluation presented in the 2003 LRDP EIR. The cumulative context in the 2003 LRDP EIR varied depending on the nature of the issue being studied. Cumulative effects for the resource areas affected by the proposed project (i.e., biological resources, hydrology and water quality, and air quality) were evaluated with respect to natural resource boundaries. The approach to cumulative impacts used in this Draft EIR is consistent with the cumulative impact analyses approach in the LRDP EIR. At this time, no changes to planned campus projects that were included in the 2003 LRDP, or any other non-campus projects, have been identified that would potentially contribute to related cumulative impacts of the proposed project.

When and if future expansion of the WWTP is determined necessary, the campus will evaluate associated environmental impacts in a separate environmental review process pursuant to the requirements of CEQA. The October 2003 Detailed Project Plan for the proposed WWTP expansion (Brown and Caldwell 2003) provides the most up-to-date evaluation of wastewater treatment demand and necessary upgrades to treatment facilities that are anticipated to be needed through 2017. The anticipated future phase of a modular expansion of WWTP facilities to meet wastewater treatment demands through 2017 is thus addressed in this Draft EIR as a reasonably foreseeable future project.

Campus WWTP Expansion Draft EIR EDAW University of California, Davis 4.1-1 Hydrology and Water Quality

4.1 HYDROLOGY AND WATER QUALITY

4.1.1 INTRODUCTION

As discussed in the Notice of Preparation and Tiered IS for the WWTP Expansion Project (Appendix A), this analysis discusses the potential hydrologic and water quality impacts that would be caused because of the proposed increase in the amount of tertiary-treated effluent discharged from the WWTP to the South Fork of Putah Creek (Putah Creek). In particular, this analysis addresses potential project-specific impacts and cumulative impacts. It also assesses the significance of potential adverse impacts based on applicable thresholds of significance, including water quality objectives and effluent limits for specified pollutants contained in the current NPDES permit for the WWTP that was adopted in January 2003.

4.1.2 ENVIRONMENTAL SETTING

Section 4.8 of the 2003 LRDP EIR provides an extensive description of the hydrologic and water quality environmental setting of the proposed project area (UC Davis campus and surrounding area), and the Tiered IS for the WWTP Expansion Project (Appendix A) further summarizes hydrology and water quality setting information specific to the WWTP project area (pp. 77-81). Information regarding the current WWTP and other permitted campus discharge operations to Putah Creek, the NPDES permit for the WWTP, and recent WWTP compliance history with NPDES permit limits are described in the LRDP EIR (pp. 4.8-24 to 4.8-28). The Tiered IS described the most current information on the WWTP and industrial pretreatment program operations conducted for maintaining compliance with NPDES permit limits (pp. 80-81). Information from these discussions is incorporated by reference and relevant information summarized as follows:

< WWTP Operations for NPDES Permit Compliance: The campus WWTP provides advanced tertiary level treatment by oxidation, sand filtration, and UV disinfection that produces effluent with substantially higher water quality than the previous decommissioned campus WWTP. NPDES permit compliance operations are primarily associated with measures for effluent water quality compliance. Inflow and effluent monitoring is the primary means of controlling WWTP compliance with effluent water quality terms and conditions. WWTP staff have adjusted some monitoring and treatment process protocols in recent years to more effectively detect problems and maintain permit compliance. For instance, more frequent (daily) monitoring has been implemented for copper, along with changes in the types of coagulants used for filtration aids. WWTP staff have also implemented source control and coagulant modifications to provide turbidity control and avoid aluminum discharges that previously had been associated with use of aluminum sulfate as a coagulant.

< Pretreatment Program: The campus operates a pretreatment program to reduce pollutant concentrations and ensure compliance with the NPDES permit. Aspects of the pretreatment program include monitoring, inspection, education, and enforcement. The campus pretreatment program is modified as necessary to respond to changing conditions

EDAW Campus WWTP Expansion Draft EIR Hydrology and Water Quality 4.1-2 University of California, Davis

or specific constituent problems including such measures as: (1) adjusting sewer discharge limits for specific constituents; (2) conducting campus-wide facility audits and source studies to evaluate potential sources of specific constituents; and (3) conducting special studies to evaluate WWTP process control measures that may improve treatment and/or removal of constituents from wastewater.

This Draft EIR provides additional information pertaining to the existing WWTP effluent and Putah Creek (receiving water) water quality conditions immediately upstream and downstream of the campus discharge based on the recent monitoring data collected since March 2000. Data from March 2000 to July 2004 were used for this Draft EIR because they represent the period becaue the current WWTP became operational, the Putah Creek Accord (Accord) that regulates the flows in Putah Creek from Lake Berryessa (as part of the Solano Project) was also enacted in spring 2000. Before the Accord, the stipulated release schedule for water from the Solano Project to lower Putah Creek (i.e., that portion of the river downstream from the Putah Diversion Dam near the community of Winters) was occasionally insufficient during the dry season (i.e., typically April-October) to provide river flow all the way to the Yolo Bypass. During these low-flow periods, much of the water released to the river percolated into the creekbed or was diverted for irrigation use by riparian landowners before it reached the Davis area. The Accord requires water releases that are sufficient to provide surface water flow all the way to the Yolo Bypass, with additional provisions for specific releases to aid fisheries resources. The Accord provides for reduced flow releases only during drought periods; however, active flow of at least 1 cubic foot per second (cfs) must reach at least the Interstate 80 (I-80) bridge during drought periods. Because of these to major changes, WWTP effluent flow and water quality characteristics before March 2000, and summer low-flow period conditions in Putah Creek before 2000, are no longer representative of current conditions. Water quality data from before that period are briefly discussed below but are provided only for contextual purposes.

Table 4.1-1 summarizes water quality measurements recorded from Putah Creek downstream of the WWTP discharge point (sample location R2 approximately 200 feet downstream from the WWTP discharge; refer to Exhibit 3-2) on a weekly basis by WWTP staff for conventional physical and inorganic parameters. The data show the comparative annual mean values for an approximate 4.5-year period (1992-1996) as originally presented in the 1996 Wastewater Treatment Plant Replacement Project EIR; the available data from the current WWTP also covers a 4.5-year duration of monitoring (2000–2004). Data for 1997–1999 have not been compiled; however, the two existing datasets are considered representative and comparable because they include an identical and substantial duration of monitoring with which to assess differences in the data. The data indicate no particularly strong differences in values measured during operations of the previous WWTP and pre-Accord instream flows compared to the current timeframe with the existing WWTP operations and Accord flows.


Table 4.1-1 Putah Creek Water Quality Downstream from WWTP Outfall

Parameter (units) and annual mean values Year

DO (mg/L) pH (standard units) Turbidity (NTU) Temperature (°C)

Measurements from years when previous campus WWTP was operational 1992 8.5 7.7 17.6 19.0 1993 8.4 8.0 16.2 15.5 1994 5.5 7.5 7.3 17.3 1995 6.4 7.9 18.4 16.7

1996 a 8.2 7.4 32.0 15.9 Measurements from years with current campus WWTP

2000 9.7 8.3 18 17.2 2001 8.5 8.2 24 18.3 2002 9.0 8.3 10 18.0 2003 9.1 8.2 19 21.4

2004 a 9.8 8.2 14 16.9 Notes: Sources: 1992 through 1996 data from Jones & Stokes Associates (1996); 2000 through 2004 based on UC Davis discharge monitoring reports (Fan pers. comm.). Both datasets based on the means of the weekly samples. DO = dissolved oxygen mg/L = milligrams per liter NTU = nephelometric turbidity units a Data from January through June only (as reported in the 1996 WWTP Replacement Project EIR; only data available for current WWTP).

Background monitoring data for selected trace metal and organic compounds measured in Putah Creek becaue the current WWTP became operational are described below in Section 4.1.4, Environmental Impacts and Mitigation Measures. In general, concentrations of the U.S. EPA-designated “priority pollutants” trace metal and organic compounds are below regulatory thresholds. Putah Creek below Lake Solano is listed on the state’s 2002 303(d) list of impaired water bodies for mercury (SWRCB 2003). The Total Maximum Daily Load (TMDL) for mercury is identified as a low priority, and the completion dates for development of the TMDL waste load assessment report and supporting implementation plan have not been scheduled.

As described in Chapter 3, Project Description, the campus received its most recent NPDES permit for its discharge to Putah Creek in January 2003, and the amended permit with effluent electrical conductivity (EC) limit and accompanying Cease and Desist Order was issued in March 2004. In general, because the current WWTP became operational in March 2000, the treated wastewater discharges to Putah Creek have generally complied with permit conditions, but have experienced very few and infrequent permit limit exceedances for turbidity, copper, aluminum, total coliform bacteria, chlorine residual, and pH, with no observed or known adverse effects to Putah Creek receiving water quality. As described above regarding the current effluent EC permit limit and Cease and Desist Order, the WWTP currently does not comply with the 900 µmhos/cm limit. Table 4.1-2 shows a comparison of


performance data from the previous WWTP and the current WWTP, and indicates that the current WWTP effluent has considerably lower concentrations of biochemical oxygen demand (BOD) and total suspended solids (TSS) as a result of improved oxidation and filtration processes. Concentrations of effluent pH and EC are notably higher compared to the previous WWTP.

As part of the NPDES permit renewal process, the RWQCB conducted an analysis in 2002 to determine which pollutants contained in the campus WWTP effluent had a reasonable potential to cause or contribute to a violation of water quality standards in Putah Creek. Background monitoring data for selected trace metal and organic compounds measured in the current WWTP are described below in Section 4.1.4, Environmental Impacts and Mitigation Measures. The analysis for potential compliance led to the current Cease and Desist Order for the WWTP for constituents including copper, cyanide, nitrate + nitrite, iron, and EC. The permit also identified a number of constituents that were not detected at detection limits that exceed the criterion concentration. To determine if WWTP effluent may cause or contribute to an exceedance of these criteria, the campus is being required to continue monitoring for those constituents on a regular basis.

Table 4.1-2 Summary of WWTP Effluent Monitoring Results for Conventional Parameters

Measurements (mean) from years when previous campus WWTP was operational Parameter a (units)

1992 1993 1994 1995 1996 b BOD (mg/L) 5.0 6.0 7.0 6.0 8.3 TSS (mg/L) 5.0 6.0 5.5 8.0 9.8

EC (µmhos/cm) 988 972 933 892 778 pH (standard units) 7.3 7.2 7.0 7.1 6.8

Flow (mgd) 1.58 1.64 1.45 1.56 1.66 Measurements (mean) from years with current campus WWTP

Parameter (units) 2000 2001 2002 2003 2004 b

BOD (mg/L) 1.7 1.2 0.9 1.4 1.3 TSS (mg/L) 1.6 1.2 1.2 0.9 0.7

Ammonia (mg/L-N) 0.27 0.09 0.23 <0.5 <0.5 EC (µmhos/cm) 970 1070 1080 1080 1080

pH (standard units) 7.9 8.0 8.0 8.0 8.0 Temperature (°C) 22.2 22.2 21.6 21.7 21.8

Flow (mgd) 1.72 1.54 1.64 1.63 1.9 Notes: Sources: 1992 through 1996 data from Jones & Stokes Associates (1996); 2000 through 2004 based on UC Davis discharge monitoring reports (Fan pers. comm.) Both datasets based on similar sampling protocols – frequency of sampling varies depending on the constituent. BOD = biochemical oxygen demand mg/L = milligrams per liter TSS = total suspended solids EC = electrical conductivity a Ammonia and temperature data not included in the source table in the 1996 WWTP Replacement Project EIR. b Data from January through June only (as reported in the 1996 WWTP Replacement Project EIR; only data available for current WWTP).


4.1.3 REGULATORY SETTING

Section 4.8.1.6 (pp. 4.8-20 to 4.8-24) of the 2003 LRDP EIR and the Tiered IS (pp. 79-81) provide relevant information regarding the regulatory setting for the current WWTP discharge to Putah Creek and are incorporated by reference in this Draft EIR. In summary, the federal Clean Water Act (CWA), federal Safe Drinking Water Act , state Poter-Cologne Water Quality Control Act and associated Title 23 water quality provisions of the California Water Code (California Code of Regulations [CCR], Section 13000 et seq.), and Title 22 wastewater reclamation guidelines of the California Health and Safety Code (CCR, Section 60301 et seq.) establish the primary policies for water quality protection in California and are implemented by the State Water Resources Control Board (SWRCB) and nine RWQCBs. The applicable water quality standards of the National Toxics Rule (NTR), the California Toxics Rule (CTR), the Central Valley RWQCB Basin Plan water quality objectives, drinking water standards (i.e., Maximum Contaminant Levels [MCLs]), U.S. EPA national recommended water quality criteria, and supporting guidance policies (e.g., Basin Plan, State Implementation Policy (SIP) for toxic substances, state and federal anti-degradation policies) that apply to the WWTP discharge and Putah Creek are identified in the analysis below. The NTR/CTR established the applicable ambient water quality criteria for toxic trace metals and organic compounds for inland surface waters and estuaries of California. The SIP established a standardized approach for NPDES permitting discharges of toxic contaminants, and in combination with watershed management approaches and TMDL programs, are used by the RWQCB to ensure achievement of the water quality standards that are intended to protect human health and aquatic life. The SWRCB antidegradation policy (Resolution 68-16) consists of two goals for existing high quality waters in the State: (1) maintain existing high quality water until it has been demonstrated to the State that any change will be consistent with maximum benefit to the State and will not unreasonably affect present and anticipated beneficial use of such water; and (2) discharges to existing high quality waters will be required to meet waste discharge requirements which will result in the best practicable treatment or control of the discharge necessary to assure that highest water quality consistent with maximum benefit to the State will be maintained.

Water quality objectives (i.e., narrative and numerical water quality criteria) are established in the RWQCB Basin Plan to protect the established beneficial uses of surface water and groundwater. For municipal wastewater treatment plants, the RWQCB implements the Basin Plan primarily by imposing waste discharge requirements (WDRs), NPDES permits, and wastewater reclamation (i.e., recycling) requirements to ensure that waste discharges comply with established regulatory policies, procedures, and water quality criteria. Putah Creek has designated existing beneficial uses from Lake Berryessa to its terminus at the Yolo Bypass that include municipal, industrial, and agricultural water supply; contact and noncontact recreation; warm freshwater habitat; and wildlife habitat. The Basin Plan identifies cold freshwater habitat as a potential beneficial use. Although municipal and industrial water supply is a designated beneficial use, DHS has identified that there are no permitted public water supply systems utilizing lower Putah Creek as source water for drinking water downstream from the WWTP discharge (Phillips pers. comm.).


4.1.4 ENVIRONMENTAL IMPACTS AND MITIGATION MEASURES

4.1.4.1 STANDARDS OF SIGNIFICANCE

For this analysis, the standards of significance used in the 2003 LRDP EIR will be utilized. As such, an impact is considered significant if the project would:

< Violate any water quality standards or waste discharge requirements.

< Substantially deplete groundwater supplies or interfere substantially with groundwater recharge such that there would be a net deficit in aquifer volume or a lowering of the local groundwater table level.

< Substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river, or substantially increase the rate or amount of surface runoff in a manner that would result in flooding on site or off site.

< Create or contribute runoff water that would exceed the capacity of existing or planned stormwater drainage systems or provide substantial additional sources of polluted runoff.

< Otherwise substantially degrade water quality.

< Place in a 100-year flood hazard area a structure that would impede or redirect flood flows.

< Expose people or structures to a significant risk of loss, injury, or death involving flooding.

Impacts Adequately Analyzed in the LRDP EIR or Impacts Not Applicable to the Project

The Tiered IS for the WWTP Expansion Project (Appendix A), relying in part on Section 4.8 of the 2003 LRDP EIR, addresses and eliminates from analysis some of the standards of significance identified above. In particular, the Tiered IS identified that the following potential project-related impacts would either not occur, or would be less-than-significant: impact the recharge capacity of groundwater aquifers; exceed the capacity of an existing or planned stormwater drainage system; be located or include housing in a 100-year flood zone; create a flood hazard or be subject to risk of flooding as a result of a dam failure; and subject to inundation by seiche, tsunami, or mudflow.

4.1.4.2 IMPACT ASSESSMENT METHODS

To determine if the proposed project would have a significant impact on water quality by violating any water quality standards or waste discharge requirements, or otherwise substantially degrade water quality, several different analyses were conducted using background receiving water and effluent water quality data to predict the change in downstream water quality. The analyses were conducted on the “priority parameters,” which are defined herein to include the parameters with permit limits contained in the NPDES


permit for the WWTP, as well as 303(d)-listed parameters (mercury). The priority parameters are listed in Table 4.1-3.

Table 4.1-3. Priority Parameters

Aluminum Temperature

Ammonia Nitrate + Nitrite

Arsenic pH

Copper Phosphorus

Cyanide Electrical Conductivity

Dichloromethane Total Coliform

Dioxin Residual Chlorine

Iron Toxicity

Lead Turbidity

Mercury

In addition to the parameters listed in Table 4.1-3, this EIR also evaluates endocrine disruptor compounds, or EDCs. EDCs and their potential environmental effects are not regulated per se, however, there are some specific compounds that are known or suspected EDCs that are regulated in surface water or drinking water to minimize the general toxicity effects that they are known to produce. EDCs are not regulated in the NPDES permit for the WWTP, nor is it a 303(d)-listed parameter. However, EDCs were raised as an issue in an NOP comment letter (see Appendix A) and are therefore being considered herein.

To perform the portion of the analysis that predicts downstream receiving water concentrations at the various discharge flow rates, a consistent and recent dataset for Putah Creek upstream of the WWTP discharge and the WWTP effluent was needed. The most recent dataset available that covered all of the priority parameters of concern was from 2002 when the WWTP staff conducted a year-long monitoring special study for a full suite of inorganic and organic constituents in both the effluent and receiving water as required by the RWQCB for the purpose of determining the constituents that had a reasonable potential to exceed applicable regulatory criteria (Fan, pers. comm., 2004). With the exception of EDCs, Section 4.1 does not address further constituents that were not found to have a reasonable potential to exceed criteria. Dissolved oxygen, temperature, and toxicity primarily affect fisheries and other aquatic organisms and, therefore, are addressed in the “Aquatic Resources” assessment included in Section 4.2.

An additional step was taken to determine if 2002 was a representative year for the receiving water and WWTP effluent. In this step, an evaluation of concentration fluctuations from year-to-year was performed. Using concentrations of EC from the 2000–2004 dataset, it was determined that 2002 receiving water data would provide an adequate representation of pollutant concentrations for this analysis (Exhibit 4.1-1). While there was some variation between different years’ monthly EC concentrations in the receiving water and the effluent, the

Campus WWTP Expansion Project P 4T041.01 07/04

Source: Larry Walker Associates 2004 (based on UC Davis WWTP Data)

800

0

200

400

600

1000

1200

1400

um

ho

s/cm

Monthly Average Electrical Conductivity (March 2000 – July 2004) 4.1-1 EXHIBIT

2000

2001

2002

2003

2004

1180

1097

1077

1130

Effluent

493

523

446

Upstream Monitoring Station (R1)

575

549

505

Downstream Monitoring Station (R2)

528

510 1070

589

468



main focus of this analysis is to evaluate the project-related changes in receiving water concentrations resulting from increasing the effluent flow. Using any of the 4 years of available monitoring data allows a reasonably representative evaluation of predicted incremental changes to water quality under the proposed project. The benefit of using 2002 data is that of the 4 years examined, it represents the largest and most consistent dataset for more parameters.

Permit Compliance Analysis

Summarized self-monitoring data for the WWTP effluent for the 2000–2004 period are tabulated in Table 4.1-4. The data are described in the pollutant-by-pollutant discussion provided later. Table 4.1-5 shows the comparable summarized 2002-only WWTP effluent dataset. To determine if the proposed project would violate current NPDES permit limits, current mean and maximum effluent concentrations, as calculated from the 2000–2004 dataset, were compared to the applicable regulatory criteria for most priority pollutants. In some cases, more recent data were relied upon instead of the entire 2000–2004 dataset because of recent changes in operation of the campus WWTP. In particular, the more recent data are used for copper, aluminum, and turbidity because the WWTP staff have adjusted monitoring and/or procedures for adding filtration coagulant that have demonstrated improved reliability at maintaining compliance with regulatory criteria. Since the level of treatment at the WWTP would remain the same after expansion, the concentration levels of the priority pollutants are not expected to change, except for those affected by the changes in WWTP operations. Additionally, the campus does not receive dilution credits based on the flow of Putah Creek to determine if the effluent would cause or contribute to the violation of a water quality standard. As a result, water quality criteria are applied as permit limit concentrations to the undiluted WWTP effluent (i.e., evaluated on an “end-of-pipe” basis). This application of criteria at the end-of-pipe reflects the worst case and rare condition of zero flow in Putah Creek. Moreover, the analysis of end-of-pipe effluent values is equivalent to an analysis of receiving water quality effects (described below) should a zero flow condition occur over a limited period of time in Lower Putah Creek in the future because of drought.

The monitoring required by the RWQCB for toxic constituents during 2002 resulted in a list of specific constituents that went undetected but had detection limits greater than applicable criteria. The list of constituents is shown in Table 4.1-6. The RWQCB requires the WWTP to continue annual monitoring for these parameters, however, they are not addressed further in this analysis because the data are not sufficient to evaluate compliance with applicable criteria.


Table 4.1-4 WWTP Effluent Water Quality Summary (March 2000 – June 2004)

Results in µg/L unless stated otherwise Parameter Effluent Limit 1

n 2 No. Detected 3 Mean Median Min 4 Max

Aluminum 87 42 42 40 35 9.56 251 Ammonia (mg/L-N) 1.96 a 479 330 0.17 0.09 0.01 1.56 Arsenic NA 14 14 5.2 5.1 4 7.7 Chlorine, Residual (mg/L) 0.01 339 1 - - <0.02 2.25 b Chromium, Total 50 21 15 2.9 2.5 1.9 6.4 Copper 9.7 c 61 50 10.8 7.8 2.5 71.2 Cyanide 5.2 44 2 - - 19 21 Dichloromethane 4.7 31 3 - - 0.6 1.9 Dioxin (pg/L) 0.014 31 1 - - <25 12 e EC (µmhos/cm) 900 846 846 1135 1091 686 4610 Hardness (mg/L CaCO3) NA 38 38 178 175 110 367 Iron 300 12 12 72 45 21 445 Lead 3.6 c 19 4 0.7 0.2 0.2 7.4 f Mercury NA 12 12 0.004 0.002 0.0002 0.02 Nitrate + Nitrite (mg/L-N) 10 31 31 12 9 3 104 f pH (standard units) 6.5-8.5 1045 1045 8 8 6.5 8.7 Phosphorus, Total (mg/L-P) NA 18 18 3.1 3.0 1.1 4.5 Temperature (°C) NA 1045 1045 21.9 21.7 8.0 34.8 f Total Coliform (MPN/100 ml) 2.2 84 84 9 4 2 240 Turbidity (NTU) 2 d 858 858 0.6 0.5 0.1 9.2 Source: Larry Walker Associates based on UC Davis WWTP discharge monitoring data. 1. Lowest limit in current UC Davis NPDES permit (Note: per permit conditions, some effluent limits are calculated based on effluent hardness and pH values). 2. Number of samples analyzed. 3. Number of samples where the constituent was detected above the laboratory’s analytical reporting limits (i.e., lowest quantifiable concentration). 4. Min = minimum value detected, or lowest reporting limit if none detected. a. Calculated effluent limit based on pH - minimum calculated criterion shown based on maximum pH of 8.2 b.Single value exceeded criteria during a filter cleaning operation. Routine WWTP operations do not use chlorine for disinfection. Cleaning procedure has been adjusted and approved by RWQCB to recycle rinsate from cleaning operation back into the wastewater treatment processes. c. CTR criteria based on minimum hardness of 110 mg/L d Daily average turbidity limit. Turbidity also cannot exceed 5 NTU more than 5 percent of time; instantaneous maximum limit of 10 NTU. e. Estimated value - analyte was detected but concentration was lower than laboratory reporting limit. f. Apparent outlier value - = insufficient number of samples with detection of constituent to calculate summary statistics for mean and median pg/L = picograms per liter NA = Not Applicable – current UC Davis NPDES permit does not contain a permit limit for the constituent. MPN/100 ml = most probable number per 100 milliliters


Table 4.1-5 WWTP Effluent Water Quality Summary for 2002

Results in µg/L unless stated otherwise Parameter

Mean Median Min Max

Aluminum 23 23 10 41

Ammonia (mg/L-N) 0.23 0.14 0.10 0.87

Arsenic 5.1 4.9 4.0 7.7

Chromium, Total 3.57 3.30 1.86 6.40

Copper 9.0 6.4 4.2 29.3

Cyanide - - 19 19

Dichloromethane - - <2 <2

Dioxin (pg/L) - - <25 12

EC (µmhos/cm) 1097 1078 1009 1373

Hardness (mg/L CaCO3) 191 183 110 367

Iron 72 43.0 20.8 445

Lead 3.79 3.8 0.15 7.42

Mercury 0.004 0.002 0.0002 0.021

Nitrate + Nitrite (mg/L-N) 19 9 5 104

pH (standard units) 7.9 7.9 7.5 8.0

Phosphorus, Total (mg/L) 3.075 3.15 1.8 4.3

Temperature (°C) 21.8 22.4 13.3 25.6

Total Dissolved Solids (mg/L) 573 582 504 615

Turbidity (NTU) 0.6 0.5 0.4 1.6 Source: Larry Walker Associates based on UC Davis WWTP discharge monitoring data.

Impact on Putah Creek Downstream of Discharge Analysis

2002 Flow Conditions Analysis: The proposed project would expand the current permitted ADWF design capacity of the WWTP from 2.7 mgd to 3.8 mgd. Although the existing permitted capacity would allow the WWTP to continue to increase the discharge up to 2.7 mgd, the CEQA baseline (i.e., “existing”) condition is the current ADWF of 1.7 mgd. To determine if the proposed project would adversely affect Putah Creek water quality conditions downstream of the WWTP discharge point, two different questions must be answered. First, assuming complete mixing of the WWTP effluent and the receiving water, would the downstream concentration of Putah Creek exceed applicable water quality objectives if the WWTP discharge were increased to 3.8 mgd? Second, again assuming complete mixing, would the increase in the WWTP permitted design capacity from 2.7 mgd to 3.8 mgd potentially violate the state and federal antidegradation policies? The RWQCB standard procedure is to consider project-related compliance with antidegradation policy based on changes to permitted design capacity.


Table 4.1-6 WWTP Effluent Data (2002-2004) for Non-Detected Parameters in NPDES Permit (Finding 27)

Parameter Water Quality Criteria (CTR)

(µg/L) Maximum Detected Value

(µg/L) 1,1,2,2-Tetrachloroethane 0.17 ND 1,1-Dichloroethane NA ND 1,2-Dichloroethane 0.38 ND 1,2-Diphenylhydrazine 0.04 ND 2,4,6-Trichlorophenol 2.1 ND 2,4-Dichlorophenol 93 ND 2,4-Dinitrotoluene 0.11 ND 2,6-Dinitrotoluene - ND 2-Chlorophenol 120 ND 3,3 Dichlorobenzidine 0.077 ND 4,4'-DDD 0.00083 ND 4,4'-DDE 0.00059 ND 4,4'-DDT 0.00059 ND Acrylonitrile 0.059 ND Aldrin 0.00013 ND Atrizine - ND Benzidine 0.00012 ND Benzo(k)Fluoranthene 0.0044 ND Bis(2-Chloroethyl)Ether 0.031 ND Cadmium 2.65 ND Carbon Tetrachloride 0.25 ND Chlordane 0.00057 ND Chlorpyrifos - ND Dibromochloropropane (DBCP) - ND Diazinon - ND Dichlorobromomethane 0.56 ND Diquat - ND Ethylene dibromide - ND Heptachlor 0.00021 ND Heptachlor Epoxide 0.0001 ND Hexachlorobenzene 0.00075 ND Hexachlorocyclopentadiene 240 ND Indeno(1,2,3-cd)Pyrene 0.0044 ND N-Nitrosodimethylamine 0.00069 ND N-Nitrosodi-n-Propylamine 0.005 ND Polychlorinated biphenyls (sum of 7) 0.00017 ND Toxaphene 0.00073 ND Source: Larry Walker Associates based on UC Davis WWTP discharge monitoring data. ND = not detected


To answer these questions, chemical concentrations for individual constituents in Putah Creek downstream of the discharge were estimated by a mass balance calculation using upstream receiving water (sample location R1 approximately 30 feet upstream from the WWTP discharge; refer to Exhibit 3-2) and effluent concentrations, and mean monthly receiving water and effluent flows. The receiving water quality concentrations projected with the mass-balance approach were compared to the lowest applicable regulatory water quality criteria for impact assessment. Applicable regulatory criteria that depend on hardness and pH were calculated based on the blended mix of wastewater and background Putah Creek receiving water. The monthly self-monitoring results of 2002 for the upstream monitoring station (labeled R1) and WWTP effluent concentrations were used for the mass balance model.

The mean monthly effluent discharge rate and mean daily Putah Creek flow that correspond to the day of the sample collection event, were used for the flow inputs to the mass-balance analysis under 2002 conditions and are considered representative of a typical year with background streamflow available under the terms of the Accord. Background Putah Creek streamflow at the I-80 flow gauge ranged from a mean daily flow of 54 cfs in April 2002 to a low flow of 8 cfs during October 2002 when the water quality sample dataset was collected. Available constituent concentration data for receiving water from 2000 to 2004 at station R1 upstream from the WWTP discharge outfall is summarized in Table 4.1-7. Table 4.1-8 shows the comparable data summarized for the 2002-only dataset.

By applying the following mass balance equation, it was possible to calculate predicted downstream concentrations using effluent and upstream concentrations and flows:

Arranging this equation yields the following equation for calculating downstream concentrations. This equation was then used to estimate concentrations downstream of the effluent discharge.


Table 4.1-7 Upstream Putah Creek (R1) Water Quality Summary (March 2000 – June 2004)

Results in µg/L unless stated otherwise 2 Parameter Criteria 1

n 3 No. Detected 4 Mean Median Min 5 Max

Aluminum 87 a 12 12 158 116 34 526 Ammonia (mg/L-N) 0.35 b 12 10 0.11 0.12 0.1 0.2 Arsenic 10 c 12 12 1.71 1.62 0.76 2.74 Chlorine, Residual (mg/L) 0.01 35 0 - i - i <0.02 <0.02 Chromium, Total 238 d 12 12 5 4 1 14 Copper 10.4 d 12 12 1.9 1.6 0.8 6.0 Cyanide 5.2 e 12 1 - i - i - 6.7 Dichloromethane 4.7 e - - - i - i <2 35 Dioxin (pg/L) 0.013 e 5 3 18 29 12.6 56 Dissolved Oxygen (mg/L) 5 f 192 192 9 9 6 16 EC (µmhos/cm) 900 c 253 253 486 476 180 735 Fecal Coliform (MPN/100 mL) 200 f 55 55 128 29 4 2347 Hardenss (mg/L CaCO3) NA 72 72 229 208 69 1400 Iron 300 c, g 12 12 266 j 203 j 79 j 988 j Lead 3.0 d 12 2 0.23 0.66 0.66 2.1 Mercury 0.05 e 12 12 0.007 0.002 0.00004 0.030 Nitrate + Nitrite (mg/L-N) 10 c 12 12 4.4 2.3 1.0 23 k pH (standard units) 6.5-8.5 f 194 194 8.2 8.2 7.6 8.9 Phosphorus, Total (mg/L-P) NA 12 3 0.075 0.075 0.02 0.14 Temperature (°C) h 194 194 17.2 16.3 7.2 36.1 k Turbidity (NTU) h 107 107 14.6 8.2 1.1 213 Source: Larry Walker Associates based on UC Davis WWTP discharge monitoring data. 1. Lowest calculated effluent limits based on applicable criteria for given receiving water hardness and pH values. 2. Metals analyzed as total recoverable concentration 3. Number of samples analyzed. 4. Number of samples where the constituent was detected above reporting limits. 5. Min = minimum value detected, or lowest reporting limit if none detected a. 2002 USEPA Ambient Criteria b. EPA Ambient Water Quality Report, minimum criterion based on maximum pH of 8.9 c. State and Federal drinking water MCLs d. CTR minimum criterion based on statistically calculated low hardness of 119 mg/L (99th percentile) e. CTR human health criteria. f. Basin Plan g. Applicable Water Quality Standard is in dissolved form h. Basin Plan - numerical objective for allowable change from background i. - = insufficient number of samples with detection of constituent to calculate summary statistics for mean and median. j. Samples analyzed as total recoverable concentration k. Apparent outlier value. NA = No applicable regulatory criteria.


Table 4.1-8 Upstream Putah Creek (R1) Water Quality Summary for 2002

Results in µg/L unless stated otherwise Parameter

Mean Median Min Max

Aluminum 158 135 34 526

Ammonia (mg/L-N) 0.11 0.12 0.1 0.20

Arsenic 1.7 1.6 0.8 2.7

Chromium, Total 4.8 4.06 1.03 14.1

Copper 1.9 1.6 0.8 6.0

Cyanide - - 6.7 6.7

Dichloromethane - - 35 35

Dioxin (pg/L) 34 34 12.6 55.9

EC (µmhos/cm) 523 493 460 637

Hardness (mg/L CaCO3) 244 206 148 609

Iron 266 190 79 988

Lead 1.38 1.38 0.66 2.1

Mercury 0.007 0.002 0.00004 0.030

Nitrate + Nitrite (mg/L-N) 4 2 0.96 23

pH (standard units) 8.3 8.3 7.8 8.6

Phosphorus, Total (mg/L-P) 0.07 0.07 0.01 0.14

Temperature (°C) 17.6 18.65 11.4 23.7

Total Dissolved Solids (mg/L) 303 292 246 384

Turbidity (NTU) 20 11 2 83

Source: Larry Walker Associates based on UC Davis WWTP discharge monitoring data.

The mass balance tool assumes that all parameters are conservative (i.e., no decay occurs in the time and space boundaries of the analysis). It also assumes that the WWTP effluent concentrations for the priority parameters would not change markedly from the concentrations found in 2002. This assumption is sound because the expansion would increase the capacity of the treatment facility while maintaining the same level of treatment currently in operation. In a few instances where recent changes in operation of the facility or influent concentrations may have an impact on the priority pollutant concentration as compared to the 2002 concentration level, those impacts are discussed further and more recent data are used to determine effects to the receiving water.

An analysis of the future expansion to 4.3 mgd (i.e., by 2017) is discussed in the cumulative section as a reasonably anticipated future expansion of the WWTP’s permitted ADWF design capacity, as is indicated in the 2003 LRDP and Chapter 1, Introduction.


Worst Case No-Flow Putah Creek Analysis: The worst case analysis assumes the projected WWTP effluent quality conditions with no background flow in Putah Creek, because, for that analysis, the effluent is assumed to be the only contributor to flow in the reach of Putah Creek from the WWTP discharge downstream to the Yolo Bypass. The expected future frequency of zero flow in Putah Creek is unknown given the recent passage of the Accord in 2000 that effectively creates new operating instream flow conditions in lower Putah Creek. However, the probability of zero flow in the channel has decreased considerably compared to prior instream flow requirements because the Bureau of Reclamation and Solano County Water Agency now must operate water deliveries with the specific objective of maintaining sufficient storage in Lake Berryessa to ensure that Accord flow conditions can be met throughout the year.

Anti-Degradation Analysis: The mass balance results also were assessed with respect to the State antidegradation policy. Determining consistency with the state anti-degradation policy is the responsibility of the RWQCB at the time applications are received that involve the discharge of wastes to waters of the state. Consistency with the policy is based on maintaining water quality to the extent “…any change will be consistent with maximum benefit to the people of the State…,” among other findings (Regional Water Quality Control Board 1998). Maximum benefit is based on water quality, social, technological, economic, and legal issues. The SWRCB adopted guidance to Regional Boards for implementation of antidegradation policies in NPDES permitting in 1990 (SWRCB Administrative Procedures Update No. 90-04). The guidance states that a RWQCB may determine it is not necessary to do a “complete” anti-degradation analysis where a discharge satisfies one of the following requirements:

< Reduction of water quality will be spatially localized or limited with respect to the water body, i.e. confined to the mixing zone.

< Reduction in water quality is temporally limited and will not result in long term deleterious effects.

< Action will produce minor effects which will not result in a significant reduction of water quality, e.g., a wastewater treatment plant has a minor increase in the volume of discharge.

< The proposed activity, which may potentially reduce water quality, has been approved in the applicable jurisdiction’s General Plan and has been adequately subjected to the environmental and economic analyses in an EIR required under CEQA. If the EIR is inadequate, the Regional Board must supplement this information to support the decision.

The guidance states that the above considerations may vary by pollutant, e.g., carcinogens, mutagens, and teratogens should receive stricter scrutiny. A primary focus of the analysis is to include the determination of whether, and the degree to which, water quality is lowered. This determination greatly influences the level of analysis required and the level of scrutiny applied to the “balancing” test – i.e., whether the facility is necessary to accommodate important economic or social development, and whether a water quality change is consistent with maximum benefit to the people of the State.


Pursuant to the SWRCB guidance described above, and understanding that the analyses included in this EIR relate only to significant effects on the environment, the project-related changes estimated with the mass-balance analysis using representative 2002 conditions were evaluated qualitatively to identify if the proposed project would substantially lower water quality conditions and may, therefore, be inconsistent with antidegradation policies. The analysis was focused on the magnitude, geographic scope, and frequency of projected changes in receiving water quality. The ultimate determination of conformity with antidegradation policy, however, is dependent on the RWQCB’s consideration and analysis of water quality changes and socio-economic factors mentioned above.

4.1.4.3 PROJECT IMPACTS AND MITIGATION MEASURES

In accordance with the water quality analysis description provided above, each priority parameter was examined to determine if the WWTP effluent concentration under the proposed project would exceed current waste discharge requirements and NPDES permit limits and if Putah Creek water quality would be adversely affected downstream of the WWTP discharge.

Impact 4.1-1. Aluminum. Discharges of WWTP effluent under the proposed project would contain aluminum. However, concentrations of aluminum in the undiluted WWTP effluent would not be high enough to exceed permit limits, and concentrations in receiving water would generally decrease compared to existing conditions and not exceed applicable regulatory guidance criteria. This impact is considered less than significant.

Aluminum is an abundant element in the earth’s outer crust of clay minerals and igneous rock and is normally present in water at low concentrations as inorganic soluble hydroxide complexes, or insoluble precipitates, and adsorbed to clay minerals. However, it can be present in relatively high concentrations in some groundwaters, during high streamflow conditions with elevated sediment concentrations in the water column, in acid mine drainage, or under low pH conditions if the water is in contact with aluminum-bearing minerals. Beyond its common use as a solid metal, it is also present in materials such as baking powder, antacids, cosmetics, dietary supplements, and buffered aspirin. U.S. EPA has established a national recommended water quality criterion for aluminum for potential toxicity to sensitive aquatic organisms, and there is an applicable primary drinking water MCL.

Permit Compliance

The reported mean effluent concentration for aluminum in the WWTP effluent based on 2002 data generally has been lower than the U.S. EPA-recommended water quality criterion (also the NPDES permit limit) of 87 µg/L (Table 4.1-5). However, the maximum effluent concentration of 251 µg/L (Table 4.1-4) indicates that WWTP effluent may have the potential to violate the current NPDES permit limit.

The campus is required by law to report any permit effluent violations to the RWQCB. Accordingly, from 2000 to 2004 the campus has reported a single violation of the 87 µg/L as a 4-day average for aluminum. According to the WWTP self-monitoring reports, the campus


reported a 4-day average of 141 µg/L, which violates the permit level of 87 µg/L. The report identified the cause of the exceedance as being the addition of alum to the wastewater stream to lower effluent turbidity during a moderate storm. Alum is a coagulant that can be added to the wastewater to aid the filtration process for suspended solids removal. Since the time of the violation, the campus has altered its operations and uses organic-based polymers as coagulant aids and no longer adds alum during storm events to lower turbidity levels. Because of the change in operation, the campus does not anticipate having any future exceedances of the permit limit.

The proposed expansion of the WWTP would not change the effluent quality for aluminum. The level of treatment provided by the expansion would remain consistent with the current level of treatment (which reflects reduced levels of aluminum because of the switch from alum to polymers as a chemical filter aid). The future concentration levels for aluminum in the effluent should remain the same as those recently produced. Consequently, the expansion of the facility is not projected to exceed current NPDES permit limits.

Impact to Receiving Water

As indicated in Table 4.1-8, Putah Creek upstream of the WWTP may contain background levels of aluminum that exceed the U.S. EPA recommended criteria of 87 µg/L based on the 2002 dataset for the R1 monitoring station (i.e., Putah Creek upstream of the WWTP discharge). However, the levels of aluminum measured upstream and downstream of the WWTP discharge do not reflect the qualifications that the U.S. EPA has made with regards to the criterion. As explained in a recent communication between the U.S. EPA Office of Water and the Central Valley RWQCB (U.S. EPA 2003a), the criterion of 87 µg/L is based on low total hardness (10-12 mg/L as CaCO3) and low pH (6.5-6.6). At moderate pH and hardness conditions, the U.S. EPA considers 750 µg/L to be a more appropriate criterion for aluminum. However, Putah Creek water quality conditions are not comparable to the conditions that the criteria were based upon. As shown in Table 4.1-7, the observed pH in Putah Creek ranges from a minimum of 7.8 to a maximum of 8.7. Hardness in Putah Creek is also much higher than that used for establishing the recommended criteria. According to the summary of 2002 data, hardness ranges from 148 to 609 mg/L as CaCO3, which is well over ten times higher than the hardness levels used to develop the recommended criteria (i.e., where aluminum toxicity to sensitive organisms would be anticipated). Therefore, the 87 µg/L criterion is overly protective of water bodies such as Putah Creek.

U.S. EPA has provided clarification to the RWQCB that the recommended criteria for aluminum are not meant to apply to aluminum silicate particles. Aluminum silicate (i.e., aluminum bound to clay particles) is nontoxic and is found in natural waters throughout the world. The toxic forms of aluminum are known to be either dissolved forms or particulate forms of aluminum hydroxide. The monitoring data for both WWTP effluent and Putah Creek upstream of the WWTP discharge have been measured as total recoverable aluminum; therefore, neither the dissolved fraction nor the composition of aluminum on particulates can be ascertained from the available data. Because the measured exceedances of the 87 µg/L


criterion at the WWTP are known to be associated with alum additions, and the fact that values have typically been lower than the criterion, the total aluminum measurements create further assurance that aluminum toxicity would be unlikely in effluent or receiving water. This factor adds to the above mentioned issues of high hardness and normal pH that exist in Putah Creek that are not conditions conducive to aluminum toxicity.

Using the mass balance calculation with the 2002 dataset, an expansion of the WWTP would reduce mean concentrations of total aluminum in Putah Creek downstream of the WWTP discharge (Table 4.1-9). Because the future effluent concentration is projected to remain at or below the existing effluent limit of 87 µg/L, the additional discharge volume of WWTP effluent to Putah Creek would help to dilute the current levels of aluminum in the receiving water. Exhibit 4.1-2 shows the reduction in aluminum concentrations in Putah Creek calculated with the mass balance calculation at the current effluent discharge rate of 1.7 mgd, current permitted capacity of 2.7 mgd, and proposed project capacity of 3.8 mgd. As described in the impact assessment methods above, under worst case drought conditions of no streamflow in Putah Creek and effluent values represented by the 2002 dataset, the analysis of receiving water quality effects is the equivalent of the analysis of permit compliance with undiluted effluent. Under the no flow scenario, WWTP effluent would meet the regulatory criteria as described above. Because the proposed increase of WWTP effluent would not further degrade the receiving water and would generally result in lower aluminum concentrations than Putah Creek, the expansion does not violate the state and federal anti-degradation policies.

Based on the discussion provided above, the effluent aluminum concentrations expected to occur under the proposed project are anticipated to comply with effluent permit requirements. Receiving water quality would likely improve as a result of generally lower aluminum concentrations in the WWTP effluent than background Putah Creek levels. Therefore, this impact is considered less than significant.

▪ Mitigation Measures: No mitigation is needed.

Impact 4.1-2. Ammonia. Discharges of WWTP effluent under the proposed project would contain ammonia. However, concentrations of ammonia in the undiluted WWTP effluent would not be high enough to exceed permit limits, and concentrations in receiving water would not exceed applicable regulatory guidance criteria. This impact is considered less than significant.

Ammonia is a key inorganic form of nitrogen in the nitrogen cycle that can be discharged directly or in runoff from sources such as fertilizers and animal fecal wastes, or in organic matter that is converted to ammonia through decay. Ammonia can also be volatile and thus contribute to atmospheric sources and deposition. In aquatic environments, ammonia can be oxidized to nitrite and nitrate nitrogen or be a direct constituent of concern as follows: (1) plant nutrient that stimulates algae and aquatic weed growth; (2) temperature- and pH-dependent toxin to aquatic organisms; and, (3) oxygen demanding substance when converted to nitrate by nitrifying bacteria (U.S. EPA 1986a). The U.S. EPA-recommended water quality criteria provide the relevant guidance values for aquatic life protection.


Table 4.1-9 Mass Balance Analysis Results for Capacity Increase from 2.7 mgd to 3.8 mgd

Pollutants of Concern Units Water Quality Standards or

Criterion 1 Downstream Mean @

3.8mgd Downstream Max @

3.8mgd

Aluminum µg/L 87 a 134 h 440

Ammonia mg/L-N 0.57 b 0.12 0.27

Arsenic µg/L 10 c 2.46 4.11

Copper µg/L 10.4 d 3.2 5.9

Cyanide µg/L 5.2 e 0.69 8.4

Dichloromethane µg/L 4.7e 28.1 h 28.1 h

EC µmhos/cm 900 c 644 776

Dioxin pg/L 0.013 e 44.8 h 44.8 h

Iron µg/L 300 c, f, g 228 831 h, i

Lead µg/L 3.0 d 0.27 1.78

Mercury µg/L 0.05 e 0.01 0.03

Nitrate + Nitrite mg/L-N 10 c 8.5 56 j

pH Standard Unit 6.5–8.5 f 8.1 8.5

Phosphorus, Total mg/L-P NA 0.65 1.4

Turbidity NTU Narrative f 16 66

Source: Larry Walker Associates based on UC Davis WWTP discharge monitoring data. 1. Hardness- and pH-adjustable criteria shown for 2002 dataset conditions where streamflow is present. a. 2002 USEPA Ambient Criteria b. EPA Ambient Water Quality Report, minimum calculated criterion shown based on maximum Putah Creek pH of 8.7 c. State and Federal drinking water MCLs d. CTR minimum criterion based on statistically calculated low hardness of 119 mg/L (99th percentile) e. CTR human health criteria f. Basin Plan g. Applicable Water Quality Standard is in dissolved form h Values exceed applicable objective as result of elevated background Putah Creek concentration; effluent actually reduces the concentration in Putah Creek. i. Samples analyzed as total recoverable concentration. j. Single outlier nitrate+nitrite value of 104 mg/L skews results. NA = Not Available



Aluminum (ug/L) at Downstream Putah Creek

0

50

100

150

200

250

300

350

400

450

500

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

2002

1.7 MGD2.7 MGD3.8 MGD

Aluminum in Putah Creek at 1.7 mgd, 2.7 mgd, and 3.8 mgd Effluent Discharge 4.1-2 EXHIBIT


Permit Compliance

The WWTP processes are operated to nitrify and denitrify wastewater, which reduces both ammonia and nitrate concentrations in the treated wastewater. The maximum recorded ammonia concentration in the WWTP effluent is 1.56 mg/L (Table 4.1-4), which meets the current permit limit of 1.96 mg/L. There have been no reported permit violations for ammonia.

Impact on Receiving Water

The U.S. EPA recommended ambient criteria for ammonia is 0.57 mg/L (based on a maximum observed pH of 8.7). The maximum ammonia concentration measured in Putah Creek upstream of the WWTP discharge was 0.2 mg/L. Based on results of the mass balance calculation with the 2002 dataset shown in Table 4.1-9, the proposed increased discharge of WWTP effluent to 3.8 mgd could incrementally increase ammonia concentrations in Putah Creek. The maximum ammonia concentrations in the receiving water could increase to 0.27 mg/L, which would maintain compliance with the worst-case receiving water quality objective of 0.57 mg/L. The comparison, and minor project-related changes in projected ammonia concentrations in Putah Creek at the existing flow of 1.7 mgd, existing treatment capacity of 2.7 mgd, and proposed 3.8 mgd treatment capacity are shown in Exhibit 4.1-3.

Under drought conditions in Putah Creek, the evaluation of instream ammonia concentrations depends on several factors. When background streamflow is completely absent under extreme drought, the streamflow would consist entirely of effluent and the permit compliance analysis above indicates that the discharge of undiluted effluent would meet the applicable criteria. Under drought conditions with some background minimal streamflow in Putah Creek, the proposed project discharge rate of 3.8 mgd would incrementally increase the amount of wastewater mixed into the streamflow and thus incrementally increase the ammonia concentrations compared to existing 1.7 mgd and current 2.7 mgd design capacity conditions.

As the effluent-to-streamflow ratio increases, the applicable pH-dependent regulatory criteria would also shift in response to the dominance of the effluent pH condition. The effluent pH is generally lower than the variable historical background values in Putah Creek and the applicable criteria (and tolerable ammonia concentrations) increase at lower pH values. Consequently, under drought conditions the applicable criteria would likely be higher, and the representative 2002 effluent dataset analysis described above indicates that ammonia concentrations would be lower than applicable criteria.

Based on the discussion provided above, the effluent and receiving water ammonia concentrations would not cause exceedance of applicable NPDES permit limits or applicable regulatory criteria for receiving water. Therefore, the impact is considered less than significant.




Ammonia (mg/L) at Downstream Putah Creek

0

0.05

0.1

0.15

0.2

0.25

0.3


2002

1.7 MGD

2.7 MGD

3.8 MGD

Ammonia in Putah Creek at 1.7 mgd, 2.7 mgd, and 3.8 mgd Effluent Discharge 4.1-3 EXHIBIT


Impact 4.1-3. Arsenic. Discharges of WWTP effluent under the proposed project could contain arsenic. However, concentrations of arsenic in the undiluted WWTP effluent would not be high enough to exceed permit limits or other applicable water quality criteria, and concentrations in receiving water would not exceed applicable regulatory guidance criteria. This impact is considered less than significant.

Arsenic is a metal used primarily in wood preservation and agricultural chemicals and other arsenic-containing compounds include glass, pesticides, pigments, textile printing, taxidermy, and some lubricating oils. In water, arsenic can be present naturally in inorganic forms with a range of concentrations depending on the natural presence in the watershed or groundwater supplies; organic forms can be produced through bacterial action and can be highly toxic and bioaccumulate in organism tissue, particularly if present in methylated organic forms (i.e., complex of carbon atoms and arsenic) (U.S. EPA 2003b). The lowest applicable regulatory criterion is the primary drinking water MCL; the CTR aquatic life protection criteria are considerably higher. Thus, the MCL is used in this analysis to determine potential significance.

Permit Compliance

The current NPDES permit does not have an effluent limit for arsenic because effluent concentration levels are well below the drinking water MCL (10 µg/L). Therefore, the WWTP discharge was not considered to have a reasonable potential to violate water quality standards by the RWQCB in preparation of the NPDES permit.

Since adoption of its permit in 2003, the highest detectable level of arsenic measured in the WWTP effluent is 7.68 µg/L (Table 4.1-4). Because the level of treatment would remain the same with the expansion, the project is not expected to change the concentration levels of arsenic in effluent. Therefore, there would continue to be no reasonable potential to violate numeric or narrative standards.


Using the mass balance calculation, downstream impacts of the proposed project are not predicted to cause the receiving water to exceed the drinking water MCL. However, the expansion would increase the level of arsenic from a maximum of 3.8 µg/L at the current permitted capacity of 2.7 mgd to a maximum of 4.1 µg/L at 3.8 mgd (see Table 4.1-9). While there is an increase in the maximum concentrations, the maximum concentrations of arsenic are not indicative of violations of the drinking water MCL. It should also be noted that drinking water MCLs were established to protect human health over longer averaging periods (e.g., monthly or longer). Maximums in concentration therefore do not indicate if there is a risk to human health. As a result, the mean concentration is a more appropriate measurement to determine the potential impact on human health. In this case, the calculated values and incremental increases in mean arsenic concentrations in Putah Creek for the 1.7 mgd existing condition to 2.7 mgd existing treatment capacity, and ultimately to the 3.8 mgd proposed capacity, are negligible relative to the applicable criteria and natural background variation as indicated in Exhibit 4.1-4. Based on the collective monthly measured values from 2002, the



Arsenic (ug/L) at Downstream Putah Creek

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5


2002


Arsenic in Putah Creek at 1.7 mgd, 2.7 mgd, and 3.8 mgd Effluent Discharge 4.1-4 EXHIBIT


project-related increase in design capacity from 2.7 mgd to 3.8 mgd would cause a minor increase in the mean annual arsenic concentration in the receiving water from 2.3 to 2.46 µg/L (Table 4.1-9). Under drought conditions of reduced or no background streamflow, the 2002 effluent dataset analysis described above reflects the likely water quality conditions for arsenic which indicate concentrations would be lower than applicable criteria. The projected maximum (refer to Exhibit 4.1-4) and mean arsenic concentrations in Putah Creek associated with the proposed project would not violate the state and federal antidegradation policies.

Based on the discussion provided above, the effluent and receiving water arsenic concentrations would not exceed applicable NPDES permit limits or applicable regulatory criteria for receiving water. Therefore, the impact is considered less than significant.


Impact 4.1-4. Copper. Discharges of WWTP effluent under the proposed project could contain copper. Concentrations of copper in the undiluted WWTP effluent could exceed permit limits, and concentrations in receiving water could exceed applicable regulatory guidance criteria. This impact is considered potentially significant.

Copper is an essential element in plant and animal metabolism in trace quantities; however, it can become toxic to aquatic life at elevated concentrations. Copper is an abundant trace element in the earth’s crust and can be present of background levels or enter water from sources such as pesticides, acid mine drainage, corrosion of copper pipes, copper sulfate (i.e., common aquatic algicide), urban stormwater runoff (e.g., automobile break pad wear), and fabricated metal-leather-electrical products. It can be present in a variety of inorganic forms, depending on pH and oxidation state (e.g., hydroxides, sulfur-/phosphate-/carbonate-bearing complexes, precipitates, and ionic bonds with particulate matter), and in organic complex forms that are much less toxic than the ionic forms (U.S. EPA 2003c). The lowest applicable regulatory criteria used for evaluating potential impact significance are the CTR aquatic life protection criteria; CTR human health criteria and the primary drinking water MCL are much higher.

Permit Compliance

The NPDES permit limits for copper vary depending on the level of hardness in the effluent at the time the sample is taken. Since March 2000, the WWTP has had seven permit violations related to copper. To address the copper violations, the campus conducted an extensive source investigation and implemented new operational procedures to address the permit compliance issues. The new operational procedures include daily monitoring of the influent (raw wastewater entering the treatment plant) for copper to determine if there are any large copper loads entering the facility. If large loads are identified, polymers are injected at the WWTP to control the copper. The injection of polymers enhances the removal of copper through the treatment process.

Table 4.1-10 shows the measured January through July 2004 effluent total copper concentrations and calculated total copper criteria based on measured hardness and the CTR


calculation protocol. Through its daily monitoring, source control efforts, and injection of polymers, the most recent 7 months of monitoring data indicate that copper concentrations in the WWTP effluent have generally been controlled in the applicable CTR criteria. However, recent exceedances occurred in December 2003, January 2004, and July 2004. The exceedance in July was inexplicable and was not detected in the source monitoring and may have been an analytical artifact associated with a different type of sample bottle than had been used. The campus aggressively investigated the December 2003 and January 2004 exceedances and believes they probably originated at a campus research facility where discharges of copper sulfate solution used for disinfection of animal feet were occurring in areas subject to stormwater runoff into the sewer system. UC Davis staff have since been directed to discontinue this practice and eliminate these discharges. Regardless, the potential apparently still exists for effluent concentrations to exceed NPDES permit limits despite the aggressive daily plant performance monitoring and campus source control efforts. Because compliance with effluent limits is a threshold for significance of impacts, the recent violations of effluent limits lead to a finding that the impact of copper discharges is potentially significant. If effluent limits are revised in the future to address site-specific toxicity (refer to Section 4.2-4, Impact 4.2-4, for a more detailed analysis of copper effects on aquatic resources and allowable revision of effluent limits based on site-specific adjustment of the water effects ratio used in the CTR criteria compliance calculation), this finding of significance may be revised.


Projected copper concentrations in Putah Creek downstream from the WWTP were compared to the applicable CTR criteria. To determine the copper standard for a given water, the level of hardness in the receiving water must be considered. Using the 2000-2004 dataset, the 99th percentile level of hardness in the receiving water is 119 mg/L as CaCO3 (Table 4.1-4). At a hardness concentration of 119 mg/L, the chronic water quality standard for copper is 10.4 µg/L as a 4-day average.

Table 4.1-10 Comparison of Recent WWTP Effluent Copper Concentrations to Calculated Criteria

Month Effluent Total Copper

(mean/maximum) (µg/L) Hardness (mg/L CaCO3) Calculated CTR Criteria a (µg/L)

January 13.4 / 20.1 200 16 February <5 / <5 180 15

March 4.8 / 4.8 214 17 April 7.5 / 7.5 170 14 May <5 / <5 170 <14 June <5 / <5 160 <13 July 5.5 / 24.5 188 15

Notes: Source: Larry Walker Associates based on UC Davis discharge monitoring data from 2004. a Applicable total copper criteria based on the measured hardness value using the CTR equation.


The mass balance calculations for the project expansion indicate that WWTP discharge would not cause the Putah Creek downstream of the WWTP discharge to exceed the CTR criteria (Table 4.1-9). However, the increased flow would cause a slight incremental increase in the mean concentration of copper in Putah Creek as indicated in the plot of conditions under the 1.7 mgd existing condition, 2.7 mgd existing treatment capacity, and to the 3.8 mgd proposed capacity (Exhibit 4.1-5). The incremental increase in the mean annual copper concentration in Putah Creek from 2.9 µg/L to 3.2 µg/L, associated with increased WWTP capacity from 2.7 mgd to 3.8 mgd, is small relative to the applicable criterion of 10.4 µg/L and would not violate the state or federal antidegradation policies. Under drought conditions of reduced or no background streamflow, the 2002 effluent dataset analysis described above reflects the likely water quality conditions for copper and indicates concentrations would be lower than applicable criteria.

Based on the discussion provided above, the effluent copper concentrations have exceeded applicable NPDES permit limits and there is the potential for receiving water concentrations to exceed applicable regulatory criteria. Therefore, the impact is considered potentially significant.

▪ Mitigation Measure 4.1-4: Implement a phased evaluation/source control measure to address effluent copper levels.

UC Davis will continue to monitor effluent copper concentrations and evaluate whether the frequency and measured concentration (i.e., assuming it continues to be detected in the future) warrant further measures to control its discharge to Putah Creek. Should future monitoring indicate a continued reasonable potential to exceed regulatory thresholds, the likely feasible operational change would be to modify the frequency of influent and effluent monitoring to implement earlier detection and treatment process modifications.

Because the daily monitoring and subsequent polymer additions when copper loading is detected has generally been successful, and the fact that the latest exceedance appears not to be associated with influent loading, continued operation with this protocol is considered to be an effective means of controlling copper exceedances. Implementation of this mitigation would reduce the impact to a less-than-significant level.

Impact 4.1-5. Cyanide. Discharges of WWTP effluent under the proposed project could contain cyanide. While observed concentrations of cyanide in the undiluted WWTP effluent have not exceeded the permit limits, there is uncertainty whether the effluent and receiving water will reliably achieve applicable regulatory criteria. This impact is considered to be potentially significant.

Cyanide is a toxic compound. Sources of cyanide are sodium and potassium cyanide salts including ore extraction processes, electroplating, printing, fumigation, photography, and various other manufacturing processes. The chemical speciation of cyanides varies according to their source. The most common forms of cyanide in the environment are metallocyanide complexes, free cyanides, and synthetic nitriles. Cyanide is commonly formed as a disinfection



Copper (ug/L) at Downstream Putah Creek

0

1

2

3

4

5

6

7


2002


Copper in Putah Creek at 1.7 mgd, 2.7 mgd, and 3.8 mgd Effluent Discharge 4.1-5 EXHIBIT


byproduct in wastewater treatment. Mechanisms and controlling factors for cyanide formation are complicated and poorly understood. Free cyanide is the primary toxic agent to aquatic organisms (Eisler 1986) and is the form used in the derivation of U.S. EPA criteria for aquatic life protection and associated CTR criteria. The CTR criteria are the lowest applicable regulatory criteria used for evaluating potential impact significance; the primary drinking water MCL is much higher.

Permit Compliance

The current NPDES permit contains two effluent limitations for cyanide, 5.2 µg/L as a 4-day average and 22 µg/L as a maximum concentration. The highest detected level for cyanide in the WWTP effluent was 21 µg/L (Table 4.1-4), which is below the permitted maximum concentration for a single sample. The mean effluent concentration is 3 µg/L, which is below the permit limit. Because the mean and maximum detected levels of cyanide are below the applicable permit limits and the concentration level of cyanide is not anticipated to change with the project, the WWTP discharge is anticipated to continue to comply with the NPDES permit limits. However, given the magnitude of the highest detected effluent value, there is uncertainty whether the plant can reliably achieve the 4-day average limit of 5.2 µg/L. Therefore, the impact of the proposed project is considered potentially significant.


The 2002 dataset represents the only cyanide data measured by the WWTP upstream of the campus discharge (Table 4.1-8). The analytical detection limit used to obtain these data was 5 µg/L. In 11 of 12 measurements, the result was no detection. Such results indicate compliance with the cyanide water quality standard of 5.2 µg/L as established in the CTR, and the single result of 6.7 µg/L does not appear to be representative of routine conditions in the creek. In general, receiving waters in the Central Valley do not contain detectable levels of cyanide (i.e., <5 µg/L).

Given that only single effluent and receiving water samples collected on the same day in the entire year-long special monitoring conducted by the WWTP in 2002 had detectable levels of cyanide, conclusions regarding the potential magnitude or frequency of occurrence are speculative. Projected levels of cyanide in the creek downstream of the campus discharge based on the mass-balance analysis (Table 4.1-9 and Exhibit 4.1-6) indicate that the incremental increases between 1.7 mgd, 2.7 mgd, and 3.8 mgd effluent discharge rates may be relatively minor. Given the large majority of undetected values, the data indicate that the proposed project would not likely violate water quality standards for cyanide and would not have a significant adverse impact on the receiving water. Under no-flow drought conditions, the effluent dataset analysis above indicates that cyanide concentrations would be lower than applicable criteria.



Cyanide (ug/L) at Downstream Putah Creek

0

1

2

3

4

5

6

7

8

9


2002


Cyanide in Putah Creek at 1.7 mgd, 2.7 mgd, and 3.8 mgd Effluent Discharge 4.1-6 EXHIBIT


Based on the above discussion, the effluent and receiving water cyanide concentrations would likely be in compliance with applicable NPDES permit limits or applicable regulatory criteria for receiving water. However, intermittent violations could occur based on past performance. Therefore, the impact is considered potentially significant.

▪ Mitigation Measure 4.1-5: Implement a phased evaluation/source control measure to address effluent cyanide levels.

(a) Part A: When conducting monitoring per the NPDES permit requirements, UC Davis will collect four consecutive days of effluent composite samples, rather than one grab sample, so that a true 4-day average cyanide concentration can be determined. Also UC Davis will collect grab samples on each day at the R1 (upstream) monitoring station and analyze for cyanide. Finally, the R1 and effluent flows will be recorded for the same days. If this monitoring demonstrates that the chronic (4-day average) cyanide CTR objective is not exceeded in Putah Creek downstream of the WWTP more often than once in 3 years, no further efforts need be expended. Conversely, if this monitoring indicates that the CTR chronic cyanide criterion is or has reasonable potential to be exceeded in the receiving water more often than once in 3 years, Part B of this mitigation shall be implemented.

(b) Part B involves conducting an evaluation to determine the source(s) of the cyanide, and developing and implementing modifications to WWTP operations and facilities to consistently comply with the CTR cyanide criterion in the receiving water, where it applies. Measures may be required that could include adjusting the WWTP’s industrial pretreatment program and inspection of campus-wide facilities to reduce discharges.

If violations do occur it is assumed that UC Davis will be successful at determining and controlling the source. Therefore, implementation of this mitigation would reduce the impact to a less-than-significant level.

Impact 4.1-6. Dichloromethane. Discharges of WWTP effluent under the proposed project could contain dichloromethane. However, concentrations of dichloromethane in the undiluted WWTP effluent would not be high enough to exceed permit limits, and concentrations in receiving water would not exceed applicable regulatory guidance criteria. This impact is considered less than significant.

Dichloromethane (known as methylene chloride) is a liquid organic compound used in paint removers, fumigants for strawberries and grains, foams, adhesives, and furniture. The compound dissolves in water but is volatile when exposed to air; it is not readily adsorbed by aquatic sediment and therefore can enter the groundwater (U.S. EPA 1994). At elevated levels, the compound is a neurotoxin and probable human carcinogen primarily associated with exposure by inhalation, and is only slightly toxic to aquatic organisms exposed to dissolved concentrations. The CTR criteria for human health are the lowest applicable regulatory criteria used for evaluating potential impact significance; the primary drinking water MCL is slightly higher.


Permit Compliance

The campus has a permit limit of 4.7 µg/L for dichloromethane as a monthly average. Of a total of 31 effluent samples that have been analyzed for dichloromethane because the WWTP became operational, there have been only 3 detections and the mean and maximum concentrations and these have not exceeded the permit limit (Table 4.1-4). Compliance with the existing effluent limit is anticipated to continue under the proposed project.


The CTR applicable receiving water quality standard for dichloromethane is also 4.7 µg/L. The current dichloromethane permit limit for the WWTP was established because the compound was detected in Putah Creek upstream from the WWTP discharge above the CTR criteria once in February 2002 with a value of 35 µg/L. Putah Creek data for dichloromethane taken upstream of the WWTP discharge have not exceeded the criteria since the time of the single exceedance in 2002 described above. The single background value is also the source of the apparent exceedance in the mass balance analysis (Table 4.1-9). Based on the available effluent and Putah Creek data for dichloromethane, and the expected similar effluent quality for the proposed project, the proposed project is not anticipated to cause or contribute to violations of the receiving water standard or otherwise adversely impact uses. Under no-flow drought conditions, the effluent dataset analysis above indicates that dichloromethane concentrations would be lower than applicable criteria.

Based on the discussion provided above, the effluent and receiving water dichloromethane concentrations would not cause exceedance of applicable NPDES permit limits or applicable regulatory criteria for receiving water. Therefore, the impact is considered less than significant.


Impact 4.1-7. Dioxin. Discharges of WWTP effluent under the proposed project could contain dioxin. The existing data indicate that the WWTP would probably continue to comply with NPDES permit limits. While projected effluent concentrations are not expected to change with the proposed project, compliance with receiving water quality objectives cannot be confirmed with certainty because of the limited dataset available. This impact is considered potentially significant.

Dioxin (and other closely related forms of chlorinated dioxin and furan congeners) are contaminant byproducts of manufacturing including production of other chlorinated organic compounds and paper-pulp processing, and may also be formed during combustion of chlorinated organic compounds, automobile exhaust, and municipal solid waste. A congener refers to a single specific spatial arrangement of elements and chemical bonds in the general dioxin molecule; the term dioxin refers to the family of multiple congeners that can exist in the environment. Dioxin is an organic solid that is relatively insoluble in the aquatic environment and strongly adsorbed by soil and sediment, is chemically stable, is resistant to decay, and is bioaccumulative in organism tissues. Aquatic toxicity information is variable depending on many exposure-, environment-, and organism-specific factors, however, toxicity effects are


documented at low exposure levels (U.S. EPA 2004). In humans, dioxin is a probable human carcinogen, and high-levels of exposure have been associated with neurodevelopment, immune system, diabetes, liver damage, and heart disease problems; however, effects of low-level exposure are not definitive and are an issue of ongoing research (National Institutes of Health 2004). The lowest applicable regulatory criteria are the CTR aquatic life protection criteria for a single dioxin congener (2,3,7,8-TCDD).

Permit Compliance

The current effluent limit for dioxins in the WWTP permit is 0.014 picograms per liter (pg/L). In 31 effluent samples, 30 indicated no detectable level of dioxin congeners. One effluent sample collected in July 2002 had a detected value of 12 pg/L. Given the body of evidence on effluent quality, the single detected value does not appear to be representative of typical effluent quality. However, because the detection limit for dioxin is significantly higher than the effluent limit, conclusive statements regarding future compliance with that limit cannot be made.


The current dioxin permit limit was established because one of the congeners was detected in Putah Creek in July 2002 at 55.9 pg/L. However, there are no available receiving water data for the specific 2,3,7,8-TCDD dioxin congener. Therefore, no conclusions can be drawn about the current compliance with the CTR standard.

With the exception of 2,3,7,8-TCDD, five receiving water samples of the WWTP have been tested since 2002 for a full range of dioxin congeners. Detected concentrations of congeners were observed on three occasions. Detection limits for these analyses were orders of magnitude above the effluent limit in the existing permit. The available data do not provide a coherent picture of actual dioxin conditions in the receiving water given the detection limits used in the analysis. As such, an impact analysis cannot be completed for this parameter without additional, verifiable data on both effluent and ambient conditions.

Based on the above discussion, the existing and future compliance of effluent and receiving water dioxin concentrations with regulations is uncertain. Therefore, the impact is potentially significant.

▪ Mitigation Measure 4.1-7. Implement a phased evaluation/source control measure to address effluent dioxin levels.

UC Davis will continue to monitor effluent concentrations of dioxin and evaluate whether the frequency and measured concentration (i.e., assuming they continue to be detected in the future) warrant further measures to control their discharge to Putah Creek. Should future monitoring indicate a reasonable potential for dioxins to exceed regulatory thresholds, the likely feasible operational change would be to include dioxins into the existing industrial pretreatment program for the WWTP.


This measure would require specific evaluations to determine sources of dioxins in the wastewater and develop and implement source control measures. Because sources of dioxin are generally well understood, if violations do occur it is assumed that UC Davis will be successful at determining and controlling the source. Therefore, implementation of this mitigation would reduce the impact to a less-than-significant level.

Impact 4.1-8. Iron. Discharges of WWTP effluent under the proposed project would contain iron. However, concentrations of iron in the undiluted WWTP effluent would not be high enough to exceed permit limits, and concentrations in receiving water would not exceed applicable regulatory guidance criteria. This impact is considered less than significant.

Iron is a primary element in the earth’s crust, in soil, in aquatic sediments, and it is naturally occurring in surface and groundwater supplies. Iron can also be discharged to water from corrosion of iron-based metals, or specific manufacturing processes. The primary ionic forms of iron include the dissolved ferrous form in low-oxygen water and the relatively insoluble ferric form in aerated water associated with sulfur- phosphate- and carbonate-mineral complexes; it can also be found at high concentrations with high organic matter content waters as dissolved organometallic humic and fulvic compounds (U.S. EPA 1986a). In water, iron is an essential element for aquatic plant growth and can be a factor in limiting algae growth. Iron is a concern in municipal drinking water supplies for its ability to cause stains in plumbing and laundry, however, it is not a toxic constituent. The only applicable criterion is the secondary drinking water MCL for aesthetic (e.g., stain formation in laundry and fixtures, undesirable taste and odor) concerns in tap water.

Permit Compliance

The campus has a permit limit for iron of 300 µg/L as a 30-day average. Table 4.1-4 indicates that the highest detected level of iron in a single effluent sample was 445 µg/L, however, that sample was taken before the adoption of the 2003 NPDES permit and was not considered a permit violation. Since the adoption of the permit in 2003, the campus has recorded no permit violations for iron. The mean concentration of iron in the WWTP effluent based on the 2002 dataset was 72 µg/L (Table 4.1-5), and the annual mean was about 30 µg/L in 20003. Because only the single elevated value exceeded the regulatory criteria before establishment of the NPDES permit limit, and because the levels of iron in the effluent have remained very low relative to the criteria, it is anticipated that effluent quality will continue to be in compliance under the proposed project.


The Basin Plan objective for iron is 300 µg/L as dissolved iron. This objective is intended to protect drinking water uses and is consistent with the secondary MCL for dissolved iron of 300 µg/L. Putah Creek upstream of the WWTP discharge had a mean total recoverable iron concentration of 266 µg/L and a maximum concentration of 988 µg/L recorded in 2002 (Table 4.1-7). However, no data are available for dissolved iron, which is often significantly lower than total iron levels in natural waters. A mean receiving water concentration of 228 µg/L


based on total recoverable data for the mass-balance analysis of the proposed project 3.8 mgd discharge rate (Table 4.1-9) indicates that the effluent can be expected to have a diluting effect and help lower the concentration of iron in Putah Creek. Under no-flow drought conditions, the analysis above indicates that iron concentrations would be lower than applicable criteria.

Similar to aluminum described above, an increase in the WWTP discharge from the existing 1.7 mgd flow, to its permitted capacity of 2.7 mgd, and up to the 3.8 mgd proposed capacity would have a diluting effect on iron concentrations in Putah Creek because of the lower mean concentration in WWTP effluent (Exhibit 4.1-7). As a result, the project would not violate the state and federal antidegradation policies.

Based on the above discussion, the effluent and receiving water iron concentrations would not likely cause exceedance of applicable NPDES permit limits or applicable regulatory criteria for receiving water. Rare exceedances of the secondary MCL in the receiving water would not be a significant effect on the environment because the secondary MCL is established to be protective of aesthetic qualities in municipal water supplies rather than for protection of impairment to instream aquatic resources. Therefore, the impact is considered less than significant.


Impact 4.1-9. Lead. Discharges of WWTP effluent under the proposed project could contain lead. However, concentrations of lead in the undiluted WWTP effluent would not be high enough to exceed permit limits, and concentrations in receiving water would not exceed applicable regulatory guidance criteria. This impact is considered less than significant.

Lead is a metal present in trace quantities in soils and rock, and was used historically (but no longer) in manufactured products such as lead-based paints and gasoline. Lead can be introduced into water through sources such as corrosion of old lead-containing plumbing fixtures, batteries, and ammunition, and through urban runoff. The primary risk to humans (especially children) is from inhalation of lead-bearing dust; however, ingestion is also a concern and there is an applicable primary drinking water MCL (U.S. EPA 2004). In the aquatic environment, lead is relatively immobile because of adsorption to sediment. Lead is toxic to aquatic organisms at specific levels but doesn’t bioaccumulate in tissue (U.S. EPA 1986a). The CTR chronic (i.e., 4-day average) criterion for aquatic life is the lowest applicable objective; the primary drinking water MCL is slightly higher and the CTR acute criterion for aquatic life is considerably higher.

Permit Compliance

The NPDES hardness-adjusted effluent limit for lead is 3.6 µg/L at the minimum recorded hardness of 110 mg/L. The WWTP effluent data (Table 4.1-4) indicate that lead concentrations are generally in compliance with the NPDES permit effluent limit, with a mean



Iron (ug/L) at Downstream Putah Creek

0

100

200

300

400

500

600

700

800

900

1000


2002


Iron in Putah Creek at 1.7 mgd, 2.7 mgd, and 3.8 mgd Effluent Discharge 4.1-7 EXHIBIT


concentration of 0.7 µg/L from 19 samples (Table 4.1-4). A single elevated effluent sample with lead content of 7.4 µg/L measured in June 2002 appears not to be representative of the routine performance of the campus WWTP, given that other observed effluent concentrations were less than 0.5 µg/L. The sporadic nature and extreme magnitude of the observed maximum value in comparison to all other UC Davis samples and other wastewater treatment facilities supports the interpretation that the proposed project would likely comply with established effluent limits.


The hardness-adjusted CTR water quality standard for lead is 3.0 µg/L, based on a 99th percentile hardness value of 119 mg/L. Results of the mass balance analysis indicate that the projected mean and maximum downstream receiving water quality lead concentration using 2002 data would be less than the minimum-hardness-based CTR standard (Table 4.1-8). Additionally, the projected incremental change in downstream water quality between the 1.7 mgd existing flow, the 2.7 mgd permitted capacity, and the 3.7 mgd flows of the proposed project would be minor (Exhibit 4.1-8) and well below the applicable CTR standard. Therefore, the proposed project would not have significant adverse impacts on the receiving water and would not result in permit exceedances. Under no-flow drought conditions, the analysis above indicates that lead concentrations would be lower than applicable criteria.

Based on the above discussion, the effluent and receiving water lead concentrations would not likely exceed applicable NPDES permit limits or applicable regulatory criteria for receiving water. Therefore, the impact is considered less than significant.


Impact 4.1-10. Mercury. Discharges of WWTP effluent under the proposed project could contain mercury. However, concentrations of mercury in the undiluted WWTP effluent would not be high enough to exceed any permit limits, and concentrations in receiving water would not exceed applicable regulatory guidance criteria. This impact is considered less than significant.

Elemental mercury is a liquid metal at room temperature. Mercury is found in natural deposits or as cinnabar ores. Substantial contamination occurred in the Central Valley in association with the historical use of mercury in gold mining and refining operations, including in the upper Putah Creek watershed. Lower Putah Creek is identified by SWRCB on the EPA 303(d) list of water quality limited segments for mercury (SWRCB 2003). Other mercury sources may include manufactured products (e.g., batteries, fluorescent light bulbs, electrical switches, thermometers), and a variety of processes (e.g., combustion of fossil fuels, incineration of wastes, cement production, metal refining) (U.S. EPA 2004). In the aquatic environment, mercury is a toxic and bioaccumulative substance in both inorganic and methylated organic forms. Methyl mercury is the most hazardous form of mercury because of its chemical stability, ionic properties that allow it to penetrate cell membranes, and tendency to accumulate in tissues of aquatic organisms (Eisler 1987). Bioaccumulation in a number of rivers and other water bodies have resulted in public health advisory notices issued for selected fish species



Lead (ug/L) at Downstream Putah Creek

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2


2002


Lead in Putah Creek at 1.7 mgd, 2.7 mgd, and 3.8 mgd Effluent Discharge 4.1-8 EXHIBIT


in the Delta and in San Francisco Bay to alert the public to potential health hazards of consuming contaminated organisms. The CTR has the lowest relevant criteria based on human health protection for total recoverable mercury; the primary drinking water MCL is several times higher.

Permit Compliance

The existing NPDES permit does not contain effluent limits for mercury. However, Putah Creek in the project area is listed on the state’s 2002 303(d) list because of elevated levels of mercury in some species of fish. The 303(d) listing carries a requirement to formulate a TMDL to address the human health and wildlife concerns related to mercury levels in fish tissue. The TMDL will include a waste load allocation process for point source dischargers in the Putah Creek watershed, which will include UC Davis, and will result in the regulation of total mass discharges of mercury in the watershed. It is anticipated that the RWQCB would require the NPDES permit to be modified in the future to be consistent with the wasteload allocation. Until the TMDL and waste load allocation are completed, WWTP effluent discharges cannot be assessed for compliance with a TMDL. Mean and maximum levels of mercury in the undiluted effluent are 0.004 and 0.02 µg/L, respectively, which are substantially less than the existing CTR water quality standard for mercury of 0.050 µg/L.


Levels of total mercury in Putah Creek water samples range from less than 0.001 µg/L to a maximum of 0.03 µg/L. These levels are in compliance with the existing CTR standard of 0.050 µg/L. Assessment of the impact of the proposed project on these effluent levels (see Exhibit 4.1-9) indicates no appreciable incremental change in mercury levels in the creek. The mass-balance analysis results (Table 4.1-8) and plot of projected mercury concentrations at the existing 1.7 mgd, current 2.7 mgd capacity, and proposed 3.8 mgd discharge rates indicate that the WWTP effluent generally would be expected to provide a diluting effect to the higher background levels in Putah Creek. Mercury loadings from the proposed project are not anticipated to exceed the CTR standard and would not have a significant impact on beneficial uses in Putah Creek or downstream waters. Under no-flow drought conditions, the analysis above indicates that mercury concentrations would be lower than applicable criteria.

Based on the above discussion, the effluent and receiving water mercury concentrations would not exceed applicable NPDES permit limits or applicable regulatory criteria for receiving water. Therefore, the impact is considered less than significant.


Impact 4.1-11. Nitrate and Nitrite. Discharges of WWTP effluent under the proposed project would contain nitrate + nitrite. However, concentrations of nitrate + nitrite in the undiluted WWTP effluent would not be high enough to exceed permit limits, and concentrations in receiving water would not exceed applicable regulatory guidance criteria. This impact is considered less than significant.



Mercury (ug/L) at Downstream Putah Creek

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035


2002


4.1-9 EXHIBIT Mercury in Putah Creek at 1.7 mgd, 2.7 mgd, and 3.8 mgd Effluent Discharge


Nitrate and nitrite are two oxidized forms of inorganic nitrogen and key factors in the nitrogen cycle and aquatic environments. Nitrite rapidly oxidizes to nitrate and is generally present in oxygenated waters only at very low levels. The primary source of nitrate is fertilizers, domestic and animal waste discharges, and decay of organic matter. Nitrate does not bind to soil and can easily migrate to the groundwater. In the aquatic environment, nitrate is a key nutrient for aquatic plants and algae and excessive levels can contribute to organic enrichment and biological production in surface waters. Nutrient and organic enrichment is known as eutrophication, and becomes a problem when undesirable conditions occur such as nuisance algal blooms, dense aquatic plant growth, and related secondary effects such as dissolved oxygen depletion, plant decay and odors, and reduced water clarity. These undesirable conditions can affect recreational and aesthetic uses, water supply uses, and aquatic life uses. Nitrate and nitrite levels can be reduced through the process of denitrification – a bacterial process that produces elemental nitrogen gas, which then escapes to the atmosphere. Nitrate and nitrite are a concern to human health if high levels are ingested, particularly for infants or fetuses during pregnancy, where it can interfere with oxygen and hemoglobin functions in the blood causing a condition called methemoglobinemia (U.S. EPA 1986a). The applicable regulatory criteria are the primary drinking water MCLs of 1 mg/L N as nitrite and 10 mg/L N as nitrate.

Permit Compliance

The WWTP is operated to nitrify and denitrify wastewater, which reduces nitrogen concentrations in the wastewater and effluent discharged to Putah Creek. Nitrification occurring in the WWTP process units converts ammonia (commonly present at 20 to 40 mg/L N) to nitrate in the final effluent, with final effluent ammonia levels of about 1 to 2 mg/L N. The denitrification process converts nitrate and nitrite that accumulates from the nitrification process to nitrogen gas, thereby reducing nitrate + nitrite concentrations to about 5 to 10 mg/L N in the final effluent (refer to Table 4.1-4). Although the WWTP effluent test results indicate that concentrations in single daily samples can be higher than 10 mg/L on an infrequent basis, the WWTP has a good record of permit compliance and has not exceeded the permit limit that is based on the 30-day average. The observed maximum concentration of 104 mg/L recorded in October 2002 (Table 4.1-4) is not considered representative of typical WWTP effluent quality. The reported value was analyzed at a commercial lab; however, informal tests conducted by staff at the WWTP two days before and two days after the date of the recorded sample had results of 8.0 mg/L and 5.2 mg/L, respectively (Boele pers. comm.). Additionally, the maximum recorded receiving water value upstream of the WWTP discharge of 23 mg/L (Table 4.1-4) was also extremely elevated relative to the other samples from Putah Creek. Similar high nitrate values were observed during the April 2002 sampling with a value of 42 mg/L in the effluent and 7.8 mg/L in the Putah Creek sample. These values for nitrogen in the form of nitrate are also excessive relative to the the historical record of WWTP effluent sampling results for total inorganic nitrogen from nitrate+nitrite and ammonia, and thus are inconsistent with the record of WWTP performance. Given the extraordinary magnitude of these values, supporting information from the WWTP tests, and lack of explanation for such nitrate levels in effluent in relation to ammonia and other nitrogen forms, the maximum


values are believed to be outliers. The pattern of uncharacteristic high values, analyzed at the same time, and taken from two completely independent water bodies indicate that general sample contamination or analytical error may be a factor. The proposed project would continue the nitrification/denitrification treatment process and would not be expected to change the level of nitrate + nitrite in the effluent from the current condition, and compliance with the permit limit is expected to continue.


The applicable receiving water quality standard for nitrate is 10 mg/L, which is based on the primary drinking water MCL intended to be applied to tap water to protect human health. Background concentrations in Putah Creek upstream of the WWTP discharge have a mean level of nitrate + nitrite of 4.4 mg/L (Table 4.1-6). The mass-balance analysis using representative 2002 data (Table 4.1-8) indicates that the proposed project would increase mean concentrations of nitrate to 8.5 mg/L, a level that would continue to comply with the MCL. The project-related changes of instream nitrate concentrations appear to be incrementally minor between the existing 1.7 mgd condition, the current 2.7 mgd permitted capacity and the proposed 3.8 mgd discharge rates relative to the existing conditions and would be below the 10 mg/L MCL (Exhibit 4.1-10).

Under drought streamflow conditions, the increased discharge rate of 3.8 mgd would incrementally increase instream nitrate concentrations compared to the increases that would occur under existing 1.7 mgd and current 2.7 mgd permit capacity discharge rates. Under the extreme no-flow condition, the streamflow would consist entirely of effluent and there would be no project-related change in potential instream nitrate conditions because the proposed project is not expected to change nitrate levels in the effluent. The incremental increases in nitrate concentrations under drought conditions with some background flow present might affect algae growth, however, the degree to which this could occur is uncertain. Nutrients such as phosphorus and nitrogen and a host of other environmental factors (e.g., temperature, light, velocity, turbulence, turbidity, etc.) all influence the degree to which aquatic plant populations occur in natural waters. Nutrient concentrations are not necessarily or independently predictive of biostimulatory impacts. Therefore, the available nitrate data in Putah Creek do not provide conclusive information regarding the impact of the existing or proposed discharge on beneficial uses. Neither the UC Davis Office of Resource Management and Planning, or the Office of Operations and Maintenance (including WWTP staff) have received any complaints of nuisance algae or aquatic plant growth in Putah Creek downstream from the WWTP discharge, and there are no known other complaints.

Several other factors associated with a drought scenario must be considered. Under the Accord in particular, the instream flow rates are higher in late summer and the frequency of low flows is expected to be less than before the Accord. Consequently, the expected frequency and duration of conditions during which incremental increases in nitrate levels could stimulate additional algae growth is expected to be low. Also, while increased algae growth is an aesthetic concern to humans, some level of algal growth is beneficial to the aquatic ecosystem.



Nitrate (mg/L) at Downstream Putah Creek

0

2

4

6

8

10

12


2002


Nitrate in Putah Creek at 1.7 mgd, 2.7 mgd, and 3.8 mgd Effluent Discharge 4.1-10 EXHIBIT


Based on the above discussion, the effluent and receiving water nitrate + nitrite concentrations would not likely exceed applicable NPDES permit limits or applicable regulatory criteria for receiving water or cause substantial changes in algal growth conditions. Therefore, the impact is considered less than significant.

▪ Mitigation: No mitigation needed

Impact 4.1-12. pH. Discharges of WWTP effluent under the proposed project have the potential to alter pH. However, pH levels in the undiluted WWTP effluent would not be expected to exceed permit limits, and changes in receiving water would not exceed applicable regulatory guidance criteria. This impact is considered less than significant.

The pH value is a measure of the hydrogen ion concentration in water; a pH value of 7 means the water has a neutral pH whereas lower pH values represent conditions with relatively more acidity present and higher pH values means relatively more basic conditions are present. Inorganic carbonate, bicarbonate, hydroxide, and phosphate compounds are important in preventing water from becoming too acidic. The pH value is important for metabolism of aquatic organisms such as passage of materials through cell membranes, and metal compounds tend to be more toxic under extremely low pH conditions (U.S. EPA 1986a). The applicable Basin Plan water quality objective is to maintain pH in a range of 6.5 to 8.5 and to limit changes to less than 0.5 units.

Permit Compliance

The existing NPDES permit specifies that the WWTP effluent shall not have a pH less than 6.5 nor greater than 8.5. Data reflective of current performance indicate that the minimum pH level is greater than 6.5, the mean pH level is 7.9, and the maximum pH level is consistently less than or equal to 8.5. A single effluent sample with pH of 8.7 was measured, however, the low frequency of extreme values indicates that the treatment plant routinely meets the permit limits. Such quality meets the existing effluent limits and supports a finding that the proposed project would comply with the existing effluent limits.

Impact on Receiving Waters

The Basin Plan requires that pH levels in receiving waters not be less than 6.5 or more than 8.5. Observed pH levels in Putah Creek range from 7.6 to 8.9. Given the pH of the WWTP effluent, the mass balance analysis (Table 4.1-8) indicates that the WWTP does not currently, and would not in the future, cause or contribute to violations of the receiving water quality objectives in the future. Therefore, the proposed project would not have a significant adverse impact on pH levels in Putah Creek. Under no-flow drought conditions, the analysis above indicates that pH levels would meet applicable criteria.

Based on the discussion provided above, the effluent and receiving water pH concentrations would not cause exceedance of applicable NPDES permit limits or applicable regulatory criteria for receiving water. Therefore, the impact is less than significant.



Impact 4.1-13. Phosphorus. Discharges of WWTP effluent under the proposed project would contain phosphorus. However, there are currently no applicable regulatory criteria for either the NPDES permit or receiving water. The biostimulatory responses of aquatic plants (i.e., algae or macrophytes) to phosphorus depend on concentrations, and the proposed project would not change existing phosphorus concentrations in WWTP effluent. This impact is considered less than significant.

Phosphorus is a common element of the soil and rock without a gaseous phase; however, it can be a component of atmospheric deposition associated with particulate matter transport by wind. Phosphorus is a primary nutrient for aquatic algae and plants and can be a “limiting” nutrient for plant growth. Phosphorus generally binds strongly to soil, clay, and organic matter; however, it can be released from aquatic sediment when there is no oxygen present (U.S. EPA 1986a). Sources include fertilizers, detergents, wastewater effluent, and organic matter. No applicable regulatory criteria for phosphorus have been established.

Permit Compliance

The NPDES permit does not contain effluent limits for phosphorus. However, Finding 25 of the permit addresses concerns that phosphorus may promote biostimulation of aquatic plants, which could cause nuisance conditions or adversely affect beneficial uses. Nuisance conditions might include aesthetic impairment produced by algal mats or restricted navigation because of dense aquatic plant growths. Water quality problems could include low dissolved oxygen, odors, or excessive pH. The permit requires monitoring of phosphorus in effluent and receiving waters to address this concern. Because the proposed project would expand the existing treatment processes, it is anticipated that implementation of the proposed project would not change existing phosphorus concentrations in WWTP effluent.


There are no water quality objectives or U.S. EPA ambient criteria for phosphorus. As described for nitrate, phosphorus, nitrogen and other environmental factors influence the degree to which aquatic plant populations occur in natural waters. In nutrient rich streams, phosphorus is often not a controlling factor in limiting the extent of algae growth because as little as 0.05 mg/L phosphorus can stimulate algae (U.S. EPA 1986a). This may be the case for the UC Davis discharge, because phosphorus levels are relatively high compared to the low levels that can stimulate algae. Because the concentration of phosphorus in the WWTP effluent is not expected to change with the proposed project, biostimulatory conditions in Putah Creek are likewise not expected to change from existing conditions. Exhibit 4.1-11 indicates incremental increases in levels of phosphorus in downstream receiving waters associated with the proposed project. The plot shows that the increases associated with increasing discharge to the current 2.7 mgd permit capacity and up to 3.8 mgd from the existing 1.7 mgd discharge rate are in the range of background levels in Putah Creek and which are above the small concentration necessary to stimulate algae growth without the proposed project. Given the likelihood that phosphorus levels are not controlling algal growth


levels, incremental phosphorus increases suggest that the proposed project would not be inconsistent with state anti-degradation policies. Under the extreme no-flow condition, the streamflow would consist entirely of effluent and there would be no project-related change in potential instream phosphorus conditions.

Based on the above discussion, the WWTP effluent concentration would not change under the proposed project. The project is not likely to result in substantial bio-stimulation of aquatic plants. Therefore, the impact is considered less than significant.


Impact 4.1-14. Electrical Conductivity. Discharges of WWTP effluent under the proposed project would contain EC. EC concentrations in the undiluted WWTP effluent would likely exceed the existing NPDES permit limit, and this exceedance is considered potentially significant. Nevertheless, projected EC concentrations in receiving water would be expected to be fully protective of existing beneficial uses.

Electrical conductivity is a physical measurement that indicates how well water conducts an electric charge and is used to accurately represent the content of charged inorganic dissolved ions (i.e., salts) in water. The principal inorganic anions that contribute to EC include the carbonates, chlorides, sulfates, and nitrates; the principal cations are sodium, potassium, calcium, and magnesium. The sources of dissolved inorganic ions are variable including natural mineral content increases as rainwater passes through mineral soils, evaporative concentration of water from surface waters, agricultural drainage, and specific urban discharges to municipal sewer systems, anti-corrosion additives for municipal water supplies, and water softener discharges. EC measurements are useful in accurately estimating the total dissolved solid (TDS) and salinity – both of which are closely related indicator measurements of the total dissolved inorganic ion content in water.

Inorganic ion content is a concern because elevated levels can impair the taste of drinking water supplies, cause related health effects in persons on limited salt diets, and can cause scale and corrosion problems in plumbing fixtures (U.S. EPA 1986a). In addition, costly treatment processes are required to effectively remove most inorganic ions from municipal water supplies and wastewater treatment. Elevated levels of inorganic ions can also cause plant growth problems if used to irrigate salt-sensitive agricultural crops; most livestock are tolerant of relatively high TDS levels compared to humans (U.S. EPA 1986a). Crop tolerances to EC levels are highly variable, and although the effects of EC on growth and production of specific crops are known, enforceable regulatory criteria for EC in discharges for agricultural uses have not been established. Secondary drinking water MCLs exist to address taste and odor issues for both TDS and EC. These MCLs are specified as ranges of values depending on the duration of exposure.



Phosphorus (ug/L) at Downstream Putah Creek

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6


2002


4.1-11 EXHIBIT Phosphorus in Putah Creek at 1.7 mgd, 2.7 mgd, and 3.8 mgd Effluent Discharge


Permit Compliance

The RWQCB imposed an EC permit limit of 900 µmhos/cm in the current NPDES permit on March 18, 2004. The WWTP discharge does not currently meet the permit limit of 900 µmhos/cm. As a result, the RWQCB adopted a Cease and Desist Order, giving the campus 4 years to comply with the newly adopted effluent limitation. As described in Section 3.4 of this Draft EIR, Project Background, UC Davis has appealed the effluent limit to the SWRCB claiming, among several other considerations, that the use of the 900 µmhos/cm, which is based on a drinking water MCL for aesthetic taste and odor protection, is not applicable to undiluted wastewater because the WWTP effluent would never be permitted to be used as a drinking water source. Putah Creek, which has had EC levels under the adopted limit because of dilution, also does not currently serve as a public water supply. In addition, UC Davis has challenged the application of the lowest value in the range of EC concentrations established by DHS for the secondary MCL. The DHS policy for EC allows a flexible assessment of the drinking water MCL with an upper limit of 1,600 µmhos/cm and short-term excursions of up to 2,200 µmhos/cm. In addition, UC Davis faculty researchers recently conducted an investigation to identify more appropriate and representative EC conditions that should be allowable in Putah Creek based on the beneficial uses that it provides for agriculture (UC Davis 2004a). The report concluded that irrigation water with an EC of 1,100 µmhos/cm is protective for even the most salt-sensitive crops currently or potentially grown downstream of the discharge.

As noted in Exhibit 4.1-1, effluent EC levels have been stable and Table 4.1-4 indicates an average effluent EC of 1,135 µmhos/cm since the WWTP started operations in March 2000. UC Davis does not anticipate that it would be able to meet the newly imposed effluent limit without significant changes in the current and proposed WWTP operation, including treatment technology. The EC concentrations would not be expected to change with the expansion; therefore, the WWTP effluent discharges under the proposed project would exceed the current permit limit if it is upheld by the SWRCB (Table 4.1-4).


While the WWTP effluent may have levels of EC over the RWQCB’s recent permit limit, current EC conditions in Putah Creek downstream of the WWTP discharge do not exceed the applicable secondary MCL for taste and odor protection. Data presented in Exhibit 4.1-1 shows that the mean EC concentrations in Putah Creek have remained fairly consistent during the 2000-2004 period, and concentrations downstream of the WWTP discharge have not exceeded 600 µmhos/cm on average. As shown in the exhibit, concentrations of EC downstream of the WWTP are slightly higher than upstream, and it can be inferred that the WWTP is the source of the increases. Even so, receiving water quality would remain in regulatory-accepted levels.

The mass balance calculation in Table 4.1-8 indicates that the project expansion to 3.8 mgd would result in a maximum downstream EC concentration of 782 µmhos/cm in Putah Creek, which does not exceed the drinking water MCL of 900 µmhos/cm. Exhibit 4.1-12 further shows that the incremental increases in EC as discharge increases from the current 1.7 mgd to



Electrical Conductivity (umhos/cm) at Downstream Putah Creek

0

100

200

300

400

500

600

700

800

900


2002


4.1-12 EXHIBIT Electrical Conductivity in Putah Creek at 1.7 mgd, 2.7 mgd, and 3.8 mgd Effluent Discharge


the permitted 2.7 mgd capacity, and to the proposed 3.8 mgd capacity would not significantly increase the downstream levels of electrical conductivity and downstream levels would be expected to remain below 900 µmhos/cm. The incremental increases are also small relative to the existing background conditions in Putah Creek. As a result, the project would not be inconsistent with state and federal antidegradation policies that allow minor changes to receiving water quality if beneficial uses are not adversely affected.

Under drought conditions, the incremental increases in EC in Putah Creek would be larger than under current conditions as a result of the proposed 3.8 mgd effluent discharge rate and as Putah Creek streamflow decreases, the EC in Putah Creek would approach that of the effluent. However, such low flow conditions are expected to be infrequent under the Accord, and the project-related effects are not expected to be substantially different from current conditions because effluent EC levels are not anticipated to change. Beneficial uses would not be adversely affected. Further, even with no flow in Putah Creek, pure effluent typically would contain EC levels well below the drinking water upper limit of 1,600 µmhos/cm. However, there are no public drinking water intakes downstream of the plant outfall even if Putah Creek were a drinking water source the EC levels following implementation of the proposed project would fall in the upper limit MCL for drinking water. The recent analysis prepared by UC Davis researchers indicate that the EC levels in the WWTP discharge would not adversely impact the quality of water for agricultural uses (UC Davis 2004a). No other beneficial uses would be adversely affected.

From the point of view of NPDES permit compliance, the proposed project would have a potentially significant impact because EC concentrations would exceed the NPDES permit limit if the SWCRB upholds the permit. If the permit levels are increased, the proposed project would not have a significant effect on EC, but that conclusion is based on regulatory decision-makers and is not in the purview of UC Davis. The receiving water EC concentrations would not cause exceedance of applicable regulatory criteria.

▪ Mitigation Measure 4.1-14. Electrical Conductivity. The following mitigation measures have been identified to minimize and avoid the potential continued exceedances of the NPDES permit limit, should the change in the permit not be granted by the SWRCB. Following implementation of one of the mitigation measures identified below, or a combination of one or more of the measures, the impact would be considered less than significant.

< Divert all effluent to the City of Davis: Diverting all of the campus WWTP effluent to the City of Davis (City) wastewater treatment facilities would cease all discharges to Putah Creek. By ceasing all discharges, the WWTP would no longer be governed by the NPDES permit and the associated effluent limitations. In turn, the UC Davis effluent would become part of the City’s effluent and would therefore be subject to the permit limitations contained in the City’s NPDES permit.


The City currently discharges its treated wastewater to either Willow Slough, or to the Conaway Ranch toe drain that leads to a series of wetlands near the Yolo Bypass. Flows from both of the discharge locations available to the city ultimately flow to the Yolo Bypass and Sacramento River. While the City does not currently have a permit effluent limit for electrical conductivity, it is foreseeable that one may be imposed in the future given that wastewater is discharged to a water body. The RWQCB required the city to evaluate salt loading sources and methods to reduce EC discharges from the city’s wastewater treatment plant (City of Davis 2004). The study results identify that EC concentrations in the city’s wastewater discharges (i.e., average in 2002 of approximately 1,300 µmhos/cm) is slightly higher than average concentrations of UC Davis WWTP effluent. Since the city may have electrical conductivity limits imposed in the future, the feasibility of this mitigation measure is speculative. Further, if treated wastewater is no longer discharged to Putah Creek, significant affects could occur to fish resources (see Section 4.2).

< Change in Surface Water Discharge Location: Moving the WWTP effluent discharge location from Putah Creek to the Sacramento River may allow for a modified effluent limit by obtaining a dilution credit for the discharge of its wastewater. Other dischargers on the Sacramento River receive dilution credits. For instance, the Sacramento Regional Wastewater Treatment Plant, which treats 155 mgd, has a 14:1 dilution credit. Because the WWTP effluent exceeds the permit limit by only 100 µmhos/cm on average, the dilution credit necessary would be fairly small and would be achievable given the size of the discharge in comparison to the flow of the Sacramento River.

However, the RWQCB Basin Plan contains a prohibition on the direct discharge of municipal wastes (including wastewater) to the Sacramento River from the confluence of the Feather River to the Freeport Bridge, which is south of the City of Sacramento. The distance between the current WWTP discharge location in Putah Creek and a point south of the Freeport Bridge is considerable. The building of a pipeline from the campus to a point south of the Freeport Bridge would require construction of a 15-mile long pipeline and associated pump stations. An amendment to the Basin Plan allowing a point of discharge between the Feather River and Freeport Bridge is a discretionary decision by the RWQCB, and it is too speculative to determine in this EIR if this would be feasible. If such a pipeline were constructed, it could result in potentially significant impacts to biological and cultural resources, as well as a number of other resource areas (e.g., air quality, water quality, farm land, etc.), depending on its route, and fish resources could be adversely affected by halting discharge to Putah Creek (see Section 4.2).

Another option would be to connect to the City of West Sacramento’s existing outfall, a pipeline that discharges to the Sacramento River near Clarksburg, outside the prohibition zone. The City of West Sacramento will be abandoning the outfall in 2007 after it connects to the Sacramento Regional County Sanitation District’s Lower Northwest Interceptor. The pipeline would be shorter and construction-related effects would be less than described above for a pipeline to the Freeport Bridge area, however, this scenario could also result in potentially significant impacts to biological resources, cultural resources, and other resources.


< Discharge to Evaporation Ponds: Instead of discharging the WWTP effluent to Putah Creek, large evaporation ponds could be constructed with sufficient storage capacity to provide complete evaporation of WWTP effluent during the dry season.

Because of the relatively large volume of WWTP effluent, the amount of land needed for the evaporation ponds would be fairly significant (e.g., up to approximately 1,500 acres) (City of Davis 2004). The RWQCB may require the ponds to be lined to avoid impacts on the electrical conductivity levels of groundwater in the vicinity of the pond to avoid impairment of useable groundwater supplies for drinking water from EC. Significant land area would be needed for ponds, which would likely need to be provided off-campus because of space limitations. Construction of evaporation ponds would likely require conversion of approximately 1,500 acres of agriculture, because this is the only available undeveloped land use in the vicinity. Conversion of 1,500 acres of agriculture would be a significant and unavoidable impact. Other potential impacts could occur to biological resources (e.g., habitat removal, fish resources), groundwater, air quality, etc.

< Agricultural reuse with winter storage in lined ponds: This scenario would be a variation of the evaporation ponds and would include substantial reuse of recycled water during the summer for irrigation of useable agricultural lands or urban landscape. The goal would be to beneficially recycle as much water as possible during the summer to reduce the overall area of ponds required for storage and evaporation.

The large area of land required for large-scale recycled water reuse would likely require utilizing agricultural lands located off-campus because UC Davis’ research-based activities limit the locations where irrigation with wastewater would be acceptable to the academic community. The potential variabiltiy of inorganic and organic constituents in wastewater could create a concern for their potential effects to ongoing research activities on campus. Utilizing off-site properties for irrigation would require long-term participation and cooperation of private agricultural landowners, which inherently poses a risk to the long-term viability of the overall disposal of WWTP effluent, should landowners decide not to participate in the future and/or sell their land. Therefore, the feasibility of this mitigation is speculative.

< Source Control for Campus Cooling Towers and Other Discharges: UC Davis is currently evaluating potential modifications that could be implemented for cooling tower operations that would reduce concentrations and loading of high-EC blowdown water (Brown and Caldwell 2003). In addition, the investigation involves identifying the type and number of water softeners and other on-site water treatment devices, and the potential for providing on-site treatment for these potentially high-EC waste streams. Optimization of these salt load sources could reduce EC levels in the WWTP effluent, however, the anticipated EC reductions would not be sufficient to meet the current NPDES permit limits if the mitigation measure were implemented alone.

Previous investigations of cooling tower blowdown discharges indicated that the complete elimination of these discharges would potentially reduce EC in WWTP effluent discharges by


approximately 50 µmhos/cm. Potential EC reductions from changes in water softening operations have not been investigated, but the volume of these discharges is estimated to be a small fraction of the existing salt load from other sources (i.e., primarily drinking water) and would only provide minor incremental reductions. While optimization of these salt load sources would reduce EC in the WWTP inflow wastewater, such source control would not be expected to sufficiently reduce EC (a reduction of 200 µmhos/cm would be needed) to levels that would comply with the permit limit.

Potential Mitigation Measures for Electrical Conductivity that were Considered but Rejected

Two measures that could potentially be used to reduce effluent EC levels, reverse osmosis technology and development of an alternative source water supply for the campus, were considered but rejected as not practicable for the University and not suitable for current conditions at the WWTP.

Reverse Osmosis Technology: Reverse osmosis technology is a potential alternative to the proposed project identified at length in Chapter 6, Alternatives, and rejected for further analyses as infeasible. Reverse osmosis could potentially be implemented to reduce EC in a portion of the effluent and blended with the remainder of the effluent to meet the 900 µmhos/cm permit limit. Reverse osmosis systems require additional pretreatment filtration to reduce suspended solids. The reverse osmosis process also creates concentrated saline brine. The quantity of brine typically constitutes from 10 to 20% of the original wastewater volume and would require disposal. Disposal of the high-salt content and large volume of brine produced by reverse osmosis is difficult because of potential environmental effects of the brine and high operating costs. Reverse osmosis technology would also be substantially more costly to construct than the proposed project and, because of higher energy use with these systems and maintenance issues, would be substantially more costly to operate. In addition, all of the other treatment process improvements to influent headworks, oxidation ditch, clarifiers, and biosolids handling that are part of the proposed project still would be required. Therefore, this mitigation measure would be infeasible.

Alternative Source Water Supply: Changing or modifying the EC content of the wastewater inflow could reduce the resulting EC levels in WWTP effluent. UC Davis would reduce the amount of water use from groundwater wells with elevated EC levels, or work with the City of Davis to develop an alternative low-EC water supply. The City of Davis and UC Davis have conducted joint investigations into the potential overall improvements to water supply quality (West Yost and Associates [2002], Luhdorff & Scalmanini [2003]). As noted above, the UC Davis deep wells that provide municipal domestic water supply have existing EC concentrations that range from 500 to 700 µmhos/cm. In comparison, EC levels in wells in the intermediate and shallow aquifers (which provide landscape irrigation water) range from roughly 1,100 to 1,200 µmhos/cm. The existing domestic water wells draw from the aquifers in the area with the lowest available EC values. Therefore, optimization of these salt load sources through the development and use of different or new groundwater wells would not be expected to substantially reduce EC in the WWTP inflow wastewater. Potential reductions in


EC levels in the public water supply may be possible if surface water supplies were developed; however, developing new surface water sources would cost over $100 million and would take 10 to 15 years to implement, contingent on numerous legal, financial, and environmental challenges (City of Davis 2002). Therefore, this mitigation measure would be infeasible.

Impact 4.1-15. Coliform Bacteria. Discharges of WWTP effluent under the proposed project would contain coliform bacteria. However, concentrations of coliform bacteria in the undiluted WWTP effluent would not be high enough to exceed permit limits, and concentrations in receiving water would not exceed applicable regulatory guidance criteria. This impact is considered less than significant.

Coliform bacteria represent a large group of bacterial species. Some are endemic to intestinal tracts of warm-blooded animals, while others are commonly found in soils. The total coliform test, and more specific tests for subsets of the coliform group (e.g., fecal coliforms, Escherichia coli, Enterococcus sp.) are used as indicator tests for potential water contamination by human and animal wastes and presence of other pathogenic organisms (e.g., bacteria, protozoa, viruses) that can cause gastrointestinal illness when ingested such as diarrhea, cramps, nausea, or headaches (U.S. EPA 1986a). The Title 22 regulations for total coliform is the standard parameter used at wastewater treatment plants (including the UC Davis WWTP) to ensure the proper performance of the treatment and disinfection facilities. The Basin Plan contains ambient receiving water quality objectives for recreational beneficial use protection that are based on the fecal coliform test. The NPDES permit limits are based on the total coliform counts and thus are entirely protective of ambient water quality conditions regulated by the fecal coliform test.

Permit Compliance

The NPDES permit limits for total coliform bacteria exist as a performance standard to ensure the effectiveness of the WWTP’s tertiary treatment facilities in the removal of pathogens. The effluent limits of 2.2 MPN/100 ml (MPN = most probable number) as a monthly median and 23 MPN/100 ml as a daily maximum require the wastewater to continue to be treated to tertiary standards (filtered). The WWTP has consistently met the existing median monthly permit limit for total coliform ; however, six sampling dates in the period between the start WWTP operations and September 2001 exceeded the daily maximum permit limit. Routine performance of the WWTP ultraviolet disinfection units has maintained compliance with the daily permit limit over the last 3 years. The project expansion would maintain the tertiary level of treatment; the performance history of tertiary treatment systems indicates that properly functioning plants can reliably attain the existing effluent limits. Title 22 requirements for recycled wastewater were derived through performance analysis of such tertiary treatment facilities. The WWTP effluent permit limit of 2.2 MPN/100 ml as a monthly median is the Title 22 standard for unrestricted recreational impoundments. Therefore, it is anticipated that the WWTP effluent would continue to consistently meet the NPDES permit limits.


The Basin Plan contains a bacteria objective of 200 MPN/100 ml for fecal coliform as a median and 400 MPN/100 ml as a maximum, which is designed to protect ambient water conditions


from harmful bacteria. Because fecal coliform measurements represent a subset in the overall group of total coliform organisms, the 2.2 MPN/100 ml total coliform permit limit for the WWTP results in effluent conditions that are inherently protective of the much higher fecal coliform water quality objective for receiving water. Because the WWTP effluent is treated to a tertiary level of treatment that far exceeds levels needed to achieve the adopted water quality objectives, the effluent would not have an adverse impact on pathogen levels in the receiving water under either anticipated routine streamflow conditions or extreme drought conditions.

Based on the discussion provided above, the effluent and receiving water total coliform concentrations would not exceed applicable NPDES permit limits or applicable regulatory criteria for receiving water. Therefore, the impact is considered less than significant.

▪ Mitigation Measure: No mitigation is needed

Impact 4.1-16. Residual Chlorine. Discharges of WWTP effluent under the proposed project would contain residual chlorine. However, concentrations of residual chlorine in the undiluted WWTP effluent would not be high enough to exceed permit limits, and concentrations in receiving water would not exceed applicable regulatory guidance criteria. This impact is considered less than significant.

Residual chlorine refers to the amount of ionized inorganic chlorine ions in the water. Chlorine is a strong oxidizing agent and effective disinfectant of bacteria and many other potential water-borne pathogens and microorganisms. Chlorine is toxic to higher level aquatic organisms (i.e., fish, invertebrates) at low levels (U.S. EPA 1986a). Sources of chlorine include municipal drinking water systems where it is added to maintain disinfecting conditions throughout the distribution system (i.e., desired residual of about 0.5 mg/L), cleaning agents, and swimming pool and spa discharges. Chlorine-based disinfection of effluent is also common in many wastewater treatment plants (including historically in the previous UC Davis WWTP), however, effluent typically must be de-chlorinated if discharged to surface waters. The primary disinfection process for the current WWTP is ultraviolet light and chlorine is only used infrequently during the summer season to clean algae scum buildup in the filtration units. In California, water quality criteria for chlorine for aquatic life protection have not been established in the Basin Plan or CTR, and the applicable drinking water MCL is not relevant to this analysis because it is considerably higher than the low levels that are necessary to protect aquatic organisms. However, the NPDES permit for the UC Davis WWTP includes a discharge limit based on EPA’s national recommended criteria for chlorine for aquatic life protection.

Permit Compliance

The existing effluent limit for chlorine residual is 0.01 mg/L as a 4-day average and 0.02 mg/L as a 1-hour average. The WWTP employs ultra-violet (UV) light disinfection as a substitute for chlorination and dechlorination to minimize the use and release of chlorine. WWTP effluent monitoring data indicate that total residual chlorine levels are consistently less than the detection level of 0.02 mg/L. However, there has been one exceedance associated with cleaning of the WWTP filtration equipment with chlorine-based cleaners where the discharge was not recycled back into the wastewater treatment plant. The current protocol of WWTP


staff is to divert all cleaning rinsate back into the wastewater inflow so that it is routed through full treatment processes. The proposed project would continue the existing treatment approach and is projected to comply with the existing effluent limits for residual chlorine.


The Basin Plan does not contain water quality objective for chlorine. The U.S. EPA aquatic life criteria for chlorine are 0.01 mg/L chronic as a 4-day average and 0.019 mg/L (acute) as a 1-hour average. The existing effluent limits for the WWTP are derived from these U.S. EPA criteria. It is anticipated that the proposed project would continue compliance with these concentrations before discharge to Putah Creek. Therefore, the proposed project would not cause or contribute to adverse impacts in the receiving water associated with chlorine.

Based on the above discussion, the effluent and receiving water residual chlorine concentrations would not cause exceedance of applicable NPDES permit limits or applicable regulatory criteria for receiving water. Therefore, the impact is considered less than significant.


Impact 4.1-17. Turbidity. Discharges of WWTP effluent under the proposed project would contain turbidity. However, turbidity levels in the undiluted WWTP effluent would not be high enough to exceed permit limits, and concentrations in receiving water would not exceed applicable regulatory criteria. This impact is considered less than significant.

Turbidity is a measure of light scattering that occurs in water which is a function of suspended sediment, suspended organic matter, and settleable matter. Reduced water clarity is a concern because it can interfere with algae and plant growth and reduce primary production of food for other organisms, reduce sight-feeding opportunities of fish and other organisms, and may indicate the potential for sedimentation of habitat if the turbidity is caused by settleable matter (U.S. EPA 1986a). Turbidity does not cause human health effects, however, it can interfere with disinfection processes and provide substrate for microbial growth. Applicable NPDES permit conditions are derived from Title 22 reclamation criteria. Ambient receiving waters are subject to Basin Plan objectives that establish the allowable discharge-related change in background turbidity.

Permit Compliance

The NPDES permit effluent limit for turbidity requires the WWTP effluent to not exceed 5 nephelometric turbidity units (NTU) more than 5% of the time in a 24-hour period, and at no time shall it exceed 10 NTU. The daily average limit for turbidity is set at 2 NTU. The campus has reported permit violations related to exceeding the 5 NTU more than 5% time on several recent occasions. At no time has the WWTP effluent exceeded the permit limit of 2 NTU for the average or 10 NTU for a maximum value (Table 4.1-4). As explained in the Tiered IS for the WWTP Expansion Project (Appendix A), the turbidity exceedances were primarily associated with large storm events and high volume discharges of turbid stormwater


into the sanitary sewer system; the turbid influent may come from the animal facilities on campus or stormwater leaks into the sewer system.

The project, which would add sand filters, is expected to address current influent problems related to high turbid flows into the sewer system. As identified in Table 3-2, the filtration improvements are a specific component of the proposed project intended to address the existing need for increased capacity of this critical unit of the overall wastewater treatment plant. The project would expand the capacity of the treatment facility, which would increase the facilities’ ability to handle higher flows during storm events. In addition, the campus intends to continue to optimize the use of chemicals used in the filtration process. Because of the increased capacity created by the project and the optimized use of chemicals to address turbidity during wet weather events, it is projected that the campus would be able to comply with its current permit limit under the proposed project. Such performance is anticipated for well performing tertiary treatment facilities. The Title 22 recycled water requirements, from which the existing effluent limits were derived, were based on performance analysis of tertiary treatment facilities.


The mass balance calculation shows that the increase in the WWTP discharge volume of effluent would not increase levels of turbidity in the receiving water (Table 4.1-8). In fact, the increase in volume would have a slight diluting impact on the receiving water (Exhibit 4.1-13). The Basin Plan objectives for turbidity require that waters be free of changes in turbidity that cause nuisance or adversely impact beneficial uses. The Basin Plan requires the following regarding increases in turbidity attributable to controllable factors:

< Where natural turbidity is between 0 and 5 NTU, increases shall not exceed 1 NTU. < Where natural turbidity is between 5 and 50 NTU, increases shall not exceed 20%. < Where natural turbidity is between 50 and 100 NTU, increases shall not exceed 10 NTUs. < Where natural turbidity is greater than 100 NTU, increases shall not exceed 10%.

As shown in Exhibit 4.1-13, the proposed project would not cause or contribute to violations of the above Basin Plan objectives and would not adversely impact turbidity in the receiving water. The plot of mass-balance analysis results indicates that the increase in the WWTP discharge from the existing 1.7 mgd, to current 2.7 mgd capacity, and up to the proposed 3.8 mgd discharge rate generally is expected to provide a diluting effect to higher background levels in Putah Creek. Under drought conditions, the effluent dataset analysis above indicates that turbidity concentrations would be lower than applicable criteria.

Based on the above discussion, the effluent and receiving water turbidity concentrations would not cause exceedance of applicable NPDES permit limits or applicable regulatory criteria for receiving water. Therefore, the impact is considered less than significant.




Turbidity (NTU) at Downstream Putah Creek

0

5

10

15

20

25

30

35

40

45

50


2002


4.1-13 EXHIBIT Turbidity in Putah Creek at 1.7 mgd, 2.7 mgd, and 3.8 mgd Effluent Discharge


Impact 4.1-18. Endocrine Disruptors. Discharges of WWTP effluent under the proposed project could contain endocrine disrupting compounds (EDCs). However, there are no applicable regulatory criteria for these compounds, and it may be many years before the scientific understanding of their effects is sufficient for the RWQCB to establish permit limits for treated wastewater discharges. Because Putah Creek is not used as a primary drinking water supply downstream of the WWTP discharge, the environmental effects of these compounds, if there are any, would likely not reasonably affect people. Impacts to aquatic resources are not known.

In recent years there has been heightened scientific awareness and public debate over potential impacts that may result from exposure to endocrine disrupting chemicals (EDCs). A recent state-of-the-science assessment by World Health Organization (WHO) defines an EDC as a substance or mixture that alters function of the endocrine system and consequently causes adverse health effects in an intact organism or its progeny (World Health Organization 2002). Endocrine disruption may be described as a functional change that may lead to adverse effects, not necessarily a toxicological end-point. Most EDCs are human-made synthetic chemicals (such as hormones or other drugs) released into the environment unintentionally (e.g., as a trace element in human urine). EDCs may block, mimic, stimulate, or inhibit the production of natural hormones, disrupting the endocrine system’s natural functions. The endocrine system is a combination of glands and hormones that assist in vertebrate reproduction, growth, and development.

Certain drugs, such as birth control pills, intentionally alter the endocrine system. Although there are some known EDCs, many chemicals are termed “suspect,” because there are not enough data to make a conclusive determination of their endocrine disrupting characteristics. Plants, such as soybeans and garlic, produce natural EDCs as a defense mechanism. The U.S. Geological Survey (Barnes et al. 2002) found occurrence of EDCs or potential EDCs to be high in surface waters across the country. The study found 80% of the streams sampled contained at least one of the 95 listed constituents that were tested. Although occurrence frequency was relatively high, measured concentrations were low, usually below drinking water standards for compounds having such standards.

The potential ecological effects of EDCs in the aquatic environment were first reported in the 1990s, including studies that suggested that the presence of natural and synthetic estrogen hormones in wastewater induced vitellogenin production in male fish, which is a protein involved in reproduction and normally only found in females (Desbrow et al. 1998). Similar results were observed with alkylphenolic compounds which are breakdown products of industrial surfactants used in products such as paints, herbicides, and cosmetics (Jobling et al. 1996). Other research has since confirmed that natural and synthetic estrogens are present in effluents in sufficient quantity that they could potentially cause endocrine disruption in some fish (Rodgers-Gray et al. 2000).

Adverse effects have been observed in humans when exposed to endocrine disruptors. However, cases have only been documented in instances of gross exposure, and not at the levels measured in ambient waters. Human exposure and dose response to EDCs in concentrations at the low levels found in the environment is still unknown. The absence of adequate exposure data, especially exposure data during critical development periods, is the


weakest link in determining whether any observed adverse effects in humans and/or fish and wildlife are linked to EDCs. The WHO’s state-of-the-science assessment concludes that “…our current understanding of the effects posed by EDCs to wildlife [including fish] and humans is incomplete.”

The National Toxicology Program (NTP) draft report of the Endocrine Disruptors Low-Dose Peer Review was released for public comment in May 2001 (Federal Register Vol. 66, No. 95, May 16, 2001). As stated in the NTP’s Report, “the focus of this review was on ‘biological change’ rather than on ‘adverse effect’ because, in many cases, the long-term health consequences of altered endocrine function during development have not been fully characterized”. Results of the NTP report found that endocrine disrupting effects were demonstrated when laboratory animals were exposed to low-dose endocrine active agents. Additional recommendations were made regarding research approaches and needed future studies.

Some known EDCs (e.g., PCBs, DDT, chlordane) are regulated via ambient water quality criteria or drinking water standards based on their toxicological and carcinogenic effects. However, there are no applicable water quality criteria for natural and synthetic estrogens or related pharmaceutical chemicals. Based on the current state of knowledge regarding dose-response relationships of EDCs for various organisms at the low levels in which they can occur in surface waters, it is likely to be a number of years, possibly many years, before any such standards are promulgated. The approach in the United States has been that more definitive information needs to be gathered and conclusive research conducted before regulatory measures can be taken. In the most recent version of Title 22, Chapter 3 Recycling Criteria (Section 60320.040 (g) (2), Draft August 2002), DHS has included monitoring requirements for EDCs and pharmaceuticals in recycled water for purposes of groundwater recharge only. However, the requirements do not identify the specific contaminants to be monitored.

Because there are no current regulatory criteria with which to evaluate effluent concentrations of EDCs, permit compliance is not used as a basis of this impact analysis. Based on the above discussion, the effluent and receiving water concentrations of endocrine disrupting compounds are not likely to be causing large-scale adverse effects to aquatic populations. However, because this issue is not well understood and is the subject of ongoing research, a conclusion on significance of the environmental impact cannot be reasonably reached. Section 15145 of the State CEQA Guidelines provides that, if after a thorough investigation a lead agency finds that a particular impact is too speculative for evaluation, the agency should note its conclusion and terminate discussion of the impacts. This is the case here. No impact conclusion can be made based on research of this issue. However, UC Davis will monitor ongoing research and will consult with the RWQCB on further permitting actions, if needed.

▪ Mitigation Measures: No mitigation is required because the impact was determined to be speculative for evaluation.


Impact 4.1-19. Increased Flow in Putah Creek. Streamflow in Putah Creek would incrementally increase by the amount of the treated WWTP effluent discharge. The additional flow would be negligible relative to background winter-season peak flows and thus would not substantially contribute to flooding or erosion. The small incremental increase in summer streamflow conditions would provide a benefit to aquatic habitat. This impact is considered less than significant.

The increase in discharge from existing conditions of approximately 1.7 mgd mean flow in the 2003 dry season to a design capacity of 3.6 mgd ADWF is equivalent to an increase of about 2.9 cfs. Peak daily flows would change from current conditions of about 6.3 mgd to up to 14.0 mgd, equivalent to a 12 cfs increase. These projected increases are small compared to the Putah Creek channel capacity and range of background streamflow. During the winter flood season, the project-related increase in wastewater discharge of 12 cfs during peak hourly conditions is negligible relative to the channel capacity and background flows that can range up to about 19,000 cfs during 50-year flood conditions (U.S. Fish and Wildlife Service 1993). The channel levees currently provide protection from overtopping during 100-year flood events. The small incremental increase would not create a measurable change in either flow or water surface elevation relative to the background flow. During summer conditions when background flows at I-80 are a minimum of 2 cfs subject to the Accord, the mean daily project-related increase in WWTP discharge of about 2.9 cfs would double existing flows. Under drought conditions, the total project-related flow of about 5.6 cfs (3.6 mgd) would maintain aquatic habitat conditions that otherwise might be dry or have near-dry conditions. The project-related flow during summer low-flow conditions is considered a benefit to aquatic habitat by maintaining flow and aeration of the water, providing water for maintenance of riparian vegetation, and maintaining habitat such as pools and riffles. Therefore, the impact is determined to be less than significant.


Impact 4.1-20. Impacts to Groundwater Quality. Streamflow in Putah Creek would incrementally increase by the amount of the treated WWTP effluent discharge. The rate of recharge from the streambed to groundwater would not change. In addition, the discharge of high-quality tertiary treated wastewater would not degrade the quality of shallow groundwater aquifer. This impact is considered less than significant.

Putah Creek is similar to many streams in that, for much of the summer low-flow period, streamflow contributes recharge to the groundwater through percolation of flow through the river bed to the soils below (Gus Yates Hydrologist 2003). During the winter period, the opposite typically occurs; discharge of groundwater from the surrounding soils that are typically saturated from infiltration of rainfall is greater than the recharge of groundwater from streamflow percolation. Therefore, the discharge of tertiary treated wastewater has the potential to alter shallow groundwater quality generally in the summer through the contribution of inorganic and organic compounds that it contains. The quantity of recharge from the streambed to the groundwater is a function of many factors including the level of saturation (i.e., including the groundwater elevation) in surrounding soils, permeability of the streambed for percolating water, the area of streambed that is inundated, and the hydrostatic head (i.e., pressure) in the stream that is available to force water into the soil.


Of the variables described above, the proposed project would only incrementally change the contribution of flow to Putah Creek, which could increase the area of inundation and hydrostatic head through changes to water depth. However, during the summer low-flow period when recharge to the groundwater is likely to occur, the increased contribution of approximately 1.7 cubic feet per second (cfs) (i.e., equivalent to 1.1 mgd resulting from the increased WWTP discharge of 2.7 mgd to 3.8 mgd) would result in a negligible change in depth and surface area relative to the large cross-sectional area of the Putah Creek channel, particularly during winter high flow periods. The Putah Creek channel is a large designated flood control channel of the U.S. Army Corps of Engineers’ overall Sacramento River and Yolo Bypass flood control system designed to accommodate flood flows of approximately 30,000 cfs. The WWTP discharge is negligible relative to the channel flow capacity in Putah Creek. The channel configuration from the Davis area to the Yolo Bypass is relatively level and consists of wide, large pools with little elevation drop. Consequently, the small incremental increase in streamflow under the proposed project would not appreciably change the water surface elevation of the existing low flows during the summer. Therefore, the hydrostatic pressure and surface area of water in the channel, and related rate of groundwater recharge from the channel, is not expected to change appreciably.

In addition, the WWTP produces tertiary treated disinfected wastewater that meets all applicable Title 22 regulations for unrestricted recycled water reuse. The City of Davis’ evaluation of water quality variation among city groundwater wells (most of which are from the shallow/intermediate aquifer) indicates that the weighted mean EC content from all wells (i.e., including low-EC deep wells from the deep aquifer) has ranged from 775 to 983 µmhos/cm in recent years, depending on the season and relative contributions from different wells (City of Davis 2004). UC Davis estimates that groundwater from the shallow/intermediate aquifer averages approximately 1,100 to 1,200 µmhos/cm. The EC content of the WWTP effluent (approximately 1,080 µmhos/cm) is not appreciably higher than the existing quality of shallow groundwater that may be affected by the discharge. The deeper aquifer would not be affected by streamflow because it is confined and isolated from the shallow aquifer by impermeable substrate. Therefore, the small amount of recharge to groundwater that may contribute flow to municipal and private domestic groundwater wells in the area is not considered inconsistent with state and federal antidegradation policies.


4.1.4.5 CUMULATIVE IMPACTS AND MITIGATION MEASURES

The analysis of cumulative impacts has been performed through the examination of the planned second phase of expansion of the UC Davis WWTP facilities that would provide capacity to accommodate up to 4.3 mgd ADWF to serve the campus wastewater demand projected to occur through buildout of the LRDP by approximately 2017. For this analysis, projections of water quality concentrations in Putah Creek resulting from the discharge of effluent at 4.3 mgd were developed using the same methodology employed in the analysis of the proposed project. The results summarized in Table 4.1-10 include predicted mean and maximum receiving water concentrations in Putah Creek downstream from the WWTP discharge.


Impact 4.1-21. Increased Discharge of Wastewater in Putah Creek. Increased discharge of campus wastewater associated with growth under the 2003 LRDP and, discharges associated with other development in the region, could degrade receiving water quality. This impact is considered potentially significant.

With respect to the potential for the WWTP discharge to exceed NPDES permit limits, the proposed full buildout of the WWTP facilities would not change effluent quality because the expansion would only increase the capacity of existing treatment processes. Therefore, effluent quality would not be anticipated to change relative to the existing condition or the first phase expansion to 3.8 mgd. Therefore, with the exception of copper, cyanide, dioxin, and EC, the effluent discharge would be in compliance with permit limits. Because of the WWTP’s history of copper and cyanide exceedences, there is some uncertainty regarding the future reliability of achiving these regulatory criteria. Therefore, impacts associated with these constituents are considered potentially significant. The potential for long-term compliance with the dioxin limit is uncertain and is considered potentially significant. EC concentrations in the WWTP effluent would not change with expansion of the WWTP to 4.3 mgd capacity; therefore, discharge would continue to exceed the 900 µmhos/cm permit limit, and the impact would be considered significant should the SWRCB uphold the current NPDES permit limit.

The results of the mass-balance analyses indicate that receiving water quality effects of the incremental increase in WWTP effluent discharge would be similar to the project-specific impacts previously described. There would be slight increases in the receiving water concentrations of levels of cyanide, nitrate, phosphorus, and EC. None of the incremental increases are of a magnitude to create substantial adverse environmental effects in Putah Creek under typical conditions with Accord flows. Additional incremental increases would occur for some constituents under drought conditions with low streamflow, however, the potential for occurrences of such conditions under the Accord is expected to be infrequent. . The potential for long-term compliance of dioxin concentration in Putah Creek with applicable water quality objectives limit is uncertain.

It is not anticipated that any future projects in the region would discharge effluent to creeks in the Putah Creek watershed. However, the RWQCB determined that several constituents could be of concern in the wastewater discharges and specifically issued a Cease and Desist Order for five constituents: copper, cyanide, iron, and nitrite + nitrite. The 2003 LRDP EIR identified, and UC Davis adopted, Mitigation Measure 4.8-4 (a)-(b) that requires WWTP staff to continue to monitor and modify its pretreatment program, WWTP operation, and/or treatment processes as necessary to comply with WDRs. The mitigation measure also requires continued monitoring specifically targeted at the constituents subject to the Cease and Desist Order and to make appropriate modifications as necessary to the campus pretreatment program to avoid exceedance of permit limits. In combination with Mitigation Measures 4.1-4, 4.1-5, 4.1-7, and 4.1-14 identified in this Draft EIR, implementation of the LRDP mitigation measure would reduce the potential impact to a less than significant level.

▪ Mitigation Measure: Implement LRDP Mitigation 4.8-4(a) and (b) to minimize the potential for degradation of receiving water quality.


LRDP Mitigation 4.8-4(a): The campus shall continue to monitor and modify its pretreatment program, WWTP operation, and/or treatment processes as necessary to comply with WDRs.

LRDP Mitigation 4.8-4(b): The campus shall implement a monitoring program specifically targeted at the following constituents: copper, cyanide, iron and nitrate + nitrite, and make appropriate modifications as necessary to the campus pretreatment program to avoid exceedance of permit limits for these constituents.

▪ Mitigation Measures: No additional mitigation is required.

Table 4.1-11 Mass Balance Analysis Results for Capacity Increase from 2.7 mgd to 4.3 mgd

Pollutants of Concern Units Water Quality Standards or

Criterion Downstream Mean @ 4.3

mgd Downstream Max @ 4.3

mgd

Aluminum µg/L 87 a 131 h 430

Ammonia mg/L-N 0.57 b 0.12 0.28

Arsenic µg/L 10 c 2.5 4.3

Copper µg/L 10.4 d 3.4 5.9

Cyanide µg/L 5.2 e 0.72 8.6

Dichloromethane µg/L 4.7e 28.1 h 28.1 h

Dioxin pg/L 0.013 e 43.7 h 43.7 h

EC µmhos/cm 900 c 661 797

Iron µg/L 300 c, f, g 223 i 807 h, i

Lead µg/L 3.0 d 0.28 1.73

Mercury µg/L 0.05 e 0.01 0.02

Nitrate + Nitrite mg/L-N 10 c 9.0 59 j

pH Standard Unit 6.5-8.5 f 8.1 8.5

Phosphorus, Total mg/L-P NA 0.74 1.5

Turbidity NTU Narrative f 16 64 Source: Larry Walker Associates based on UC Davis WWTP discharge monitoring data. a. 2002 USEPA Ambient Criteria b. EPA Ambient Water Quality Report, based on pH of 8.6 c. State and Federal drinking water MCLs d. CTR based on hardness of 119 mg/L (95th percentile) e. California Toxics Rule (CTR) f. Basin Plan g. Applicable Water Quality Standard is in dissolved form h. Values exceed applicable objective as result of elevated background Putah Creek concentration; effluent actually

reduces the concentration in Putah Creek. i. Samples analyzed as total recoverable concentration. j. Single outlier nitrate+nitrite value of 104 mg/L skews results. NA = Not Available

Campus WWTP Expansion Draft EIR EDAW University of California, Davis 4.2-1 Biological Resources

4.2 BIOLOGICAL RESOURCES

4.2.1 INTRODUCTION

This section describes the biological resources including common vegetation and wildlife resources, fisheries and aquatic biological resources, sensitive biological communities, and special-status species that are known to occur, or have potential to occur, within the project area. Information presented in this section for terrestrial biological resource issues is based on the 2003 LRDP EIR and reconnaissance-level field surveys conducted by EDAW biologists on June 21 and 24, 2004. The purpose of the surveys was to characterize common biological resources present at the project site and to document areas that could support special-status species and sensitive habitats.

This chapter evaluates both project-specific and cumulative impacts to terrestrial biological resources associated with the proposed conversion of the existing emergency wastewater storage basin to a third drying basin and to the beneficial uses of Putah Creek and downstream waters that could result from operations-related changes to water quality and physical habitat associated with the effluent discharge. Mitigation measures to reduce or avoid potential impacts also are defined herein. Other potential construction- and operations-related biological impacts associated with the other facility improvements for the WWTP expansion were fully addressed in the LRDP EIR or were determined in the Tiered IS not to require further analysis.


Habitat types found on the campus are discussed in the 2003 LRDP EIR (pp. 4.4-1 to 4.4-8) and illustrated in Figure 4.4-1 (p. 4.4-3). As discussed in the 2003 LRDP EIR and Tiered IS, the campus occupies approximately 5,300 acres and the WWTP project site occupies an approximately 16.5-acre site in the south campus area. The campus is located in a region that is composed primarily of agricultural lands that include remnant riparian areas and urban areas. Habitat types on campus can be classified as Agricultural Lands (including Cropland/Pasture, and Orchard/Vineyard), Valley Foothill Riparian Woodland, Ruderal/ Annual Grassland, Open Water Ponds, Riverine, and Urban Landscaping/Developed. The WWTP site does not include land used for agricultural purposes, but is in an agricultural area, and the northwest corner of the site is bordered by Prime Farmland that is currently used for campus teaching and research. The site is located approximately 0.5 mile north of the Putah Creek riparian corridor. The undeveloped portions of the WWTP site generally consist of disturbed ruderal areas and bare soil, urban landscaping/developed areas, and open water pond habitats.

Special-status species, which include plants and animals that are legally protected or that are otherwise considered sensitive by federal, state, or local resource conservation agencies and organizations, that potentially inhabit the campus are discussed in the 2003 LRDP EIR (pp. 4.4-8 to 4.4-16) and tabulated in Table 4.4-2 (LRDP EIR, pp. 4.4-22 to 4.4-30). Many of the special-status species are not expected to occur on the campus or have a low potential for occurrence because the habitat elements they require either were never present or are no

EDAW Campus WWTP Expansion Draft EIR Biological Resources 4.2-2 University of California, Davis

longer found on the highly managed and modified lands associated with the campus and adjacent agricultural and urban development. This WWTP site is located in an area of the campus that includes potential habitats for a selected subset of species identified in the 2003 LRDP EIR. The WWTP site contains considerably less potential for habitat than the local vicinity as a result of the disturbed conditions onsite and WWTP operations.

The expansion of WWTP facilities included in the proposed project would involve earthwork and construction activities that were fully evaluated in the 2003 LRDP EIR. The current WWTP facilities occupy approximately 11 acres of the site, and the proposed upgrades would occur within or immediately adjacent to areas occupied by WWTP facilities. The proposed project would also increase the discharge of treated effluent to Putah Creek, which offers riverine and wetland habitats. The instream effects to aquatic resources (i.e., fisheries) of the proposed WWTP expansion were generally addressed in the 2003 LRDP EIR, and the analysis is specifically addressed and updated in this EIR based on the most recent setting and proposed project information.

4.2.2.1 PROPOSED DRYING BED SITE

The following discussion focuses on biological resources associated with an existing 0.8-acre emergency wastewater storage basin at the UC Davis WWTP site that is proposed for conversion to a biosolids drying bed. Reconnaissance-level surveys of the proposed drying bed site were conducted by EDAW biologists on June 21 and 28, 2004. The purpose of these site visits was to assess the potential for presence of sensitive biological resources and to note common plant and wildlife species observed.

Vegetation

The existing emergency storage basin was initially constructed in 2000. The storage basin site was an uplands pasture prior to 2000. The current habitat assemblage has developed over the last 4 years. The bottom of the existing emergency storage basin is characterized by a dense cover of weedy annual and perennial grasses and forbs, most of which are classified as hydrophytes. Species observed include common nutsedge (Cyperus eragrostis), curly dock (Rumex crispus), Bermuda grass (Cynodon dactylon), common spikerush (Eleocharis macrostachya), and rabbitsfoot grass (Polypogon monspeliensis). The lowest part of the basin was covered by standing water with a dense cover of algae and seedlings of aquatic herbs on the June survey.

Riparian tree saplings are scattered throughout the basin, with a more continuous narrow band of riparian vegetation present around its lowest part. Trees observed include approximately 30 cottonwood (Populus fremontii) saplings ranging in height from 6 to 12 feet, approximately 30 willow (Salix laevigata, S. lasiandra) saplings up to 8 feet high, and approximately 20 salt cedar (Tamarisk sp.) saplings up to 6 feet high.

The steep banks of the basin are characterized by weedy non-native grasses and forbs, including tumbleweed (Salsola tragus), milk thistle (Silybum marianum), prickly lettuce (Lactuca serriola), shortpod mustard (Hirschfeldia incana), perennial pepperweed (Lepidium latifolium),


birdsfoot trefoil (Lotus corniculatus), Canada thistle (Cirsium arvense), horseweed (Conyza canadensis), and panicle willowweed (Epilobium brachycarpum).

The area immediately surrounding the basin includes a dirt road and stockpiled rocks and is mostly devoid of vegetation. Adjacent land uses include other WWTP facilities, campus buildings and research facilities, the UPRR right-of-way, and ruderal/grassland habitat.

Wildlife

Wildlife diversity in the basin is expected to be relatively low because of the disturbed nature of the site and the developed nature of the surrounding area. The basin contains low-quality habitat that may support small mammals, reptiles, amphibians, and birds that easily adapt to environments subject to human disturbance. Common species observed or expected in the basin include black-tailed jackrabbit (Lepus californicus), western fence lizard (Sceloporus occidentalis), American crow (Corvus brachyrhychos), and killdeer (Charadrius vociferus).

Sensitive Habitats

Sensitive habitats include those that are of special concern to resource agencies, or that are afforded specific consideration through CEQA, Section 1602 of the California Fish and Game Code, and/or Section 404 of the federal Clean Water Act (CWA). The emergency storage basin in the project area may be considered a sensitive habitat because it provides wetland functions and values.

Special-status Plants

Two special-status plants have been recorded in the vicinity of the project area: rose mallow (Hibiscus lasiocarpus), a California Native Plant Society (CNPS) List 2 species (plants considered rare or endangered in California, more common elsewhere), and valley sagittaria (Sagittaria sanfordii), a CNPS List 1B species (plants considered rare and endangered in California and elsewhere). Both species are associated with wetland habitats. Neither species was observed and neither is expected in the basin because of the disturbed condition of the project area.

Special-status Wildlife

Based on the 2003 LRDP EIR, the following terrestrial special-status wildlife species are known to occur in the project vicinity: valley elderberry longhorn beetle (Desmocerus californicus dimorphus), northwestern pond turtle (Emys marmorata), giant garter snake (Thamnophis gigas), California tiger salamander (Ambystoma californiense), Swainson’s hawk (Buteo swainsoni), and burrowing owl (Athene cunicularia). Of these, only the northwestern pond turtle could potentially occupy the project site. Valley elderberry shrubs are located adjacent to the UPRR tracks west and north of the project site; however, none are within 100 feet of the proposed drying bed site and would not be disturbed during project construction. The project site and surrounding developed WWTP facilities do not provide suitable foraging area for Swainson’s hawks. Burrowing owls, or evidence of their past presence, were not observed in the project


area. The WWTP drying bed site is located away from Putah Creek and does not lie within the floodplain of the creek; therefore, the proposed drying bed site does not provide habitat for any of the listed fish species (see fish resources for discussions of special status fish).

Northwestern Pond Turtle

Northwestern pond turtle is a California species of special concern. This species is present along lower Putah Creek. Pond turtles could occupy the detention basin because it supports water; however, the basin provides low-quality habitat for pond turtle. There are no basking sites, and adjacent upland areas do not provide suitable nesting habitat for this species. Therefore, the northwestern pond turtle is not expected occur.

4.2.2.2 AQUATIC RESOURCES

This section incorporates by reference the discussions on the hydrology of Putah Creek provided on pages 4.1-1 to 4.1-6 of the 1996 Draft EIR for the Wastewater Treatment Plant Replacement Project (Jones & Stokes Associates 1996). In addition, the 2003 LRDP EIR, pp. 4.4-1 (including Figure 4.4-1) provides discussions pertaining to the regional and local setting, and pp. 4.8-18 pertains to the surface water quality of Putah Creek. These discussions also are incorporated into this chapter by reference. Additional regional and local setting information is provided below.

Putah Creek begins at an elevation of approximately 4,700 ft mean sea level (msl) in the Mayacamas Mountains near the summit of Mount Cobb in Lake County. Putah Creek flows eastward for approximately 80 miles through Napa County to the Yolo Bypass (near its former terminus in the Putah Sinks) and ultimately to its terminus at the Sacramento River at an elevation of approximately 10 ft msl. Putah Creek’s total drainage area is approximately 600 square miles. Streamflow in Putah Creek is regulated by the Solano Project, which includes Lake Berryesa, a 1.6 million acre-foot (af) reservoir formed by Monticello Dam, and Lake Solano, formed by the Putah Creek Diversion Dam (PDD). The PDD is located at an elevation of approximately 125 ft msl. Both of these dams create impassible barriers to fish migration.

The UC Davis WWTP discharges treated effluent directly into Putah Creek approximately 7 miles upstream from the East Toe Drain/Yolo Bypass, and about 16 miles downstream of the PDD.

Instream Flows

Historic instream flows in Putah Creek are summarized in Table 4.2-1.

In May 2000, the Putah Creek Water Accord (Accord) was signed, thereby resolving a lawsuit by the Putah Creek Council, City of Davis, and UC Davis against the Solano County Water Agency (SCWA), Solano Irrigation District (SID), and other Solano County entities seeking permanent environmental flows in lower Putah Creek. This settlement resulted in minimum seasonal flow requirements for lower Putah Creek (Table 4.2-2) and improved fisheries habitat conditions that favor resident and anadromous salmonids in the 23-mile stretch of Putah Creek downstream of the PDD.


Table 4.2-1 Summary of Flows at or Near Putah Creek Diversion Dam

Before and After Construction of the Solano Project Flow (cfs)

Variable Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Pre-Project (1934-1956) 1

Max 3,957 6,468 3,506 2,729 452 156 64 32 21 45 807 5,110

Med 794 1,075 736 281 125 42 7 5 6 6 37 296

Min 45 67 151 50 17 7 2 0 2 1 3 9 Post Project (1971-1981, 1985-1990) 1

Max 1,239 2,239 3,403 2,020 51 43 43 34 36 20 50 85 Med 38 41 33 46 43 43 43 34 20 20 25 25

Min 25 18 26 45 33 33 33 26 16 15 26 25 1 Adapted from U.S. Fish and Wildlife Service (1993); years post-project data selected to reflect periods similar to

available pre-project conditions. cfs = cubic feet per second Source: Putah Watershed Management Plan (EDAW 2004)

The Accord sets minimum mean daily and instantaneous flow requirements for non-drought and drought years to protect native resident fishes and to enhance creek conditions for use by anadromous salmonids (Table 4.2-2). In addition to the minimum flow requirements presented in Table 4.2-2, the Accord requires additional supplemental flows intended to protect the aquatic resources of lower Putah Creek.

The supplemental flow requirements to protect spawning and rearing of resident native fish species include:

1. Three-consecutive-day pulse flows (i.e., temporary large releases from upstream reservoir storage) from the PDD to occur between February 15 and March 31 of every calendar year, with flows equal or greater than:

a. 150 cfs for the first 24 hours, b. 100 cfs for the second 24 hours, and c. 80 cfs for the third 24 hours.

2. Maintenance of mean daily flows equal to or greater than 50 cfs at the Interstate 80 (I-80) Bridge for the 30 days that follow the three-day pulse flows described in #1 above; and

3. In every year, flows shall be gradually reduced over a 7-day period following the 30th day of 50 cfs spawning flows described in #2 above.


Table 4.2-2 Minimum Monthly Instream Flow (in cubic feet per second [cfs]) Requirements Set by the Putah Creek Water Accord for Lower Putah Creek Monitoring Locations During Drought and Salmonid

Rearing Flows During Non-Drought Years

Non-Drought Year Rearing Flows Drought Year Flows1

Immediately downstream of PDD

I-80 Bridge Immediately

downstream of PDD I-80 Bridge Month

Mean Daily

Instantaneous Mean Daily

Instantaneous

Old Davis Bridge to RM 0* Mean

Daily Instantaneous

Mean Daily

Instantaneous

Oct 20 18.0 5 4.5 15 13.5 2 1

Nov 25 22.5 10 9.0 25 22.5 2 1

Dec 25 22.5 10 9.0 25 22.5 2 1

Jan 25 22.5 15 13.50 25 22.5 2 1

Feb 16 14.4 15 13.50 16 14.4 2 1

Mar 26 23.4 25 22.50 26 23.4 2 1

Apr 46 41.4 30 27.00 46 41.4 2 1

May 43 38.7 20 18.00 33 29.7 2 1

Jun 43 38.7 15 13.50 33 29.7 2 1

Jul 43 38.7 15 13.50 33 29.7 2 1

Aug 34 30.6 10 9.0 26 23.4 2 1

Sep 20 18.0 5 4.5

Maintain a continuous

flow of surface water

15 13.5 2 1 1 Drought year exists when Lake Berryessa storage is less than 750,000 acre-feet on April 1. * RM = river mile; RM 0 = Putah Creek confluence with western boundary of the Yolo Bypass

The requirements for supplemental flows for anadromous salmonids include:

1. Beginning on November 1 of each calendar year, and continuing through December 15, maintain a mean daily flow of at least 5 cfs and an instantaneous flow of at least 2 cfs at the Putah Creek/East Toe Drain confluence;

2. Beginning sometime between November 15 and December 15, maintain mean daily flows of at least 50 cfs and a pulse flow of at least 45 cfs for 5 consecutive days at the Putah Creek/East Toe Drain confluence;

3. Beginning on the 6th day following initiation of the 50 cfs pulse flows described in #2 above, and continuing each day thereafter through March 31, maintain a mean daily flow of at least 19 cfs and an instantaneous of at least 14 cfs at I-80; and

4. Beginning on April 1 of each calendar year, and continuing through May 31, maintain a mean daily flow of at least 5 cfs and an instantaneous flow of at least 2 cfs at the Putah Creek/East Toe Drain confluence.


Drought year flows occur when total storage in Lake Berryessa is less than 750,000 af as of April 1 and continuing through the following year. Whenever the drought year release and instream flow requirements are in effect for two consecutive years, then during the next year thereafter, the non-drought year requirements apply and remain in effect for an entire period from April 1 through March 31, unless total storage in Lake Berryessa on April 1 is less than 400,000 af. If the drought year requirements are ever in effect for three or more consecutive years, then the non-drought year requirements apply and remain in effect for an entire period from April 1 through March 31 in the first subsequent year during which total storage in Lake Berryessa on April 1 exceeds 400,000 af.

Temperature

The temperature of a water body dictates, in large part, the type of fish species that inhabit and reproduce in that water body. Therefore, a summary of Putah Creek temperatures in the vicinity of the WWTP discharge is provided, along with a characterization of the WWTP effluent temperature, which affects temperatures downstream of the WWTP.

Table 4.2-3 provides summary statistics for the WWTP temperature for the period March 2000 through June 2004. The effluent temperature averages from 65EF in the winter to 78EF during the summer.

Table 4.2-3 UC Davis WWTP Effluent Temperature Statistics (EF)


Count 95 94 126 125 135 116 87 99 87 101 86 82

Mean 66 66 69 70 74 77 77 77 76 73 69 66

Median 65 66 70 70 74 78 77 77 76 73 69 66

Minimum 60 62 62 64 67 70 73 66 71 67 64 57

Maximum 74 75 76 80 95 90 81 90 82 80 74 73 Source: Daily data reported in the Discharger Self-Monitoring Reports for March 2000 through June 2004.

Exhibits 4.2-1 and 4.2-2 illustrate the historic Putah Creek temperature patterns at the R1 (immediately upstream of the WWTP discharge) and R2 (immediately downstream of the WWTP discharge) monitoring stations. The creek exhibits a typical seasonal temperature pattern, with downstream temperatures similar to upstream temperatures.

Fish Species of Putah Creek

Evaluating potential impacts to fish resources requires an understanding of fish species using Putah Creek, their respective life histories, life-stage-specific environmental requirements, and seasonal distributions within the creek. This information is discussed below. Specific life histories are provided for fall-run chinook salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss), which are two special-status species of primary concern.


EXHIBIT

Source: Weekly data reported in the Discharger Self-Monitoring Reports for March 2000 through June 2004 2002

Putah Creek Temperature Measured at the R1 Monitoring Station (Upstream of WWTP Discharge) 4.2-1

44464850525456586062646668707274767880828486

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov DecDate

Tem

pera

ture

(ºF

)

20002001200220032004


EXHIBIT Putah Creek Temperature Measured at the R2 Monitoring Station (Downstream of WWTP Discharge) 4.2-2

44464850525456586062646668707274767880828486


Tem

pera

ture

(ºF

)

2000

2001

20022003

2004

Source: Weekly data reported in the Discharger Self-Monitoring Reports for March 2000 through June 2004 2002


Available documentation indicates that 39 fish species have been observed in lower Putah Creek downstream of the PDD between 1991 and 2002 (Table 4.2-4; Moyle et al. 2003). The fish species assemblage is comprised of 13 native species and 26 introduced species. In addition, two hybrids of introduced centrarchids have been documented in lower Putah Creek. Native fish species generally occur in the greatest abundance within the first 4 miles downstream of the PDD, comprising 99% of the overall fish species community along that reach (Moyle et al. 2003), while introduced fish species dominate the reach beginning 10 miles downstream of the PDD (Exhibit 4.2-3, Exhibit 4.2-4; Moyle et al. 1998). The most abundant native fish species in the 10 miles of lower Putah Creek below PDD include Sacramento pikeminnow (Ptychocheilus grandis), Sacramento sucker (Catostomus occidentalis), and tule perch (Hysterocarpus traski).

A native species exception to the species distribution descriptions provided above occurs for the Sacramento blackfish (Orthodon microlepidotus), which are found primarily downstream of the City of Davis (Moyle 2002). The most abundant introduced fish species in the lower Putah Creek include bluegill (Lepomis macrochirus), green sunfish (Lepomis cyanellus), largemouth bass (Micropterus salmoides), western mosquitofish (Gambusia affinis), and inland silverside (Menidia beryllina) (Moyle et al. 2003). Smallmouth bass (Micropterus dolomieui) provide a popular sport fishery in the lower reaches of Putah Creek.

Eight special-status fish species have been documented in lower Putah Creek in recent decades. Central Valley Evolutionarily Significant Unit (ESU)1 steelhead, discussed further below, a species listed under the federal Endangered Species Act (ESA) as threatened, historically spawned in Putah Creek, but there have been no confirmed observations of steelhead in recent decades.

Central Valley fall-run chinook salmon, discussed further below, a federal ESA Candidate Species, uses Putah Creek seasonally for spawning and rearing. Spawning populations of chinook salmon have increased in the years following the implementation of Accord flows. Redd2 surveys conducted in 2003 indicate that approximately 70-80 adult chinook salmon spawned in lower Putah Creek, perhaps the largest run documented to date (Moyle and Crain 2003). Life histories for chinook salmon and steelhead are provided below because they are anadromous fish species that use the creek in a different manner than do the creek's resident native and introduced species. For life histories of other resident fish species, see Moyle (2002).

1 An Evolutionarily Significant Unit or "ESU" is a distinctive group of Pacific salmon or steelhead generally defined by geographic spawning location and/or the seasonal timing of spawning migrations. 2 Redds are spawning nests made by fish in gravel, especially salmon or trout.


Table 4.2-4 Fish Species Collected in Putah Creek Downstream of the PDD Between 1991 and 2002

Family Common Name Scientific Name Native Fish Species Catostomidae (Suckers) Sacramento sucker Catostomus occidentalis Centrarchidae (Sunfishes) Sacramento perch Archoplites interruptus Cottidae (Sculpins) Prickly sculpin Cottus asper Riffle sculpin Cottus gulosus Cyprinidae (Minnows) California roach Hesperoleucus symmetricus Hitch Lavinia exilicauda Sacramento blackfish Orthodon microlepidotus Sacramento pikeminnow Ptychocheilus grandis Embiotocidae (Surfperches) Tule perch Hysterocarpus traski Gasterosteidae (Sticklebacks) Threespine stickleback Gasterosteus aculeatus Petromyzontidae (Lamprey) Pacific lamprey Lampetra tridentata Salmonidae (Trout and Salmon) *Chinook salmon Oncorhynchus tshawytscha *Rainbow trout Oncorhynchus mykiss Introduced Fish Species Atherinidae (Silversides) Inland silversides Menidia beryllina Centrarchidae (Sunfishes) Black crappie Pomoxis nigromaculatus Bluegill Lepomis macrochirus Green sunfish Lepomis cyanellus Largemouth bass Micropterus salmoides Pumpkinseed Lepomis gibbosus Redear sunfish Lepomis macrolophus Smallmouth bass Micropterus dolomieui Warmouth Lepomis gulosus White crappie Pomoxis annularis Clupeidae (Herrings) American shad Alosa sapidissima Threadfin shad Dorosoma petenense Cyprinidae (Minnows) Common carp Cyprinus carpio Fathead minnow Pimephales promelas Golden shiner Notemigonus chrysoleucas Goldfish Carassius auratus Red shiner Cyprinella lutrensis Gobiidae (Gobies) Yellowfin goby Acanthogobius flavimanus Ictaluridae (Bullhead Catfishes) Black bullhead Ameiurus melas Brown bullhead Ameiurus nebulosus Channel catfish Ictalurus punctatus White catfish Ameiurus punctatus Moronidae (Striped Basses) Striped bass Morone saxatilis Percidae (Perches) Bigscale logperch Percina macrolepidotus Poeciliidae (Livebearers) Western mosquitofish Gambusia affinis Salmonidae (Trout and Salmon) *Brown trout Salmo trutta Source: Moyle et al. 2003 * coldwater species


EXHIBIT

Source: Moyle (2003) - based on observations downstream of the Putah Diversion Dam during the period 1991-2002. WWTP is located about 16 miles downstream from the Putah Diversion Dam.

Relative Abundance of Introduced and Native Fish Species - Lower Putah Creek 4.2-3

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

Miles Downstream of the PDD

Rel

ativ

e A

bu

nd

ance

IntroducedSpecies

NativeSpecies


EXHIBIT

Migratory

Migratory

Migratory

Year-round distribution

Seasonal or fluctuating distribution

Occasional

Note: Anadromous salmon, steelhead, and lamprey are likely to have more fluctuating distributions than what is shown here.

6

Sacramento Blackfish

Hitch

Tule Perch

Prickly Sculpin

Threespine Stickleback

Sacramento Sucker

Sacramento Squawfish

California Roach

Pacific Lamprey

Chinook Salmon

Steelhead Trout

Rainbow Trout

Riffle Sculpin

Typical Distribution pattern of native fishes in lower Putah Creek 1980 to 1995 4.2-4

Source: Moyle et al. 1998

Div

ersi

on D

am

I-505

Has

broo

k C

ross

ing

Rus

sell

Ran

ch

Stev

enso

ns B

ridge

APO

Pic

nic

WW

TP O

utfa

ll

Mac

e Bl

vd

Yolo

Byp

ass


0 2.5 3 4 9 10 13.5 16 23 19

Miles Downstream From Putah Creek Diversion Dam


Pacific lamprey (Lampetra tridentata), a federal Species of Concern, were first observed spawning in lower Putah Creek at a gravel restoration site a short distance downstream of the PDD. Lampreys are a specialized form of aquatic vertebrate that is eel-like in appearance, and lacks the jaws and paired fins of true fishes. Pacific lampreys spend the predatory phase of their life in the ocean, where they attach to the sides of other fishes, feeding on their body fluids. Adults typically move into freshwaters to spawn in the spring. Eggs are laid in a crude nest and embryos generally hatch within about two to three weeks. The newly hatched young (called ammocoetes) spend a short time in the gravel, then swim up into the water column where they are washed downstream to suitable areas characterized by sand and mud substrates. The ammocoetes burrow tail first into the soft substrate, where they exist as filter feeders, consuming detritus and algae, for 5-7 years. Upon undergoing physiological transformations to prepare themselves for entering the ocean, they emigrate to the ocean, typically under high-flow events during the winter and spring period of the year (Moyle 2002). Pacific lamprey can tolerate warmer water temperatures and lower water clarity than anadromous salmonids. Based on their life history requirements, the proposed project would not adversely affect this species’ use of Putah Creek.

Sacramento perch (Archoplites interruptus), a federal Species of Concern and California Species of Special Concern under the California Endangered Species Act (CESA), were considered extant from Putah Creek in the 1980s and 1990s; however, they were re-introduced in 1997 (Moyle et al. 2003). Historically, Sacramento perch were found throughout the Central Valley, at elevations below about 100 m. The only populations today that represent continuous habitation within their native range are those in Clear Lake and Alameda Creek. They seek slough, slow-moving river, and lake habitats. Sacramento perch are adapted to tolerate low water clarity, high water temperatures, and high salinities and alkalinities (Moyle 2002). As such, the effects of the proposed project would not adversely affect this species, should it be present in lower Putah Creek.

It is believed that Putah Creek no longer supports populations of the remaining special-status fish species: Sacramento splittail (Pogonichthys macrolepidotus), Sacramento-San Joaquin roach (Lavinia symmetricus symmetricus), hardhead (Mylopharadon conocephalus), and green sturgeon (Acipsenser medirostris), all of which are listed as federal Species of Concern and/or California Species of Special Concern.

Chinook Salmon

Central Valley fall-run chinook salmon occur in Putah Creek. Chinook salmon are anadromous, meaning that adults live in marine environments and return to their natal freshwater streams to spawn. Juveniles rear in freshwater for a period of up to 1 year until smoltification (i.e., a physiological preparation for survival in marine environs) and subsequent ocean residence.

Central Valley fall-run chinook salmon are important commercially and recreationally. They are designated as California Species of Special Concern and are Candidate Species for listing under the federal ESA. On September 16, 1999, the National Oceanic and Atmospheric


Administration (NOAA) Fisheries determined that listing was not warranted for the Central Valley ESU. However, the ESU is designated as a candidate for listing because of concerns over specific risk factors. The ESU includes all naturally spawned populations of fall-run chinook salmon in the Sacramento River and San Joaquin River basins and their tributaries, east of Carquinez Strait.

In general, adult fall-run chinook salmon migrate into Putah Creek from mid-October through December following the removal of flashboard dams and the Accord pulse flows, with immigration generally peaking throughout the Central Valley from mid-October through November. The majority of spawning occurs within a few miles downstream of the PDD where suitable size spawning gravels are present. Redd surveys conducted in 2002 (Moyle 2003; EDAW 2004) found no chinook salmon redds, nor suitable gravel in the stretch of Putah Creek extending from I-80 downstream to Old Davis Road. Fall-run chinook salmon emigrate as post-emergent fry, juveniles, and as smolts after rearing in their natal streams for up to 6 months. Based on the creek’s current thermal regime, the vast majority of fall-run chinook salmon emigration is believed to be completed by May, annually. This is evidenced, in part, by the supplemental rearing and outmigration flows for the period through April 15 as recommended by the Putah Creek Council in the court trial for the Accord (Moyle et al. 1998). Outmigrants remain in the Sacramento-San Joaquin Delta (Delta) for variable lengths of time before ocean entry.

Myrick and Cech (2001) have compiled the most comprehensive review of temperature effects on Central Valley chinook salmon to date. Chinook salmon eggs can survive at temperatures ranging from 35EF to 62EF, but highest survival rates occur between approximately 45EF and 50EF. Survival of juvenile chinook salmon (and steelhead) under high temperatures is a function of acclimation temperature and exposure time. The reported chronic upper lethal limit for Central Valley chinook salmon is approximately 77EF, although temperatures approaching 84EF may be tolerated for short exposures. Growth of juvenile chinook salmon occurs at temperatures ranging from 46EF to 77EF, with maximum to near-maximum growth rates reached at approximately 56EF to 68EF (Myrick and Cech 2001).

Steelhead

Steelhead trout, the anadromous form of rainbow trout, historically spawned in Putah Creek. There have been no documented observations of steelhead in Putah Creek in recent decades. In 1998, NOAA Fisheries listed the Central Valley ESU as threatened under the federal ESA. The decrease in the population was largely because of habitat loss resulting from the construction of dams that separated historical spawning and rearing areas.

Adult steelhead reside in the ocean for 1–4 years before returning to their natal stream to spawn. In Central Valley streams, steelhead spawning migrations typically occur as streamflows rise between December and April. Peak spawning activity typically occurs between February and April. Steelhead are iteroparous (capable of spawning more than once), spawning up to four times before dying. Adult fish may spawn annually but often skip a year between spawns. Steelhead eggs incubate for 3–4 weeks at 50–59°F before hatching, and fry


emerge from the gravel 2–3 weeks later. Juvenile fish spend between 1 and 3 years in freshwater before smoltification and ocean entry.

Although steelhead have not been documented in Putah Creek, potentially suitable spawning and rearing habitats (e.g., gravels, water temperatures) exist within the creek between the PDD and the City of Winters, upstream of the project area. If steelhead were to use Putah Creek, the project area would only be within a migration corridor (UC Davis 2003).

Steelhead eggs survive at water temperatures ranging from 35.6EF to 59EF, but highest survival rates occur between approximately 44.6EF and 50EF (Myrick and Cech 2001). Juvenile steelhead have a relatively wide thermal tolerance range compared with juvenile chinook salmon. The reported critical thermal maximum (i.e., acute) temperature tolerances for American River steelhead range from 81.9EF for fish acclimated at 51.8EF, to 85.3EF for fish acclimated at 66.2EF (Myrick and Cech 2001). The reported upper incipient lethal (i.e., chronic) temperature limit for Central Valley steelhead ranges between about 77EF and 79EF. (The temperature of UC Davis WWTP effluent is reported in Table 4.2-3 and Exhibits 4.2-1 and 4.2-2 illustrate Putah Creek temperature patterns.)


4.2.3.1 TERRESTRIAL BIOLOGY

The 2003 LRDP EIR (pp. 4.4-16 – 4.4-19) fully describes all of the federal and state regulatory requirements and laws that apply to the proposed project. Brief summaries of the laws and regulations that may be relevant to the proposed project are described below.

< California or federal Endangered Species Act: Listed or proposed species, and Species of Special Concern, include those plants and animals that can be afforded protection through CESA/ESA. Additional special-status species subject to review under CEQA are identified through the following programs: California Native Plant Protection Act; and plants on the CNPS List 1B (rare, threatened, or endangered in California and elsewhere) or CNPS List 2 (rare, threatened or endangered in California but more common elsewhere).

< Section 404 of the CWA: U.S. Army Corps of Engineers (Corps) permit program for activity that involves any discharge of dredged or fill material into “waters of the United States,” including wetlands. The Code of Federal Regulations (CFR) 328.3(a)(8) states that waste treatment systems, including treatment ponds or lagoons designed to meet the requirements of CWA which otherwise meet the criteria of a wetland, are not Waters of the United States. Further, wetlands that are considered “isolated” (i.e., that are not hydrologically connected to waters of the United States) are not subject to Corps jurisdiction.

< Porter Cologne Water Quality Control Act: The RWQCB is responsible for water quality protection for “waters of the State” through the Porter Cologne Water Quality Control Act. Waters of the State are defined as surface waters or groundwater, including saline waters,


within the boundaries of the state. The RWQCB issues waste discharge requirements (WDRs) for projects that could adversely affect waters of the state.

< California Fish and Game Code Section 1602 – Streambed Alteration Agreements: All diversions, obstructions, or changes to the natural flow or bed, channel, or bank of any river, stream or lake in California that supports wildlife resources are subject to regulation by California Department of Fish and Game (DFG), pursuant to Section 1602 of the California Fish and Game Code.

4.2.3.2 AQUATIC RESOURCES

This section also incorporates by reference the discussions in the 2003 LRDP EIR (pp. 4.8-25 to 4.8-27) pertaining to the UC Davis WWTP National Pollutant Discharge Elimination System (NPDES) Permit (NPDES Permit No. CA0077895, Order No. R5-2003-003), and pp. 4.4-16 to 4.4-18 pertaining to the federal ESA, CWA, California ESA, and Fish and Game Code Section 1602. Additional information pertaining to the regulatory setting is provided below.

Management of anadromous fish is the responsibility of NOAA Fisheries, whereas management of non-anadromous fish and other aquatic biological resources in the project area is the responsibility of the USFWS and the DFG. The DFG acts as state trustee for aquatic species. These three agencies, either independently or in collaboration with other state and federal agencies, implement numerous fish management and restoration plans and initiatives. The majority of these plans and initiatives are focused on the Sacramento River, its primary tributaries, and the Delta, which are used by anadromous fishes.

Key local, state, and federal fish restoration plans are listed and briefly discussed below.

Anadromous Fish Restoration Program of the Central Valley Project Improvement Act

This program has an overall target of doubling the natural production of Central Valley anadromous fish relative to the average levels attained during the period 1967-1991 (Sections 3046(b)(1) of the Central Valley Project Improvement Act [CVPIA]; Public Law 102-575). Section 3046(b)(1) is referred to as the Anadromous Fish Restoration Program (AFRP), administered by the USFWS. Putah Creek is not specifically addressed in this program.

Steelhead Restoration and Management Plan for California

In 1996, DFG published the Steelhead Restoration and Management Plan for California (McEwan and Jackson 1996). This plan identifies water diversions and associated structures, high water temperatures, pollution, channelization projects, flood control projects, bank protection projects, and water export operations as the primary impacts to production and survival of steelhead and other anadromous fish in the mainstem Sacramento River. Putah Creek is not specifically addressed in this plan.


Ecosystem Restoration Program Plan of the CALFED Bay-Delta Program

The mission of the CALFED Bay-Delta Program is to develop a long-term comprehensive plan that will restore ecosystem health and improve water management for beneficial uses of the Bay-Delta system. The program addresses problems in four resource areas: ecosystem restoration, water quality, system integrity, and water supply reliability. Programs to address problems in the four resource areas will be designed and integrated to fulfill the CALFED mission.

The foundation of the Ecosystem Restoration Program Plan (ERPP) is restoration of ecological processes that are associated with streamflow, stream channels, watersheds, and floodplains. These processes create and maintain habitats essential to the life history of species dependent on the Delta. In addition, the ERPP aims to reduce the effects of stressors that inhibit ecological processes, habitats, and species.

The ERPP states that the vision for the Putah Creek Ecological Management Unit is that “…native resident fish will be protected and enhanced by improving stream channel characteristics, instream habitat, streamflows, fish passage, riparian habitat, and spawning gravel recruitment and by screening unscreened diversions.” Key fisheries-related restoration targets for the Putah Creek Ecological Management Unit being proposed by the ERPP include:

< Construction of a network of channels within the Yolo Bypass to connect the Putah Creek Sinks to the Delta;

< More closely emulate natural seasonal patterns by providing additional flows, when available from existing water supplies;

< Restore gravel recruitment to meet the needs of spawning fish, maintain natural stream channel meanders, and bar formation where consistent with flood protection and adjoining land uses, and match existing rates of downstream displacement;

< More closely emulate natural stream channel configuration, consistent with flood control requirements;

< Increase overbank flooding potential to floodplains, where feasible and consistent with flood protection, to support a desirable vegetation succession process;

< Increase the area of flooding to the active floodplain during the wet season, where feasible and consistent with flood protection;

< Establish a desirable level of floodwater retention potential by expanding, where feasible and consistent with floodplain protection, the floodplain area of the Yolo Bypass, lower Cache Creek, and lower Putah Creek, and by developing off-channel water storage facilities;


< Restore riparian vegetation, where possible, to provide cover and other essential habitat requirements for native resident fish species and wildlife;

< Maintain and improve existing freshwater fish habitat and essential fish habitat through the integration of actions described for ecological processes, habitats, and stressor reduction or elimination;

< Screen all diversions in the Yolo Bypass channels and sloughs;

< Improve fish passage between the Delta and spawning grounds in the upper watersheds;

< Protect, enhance, and restore natural gravel recruitment within the active floodplain and remnant gravel pits;

< Reduce populations of invasive non-native plant species that compete with the establishment and succession of native riparian vegetation to help reestablish native riparian vegetation in floodplains, increase shaded riparian aquatic (SRA) cover for fish, and increase habitat values for riparian-associated wildlife;

< Reduce predation and competition on native fish species;

< Restore and maintain water quality in the Putah Creek Watershed; and

< Prevent adult salmon and steelhead stranding in the Yolo Bypass during their upstream migration.

Such restoration actions, when implemented over the next few decades, are expected to increase Putah Creek fish populations, including salmonid populations, over existing conditions.

Restoring Central Valley Streams: A Plan for Action

In 1993, DFG published Restoring Central Valley Streams: A Plan for Action (Reynolds et al. 1993), which was developed to address the protection of anadromous fish habitat in Central Valley streams. This plan identified 12 priorities for improvement of anadromous fish habitat in the Sacramento River. In addition, the plan identified six priorities for administrative actions to improve Sacramento River anadromous fish habitat. Putah Creek is not specifically addressed in this plan.

UC Davis Habitat Conservation Plan

UC Davis is planning to prepare a Habitat Conservation Plan (HCP) to address all special-status species issues associated with campus development, programs, and operations. Mitigation measures identified in this chapter could be incorporated into any future HCP, as appropriate.




The following standards of significance are taken from the 2003 LRDP EIR and are based on

Appendix G of the State CEQA Guidelines. As stated in the 2003 LRDP EIR, an impact is

considered significant if the proposed project would:

< Result in a substantial adverse effect, either directly or through habitat modifications, on any species identified as a candidate, sensitive, or special-status species in local or regional plans, policies, or regulations, or by DFG or USFWS;

< Result in the “take” (defined as kill, harm, or harass) of any listed threatened or endangered species or the habitat of such species;

< Result in a substantial adverse effect on any riparian habitat or other sensitive natural community identified in local or regional plans, policies, regulations or by the DFG or USFWS;

< Result in a substantial adverse effect on federally protected wetlands as defined by Section 404 of the CWA (including, but not limited to, marsh, vernal pool, coastal, etc.) through direct removal, filling, hydrological interruption, or other means;

< Interfere substantially with the movement of any native resident or migratory fish, or wildlife species or with established native resident or migratory wildlife corridors, or impede the use of native wildlife nursery sites; or

< Conflict with any local applicable policies protecting biological resources.


Terrestrial Biology

The analysis for this project is consistent with the methods used in the 2003 LRDP EIR. In addition, site-specific evaluation of the potential impacts to biological resources were based on the reconnaissance-level field surveys of the site, experience with wetland assessment, and expertise in dealing with state and federal laws and requirements. The WWTP was constructed and became operational in March 2000, and the emergency storage basin was constructed in October 2000. Therefore the WWTP and storage basin were part of the existing conditions at the time the 2003 LRDP EIR was prepared. Consequently, this project-specific analysis is being conducted to focus specifically on the potential biological impacts of converting the 0.8-acre emergency storage basin into an additional concrete lined sludge drying bed.


Aquatic Resources

The standards of significance defined for Biological Resources in the 2003 LRDP EIR (pp. 4.4-19 and 4.4-20) that are specifically relevant to biological resources including fish populations, communities, and other aquatic resources are used here. This tiered EIR further refines and adds to these standards of significance to best determine potential impacts to aquatic resources of Putah Creek and downstream waters that may occur from implementing the project, while maintaining consistency with the standards used in the 2003 LRDP EIR. Application of these standards of significance to findings determined from technical assessments was used to make impact significance determinations. Effects of the proposed project on fish or other aquatic resources would be significant if the proposed project would:

< Cause changes to receiving water quality or physical habitat conditions of sufficient magnitude and frequency to adversely affect keystone aquatic species’ long-term population levels, thereby adversely affecting the integrity of Putah Creek’s ecology;

< Result in a substantial adverse effect, either directly or through habitat modifications, on any aquatic species identified as a candidate, sensitive, or special status species in local or regional plans, policies, or regulations, or by the DFG, USFWS, or the NOAA Fisheries;

< Result in “take” of any ESA-listed aquatic species, as defined in Section 9 of the federal ESA or Section 2081 of the CESA;

< Interfere substantially with the movement of any native resident or migratory fish species, thereby resulting in adverse effects on the population; or

< Conflict with any local applicable policies protecting aquatic biological resources.

Because the existing WWTP became fully operational in March 2000, the effluent data set used for the purposes of this impact assessment consists of the period April 2000 to the present. Effluent data collected before all plant upgrades coming on-line in April 2000 are not representative of effluent quality expected under the proposed project condition, and thus were not used for impact assessment purposes. Because the quality of the effluent under the project condition is expected to be similar to the post-upgrade effluent quality (i.e., current effluent quality), post-upgrade effluent data and bioassay testing results were used to assess the potential for discharges under the project condition to affect aquatic resources in Putah Creek and downstream water bodies.

Section 4.1, Hydrology and Water Quality, of this Draft EIR provides a detailed discussion and assessment of compliance with water quality standards in the receiving waters and expected NPDES permit compliance under the project condition. This chapter uses these findings to determine the number of constituents requiring evaluation for impacts to aquatic life. If water quality objectives/California Toxics Rule (CTR) criteria would be met under the project condition, and these objectives/criteria are adequately protective of aquatic biological resources of the receiving waters, then no impact discussion for such constituents is warranted in this


chapter because no impacts would be expected from these constituents. However, if water quality objectives/CTR criteria defined for the protection of freshwater aquatic life have been periodically exceeded in the receiving water or current NPDES permit limits defined to protect aquatic life have been periodically exceeded because the last plant upgrade came on-line in April 2000, an impact assessment is provided. Secondly, if applicable water quality objectives/CTR criteria and permit limits are consistently met, yet these limitations may not be adequately protective of the aquatic biological resources of Putah Creek, or no limitation is currently in-place for a constituent of concern for aquatic life, then an impact assessment for that constituent also is provided herein. Finally, certain constituents are specifically addressed, regardless of historic/projected compliance, if they are prone to substantial changes because of the project and are critically important regarding the protection of aquatic biological resources.

Based on this methodology, constituent-specific impact assessments are provided below for the following (in alphabetical order):

< Aluminum < Copper < Cyanide < Dissolved Oxygen < Lead < pH < Temperature < Turbidity

In addition, the potential for the project to impact aquatic biological resources via effects on the following also is assessed in this chapter:

< Additive and synergistic toxicity; < Fish migration; < Riparian habitat; < Instream flows; and < Eutrophication.

In its ambient water quality criteria documents, the U.S. EPA states that freshwater aquatic organisms and their uses should not be affected unacceptably if the recommended criteria are not exceeded more than once every 3 years, on the average. To this end, the U.S. EPA states that: “…all adverse effects are not necessarily unacceptable, but that pollution should not be allowed to subject aquatic communities to long-term or regular short-term adverse effects. All dramatic adverse effects are certainly unacceptable….. EPA recognized that the chemical and ecological field data summarized in Chapter 1 [of EPA’s Technical Support Document] suggest that successive excursions well above the criteria would be needed to cause severe impacts…. If the criteria are set appropriately, a marginal excursion might be expected to have little or no measurable impact, and little or no time period needed for recovery.” (U.S. EPA 1991b). “EPA thus expects the 3-year return interval to provide a very high degree of protection.” (U.S. EPA 1991a). This U.S. EPA guidance was applied in interpreting the


significance of objective/CTR criteria and permit limit exceedances observed in the post-upgrade effluent data set evaluated.

The focus area for this assessment is Putah Creek from the WWTP effluent discharge location downstream to the Yolo Bypass, because water quality and habitat-related effects of the project would be greatest here. If the project would not substantially affect the aquatic biological resources of Putah Creek – the direct receiving water – it is further concluded that it would not adversely impact aquatic biological resources in downstream water bodies (e.g., East Toe Drain, Yolo Bypass, Sacramento River), where the project effects on water quality would be less because of in-channel dilution, uptake, and constituent breakdown within these larger perennial flowing water bodies.


Impacts Adequately Analyzed in the LRDP EIR or Impacts Not Applicable to the Project

The 2003 LRDP EIR addressed the potential effects at a programmatic level on aquatic biological resources of buildout under the 2003 LRDP, including expansion of the WWTP, but did not evaluate the effects of the proposed project at a project-specific level. The Tiered IS further identified the following potential environmental impacts of the proposed project that would not likely be significant and need not be further analyzed in the EIR: (1) conflict with any local policies or ordinances protecting biological resources; and (2) conflict with the provisions of an adopted Habitat Conservation Plan, Natural Community Conservation Plan, or other approved habitat plan. In addition, the Tiered 1S addressed terrestrial biology effects associated with most WWTP improvements, and the analyses below focus on effects associated with the emergency storage basin site and aquatic resources. Impact 4.4-9 of the 2003 LRDP EIR addressed the effects on riverine aquatic macroinvertebrates of increased Putah Creek flow from the WWTP discharge, and is incorporated herein by reference. This impact is further evaluated in this analysis to address the incremental project-related changes.

Terrestrial Biology

Impact 4.2.1 Impacts to Special-status Species. A number of special-status species have been documented in the vicinity of the proposed drying bed site. However, no special-status species are expected on the site, and no suitable habitat for these plants and animals would be affected by the proposed project. This impact is considered less than significant.

The two special-status plants that have previously been recorded in the vicinity of the project area, rose mallow and valley sagittaria, are not expected to occur in the basin due to its fairly disturbed nature. Furthermore, these species were not observed during the site visit conducted as part of the project evaluation. The site visit was conducted at the appropriate time for these species to have been present and identifiable.

As discussed in the environmental setting discussion above, no special-status wildlife species are expected to occur in the project area because there is no suitable habitat to support special-status species. Northwestern pond turtle could occur in the project area because of its


proximity to Putah Creek and because the basin supports water. However, northwestern pond turtle is not expected to be present because the project area supports low-quality habitat for this species, there are no basking sites, and areas immediately adjacent to the project area do not support suitable breeding habitat for this species. Therefore, although the LRDP EIR determined that 2003 LRDP impacts to northwestern pond turtle are potentially significant (and provided mitigation measure 4.4-7 to mitigate the impact to a less-than-significant level), because the proposed project site does not support suitable habitat for this species, the WWTP expansion would have a less-than-significant impact.

▪ Mitigation: No mitigation is required.

Impact 4.2.2 Impacts to Wetlands. Implementation of the proposed project would result in the conversion of a 0.8-acre emergency wastewater storage basin to a concrete-lined drying bed. This impact is considered potentially significant because the basin provides wetland functions and values, and it may be considered a jurisdictional wetland.

The storage basin, as described in the Project Description in Chapter 3, and depicted in Exhibit 3-4, was constructed in a ruderal upland portion of the WWTP site to provide emergency wastewater storage for the WWTP. The basin is an element of the WWTP that is necessary to store wastewater in emergency situations to prevent water quality violations. The basin has been used once because its excavation for emergency storage. Since that time, the basin has captured rainfall and limited stormwater runoff from the adjacent undeveloped area as well as limited amounts of leakage from pipes transporting water between the other storage basins on-site. The emergency storage basin has become vegetated with wetland vegetation and is characterized by wetland hydrology and hydric soils. The basin does not have an outlet.

The Corps’ definition of Waters of the United States specifically excludes “wastewater treatment systems, including treatment ponds or lagoons designed to meet the requirements of CWA” (33 CFR 328.3(a)(8)). The emergency storage basin would therefore appear to not be within the Corps’ jurisdiction under Section 404 of the CWA. Further, because it is an isolated wetland, even if it were not excluded by the CWA definition, it is likely the Corps would not consider the basin to be a water of the United States.

Because the emergency storage basin is characterized by wetland vegetation, hydrology and soils and provides a limited amount of wetland functions and values, it may be considered a “water of the state” subject to RWQCB jurisdiction under the state Porter Cologne Act and/or subject to DFG jurisdiction as a “sensitive habitat”. Therefore, conversion of the emergency wastewater storage basin to a concrete lined drying bed is considered a potentially significant impact.

The 2003 LRDP EIR adopted Mitigation Measures 4.4-8 (a)-(c) to reduce potentially significant wetland impacts of the 2003 LRDP (Impact 4.4-8) to a less-than-significant level. However, LRDP Mitigation Measures 4.4-8 (a) and (b) are not applicable to this project’s conversion of the storage basin because the basin is exempt from Corps jurisdiction under Section 404 of the


CWA, and delineation, verification, and mitigation pursuant to those measures are not required.

However, the following LRDP mitigation measure adopted for the 2003 LRDP EIR shall be implemented to determine the basin’s jurisdictional status pursuant to RWQCB and DFG jurisdictions:

▪ Implement LRDP EIR Mitigation Measure 4.4-8(c).

4.4-8(c). The campus shall obtain the necessary Corps, DFG, and RWQCB permits prior to filling or other adverse modifications of any verified jurisdictional water of the U.S., or alteration, filling or modification of the channel, bed or bank of Putah Creek, South Fork of Putah Creek, Arboretum Waterway or any other natural drainage regulated under Section 1600 of the DFG code.

The campus shall consult with and obtain the necessary permits from DFG and RWQCB prior to filling the basin. If, based on these consultations, it is determined that the basin is considered a “Water of the State”, or is regulated under Section 1602 of the Fish and Game Code, UC Davis shall develop a mitigation plan for conversion of the basin in cooperation with DFG and/or RWQCB. This conversion may include habitat recreation in the area of the site, elsewhere on the campus or offsite, or may include other, mutually agreed upon measures. Implementation of this mitigation measure would reduce this impact to a less-than-significant level.

▪ Mitigation Measures: No additional mitigation is required.

Aquatic Resources

The discussion below addresses each of the chemical constituents of concern. It is acknowledged that the discussion is complex. However, because potential adverse effects to fish are related to their exposure and how the exposure is associated with individual chemical constituents, the complex nature of the discussion is required to understand, support, and substantiate the conclusions.

Impact 4.2-3. Aluminum. Discharges of treated effluent under the project condition would contain aluminum. At sufficiently high levels, aluminum can cause toxicity to aquatic life; hence, this is a constituent of concern regarding impacts to aquatic life in Putah Creek. However, concentrations of aluminum in the undiluted WWTP effluent would not be high enough to cause toxicity to aquatic life. This impact is considered less than significant.

California does not currently have an adopted water quality objective or criteria for aluminum, applicable to Putah Creek. The U.S. EPA published a technical guidance document in 1988 (U.S. EPA 1988) that provides a review of the scientific literature pertaining to aluminum toxicity to aquatic life, and recommends criteria for states’ consideration. It is not until states adopt such recommended criteria as part of their water quality standards that the criteria become regulatory. Nevertheless, the NPDES permit for the WWTP contains an effluent aluminum limitation (87 µg/L, 4-day average; 750 µg/L, 1-hr average) taken directly from U.S.


EPA’s aluminum criteria document. This limit was included in the permit under the auspices of implementing the Basin Plan’s narrative toxicity objective.

Under the project condition, effluent aluminum concentrations are expected to remain essentially equivalent to what they have been because the plant was upgraded in 2000. Since 2000, effluent aluminum concentrations have remained below 87 µg/L, with one exception (refer to Section 4.1, Hydrology and Water Quality, Table 4.1-4). The one exceedance of the permitted 87 µg/L aluminum effluent limitation that occurred since 2000 (an effluent concentration of 141 µg/L aluminum on February 20, 2004) was the result of adding alum to control effluent turbidity during a storm event. This operational practice has been modified to avoid such occurrences in the future. The frequency of exceedance of the aluminum permit limitation of 87 µg/L observed in the data set evaluated is less than the once in 3-year frequency deemed acceptable by U.S. EPA.

It also should be noted that U.S. EPA’s aluminum criteria document is often misinterpreted, regarding its recommendations for waters of different chemistries. Aluminum toxicity to freshwater aquatic life is affected by the receiving water pH and total hardness (as mg/L CaCO3). In this regard, U.S. EPA recommends the following (U.S. EPA 2003a):

“As has been previously pointed out, EPA’s 1988 chronic aluminum criterion, 87 µg/L, is based on two tests, one with brook trout and one with striped bass, at low hardness (10–12 mg/L) and low pH (6.5–6.6). This value is considered to be necessary for protecting waters having such low hardness and pH. However, this value is expected to be overly protective when applied to waters of moderate hardness and pH. Many such waters are known to exceed this value while fully attaining the goals of the Clean Water Act.

Based on data for a diversity of species tested at hardness in the range of 45–220 mg/L and pH in the range of 6.5–8.3, the 1988 document notes that the chronic criterion would be determined to be 750 µg/L.”

Based on the monthly water quality grab samples for effluent and the upstream monitoring station (R1), the lowest total hardness value in effluent during the period January through December 2002 was 110 mg/L, and the lowest R1 hardness was 148 mg/L. In addition, the lowest recorded post-upgrade effluent pH was 6.5 and the lowest upstream receiving water (R1) pH was 7.6. From these data, it can be concluded that Putah Creek downstream of the discharge would never have a pH of 6.5 concurrently with a total hardness less than 45 mg/L. Hence, based on U.S. EPA’s above-cited recommendation regarding aluminum and the water quality of the creek, even the one permit exceedance identified above on 2/20/04 (141 µg/L) would pose no risk of toxicity to aquatic life in Putah Creek. This is because the applicable aluminum criterion for Putah Creek, based on its total hardness and pH levels, would be 750 µg/L – both above and below the WWTP discharge.

Based on the discussion provided above, the effluent aluminum concentrations expected to occur under the project would not cause aluminum toxicity to aquatic life in Putah Creek or downstream waters.



Impact 4.2-4. Copper. Discharges of treated effluent under the proposed project would contain copper. At sufficiently high levels, copper can cause toxicity to aquatic life; hence, this is a constituent of concern regarding impacts to aquatic life in Putah Creek. However, concentrations of copper in the undiluted WWTP effluent would not be high enough to cause toxicity to aquatic life. This impact is considered less than significant.

Copper is a concern for its ability to act as a toxin to aquatic organisms. Hence, aquatic toxicity is avoided and minimized by ensuring that copper concentrations in water and wastewater are less than applicable water quality criteria. Copper concentration measurements are normally indicated as either total or dissolved, with dissolved forms having been derived from filtered water samples and thus representing copper associated with either very small particles or entirely dissolved ions. Copper ions in the aquatic environment can exist in four oxidation states, or “chemical species” including: Cu0, Cu1+, Cu2+, and Cu3+, with the free cupric ion (Cu2+) being the most toxic. Although the cupric ion is the ionic form generally encountered in water, it is generally less available for uptake by aquatic biota in the presence of organic chelators, carbonates, and other constituents that bind with the free ion through the process of complex formation (Eisler 1997). Because of the propensity for the toxic cupric ion (Cu2+) to complex or bind with other organic and inorganic constituents, it accounts for less than 1% of the dissolved copper in freshwater. The major chemical complexes of copper in most freshwaters are Cu(CO3)2

-2 and CuCO3 (Boyle 1979). These carbonate complexes are much less toxic than other copper complexes and, of course, the free cupric ion (Hall et al. 1997, Diamond et al. 1997, Meador 1991).

Copper toxicity to aquatic biota is related primarily to the dissolved cupric ion (Cu2+) and possibly to some hydroxyl complexes (Eisler 1997). The availability of these toxic forms to aquatic organisms is largely what dictates the relative degree of toxicity that will occur upon exposure to a given concentration of total copper. Copper’s biological availability (or “bioavailability”) is modified by water quality variables in aquatic systems. pH, total hardness and alkalinity, dissolved and suspended organic materials, salinity, and turbidity have significant influences on the complexes that dissolved cupric ions will form and, therefore, the relative bioavailability and toxicity associated with a given concentration of total copper (Eisler 1997, Hall et al. 1997, Diamond et al. 1997, Meador 1991).

The CTR promulgated the copper criteria as a function of water hardness to reflect empirical data showing that toxicity of copper decreases as hardness increases. Unlike hardness, empirical relationships for other parameters (e.g., organic carbon, sulfate, sodium, alkalinity, and pH) known to affect copper’s bioavailability were not fully developed or were unknown at the time the copper criteria were promulgated in the CTR. Therefore, to account for the effects of these other parameters and promulgate copper criteria that are appropriate for the conditions under which they are applied, the U.S. EPA provided for the adjustment of the dissolved criteria through a water-effect ratio (WER). The WER is applied as a simple multiplier, as shown by the general form of the dissolved metals criteria below:

Dissolved Metal Criterion = WER * CF * metal-specific equation (fn[hardness]) where:


CF = total-to-dissolved conversion factor fn[hardness] = metal-specific empirical equation in CTR

A WER is a measure of bioavailability and toxicity of a metal in the receiving water divided by the same measure in laboratory waters used to derive the criteria. The CTR applies a default WER equal to 1.0, meaning that receiving waters of the state are regulated as if their characteristics (and thus effects on bioavailability) are equivalent to the laboratory waters upon which the criteria are based, unless a site-specific WER has been determined. If a site-specific WER is 3, for example, then the toxicity in the site water is 3 times lower than that of the water used to derive the criterion, or, in other words, it takes three times as much metal in the site water to have the same toxic effect as in the water used to derive the criterion. Thus, to provide the same level of protection as that intended by the criterion, the criterion is adjusted for the characteristics of the site water by the WER factor, which in essence is a “multiplier.” If the unadjusted criterion in this example were 10 µg/L, the WER adjustment for the site water would result in a criterion of 30 µg/L (i.e., the initial criterion adjusted via multiplying by the value of the WER, 10 µg/L x 3 = 30 µg/L). The current permit limit for copper is equivalent to the CTR hardness-based criteria, and assumes a WER of 1.0.

Seven exceedances of the effluent copper limitation occurred during the period of assessment (post-March 2000), with concentrations on these occasions ranging between 16 and 29.3 µg/L. Although effluent copper concentrations occasionally exceed the permit limitation, which assumes a WER of 1.0, bioassay results (see Impact 4.2-9. Additive or Synergistic Toxicity) do not indicate signs of copper toxicity. This is attributed to the presence of organic and inorganic binding materials in the effluent tying up the copper, making it unavailable for uptake by aquatic organisms.

The bioassay finding discussed above for this WWTP, despite copper effluent concentrations exceeding criteria (with an assumed WER of 1.0), has been demonstrated at numerous WWTPs across the nation. Numerous investigations have found that biologically treated effluents contain sufficient amounts of organic and inorganic matter (e.g., total organic carbon, particulate matter, and humic, fulvic, and amino acids) to complex with or “tie-up” free copper ions, thereby reducing or eliminating copper bioavailability and thus toxicity at copper concentrations similar to and even above those observed in the WWTP effluent (Hall et al. 1997). Hall et al. (1997) reports copper WERs ranging from 15 to 64 for four water bodies receiving municipal effluent discharges under low dilution conditions. U.S. EPA’s streamlined guidance for deriving copper WERs (EPA-822-R-01-005) implemented a conservative change in calculating each sample WER, which would modify the WERs cited above by Hall et al. (1997) downward, with the expected range being about 5-20. Based on these and other findings discussed in their paper, Hall et al. (1997) concluded that biologically treated effluents eliminate copper toxicity with significant additional complexing capability in reserve.

This effect has been demonstrated locally by the author of this chapter, Roberson-Bryan, Inc., by conducting copper WER testing for another tertiary treatment plant located in the Central Valley. The initial WER determined for the tertiary treated effluent, in 2003, was 9.5. A


copper effluent WER determined in 2001 for a WWTP in the Santa Ana Region (Region 8) was 4.37. Based on the lowest measured effluent hardness of 110 mg/L (as CaCO3), a WER of 3 or greater would mean that all effluent copper concentrations measured post-upgrade would comply with the CTR copper criteria, when adjusted for site-specific conditions. Based on the findings from Hall et al. (1997) and WER studies conducted in the State, it is reasonable to believe that the WWTP copper WER is at least 3.

Based on the information presented above, the current copper concentrations observed in the WWTP effluent are not expected to be present in biologically available forms and thus would not be expected to cause toxicity to aquatic life in Putah Creek, upon its discharge to the creek, regardless of creeks flows and thus dilution ratio. More frequent (daily) monitoring has been implemented for copper, along with changes in the types of coagulants used for filtration aids that have resulted in more effective control and response to influent copper levels. Finally, in an abundance of caution, WWTP staff intends to further refine plant operations and continue to pursue ongoing source control efforts to further reduce copper effluent concentrations. Due to the potential for exceedences of the copper limit contained in the NPDES permit, Mitigation Measure 4.1-4 (refer to Section 4.1, Hydrology and Water Quality) would be implemented to continue monitoring influent and effluent copper levels and adjust corrective measures if copper levels exceed the permit limit. The mitigation provides further assurance that effluent copper levels would be maintained at low levels.

Based on the discussions provided above, the effluent copper levels expected to occur under the proposed project condition pose a negligible risk for toxicity to receiving water aquatic life.


Impact 4.2-5. Cyanide. The project could cause elevated levels of cyanide in Putah Creek, downstream of the discharge. This impact is considered potentially significant.

The post-upgrade effluent data set evaluated shows two exceedances of the CTR chronic cyanide criterion of 5.2 µg/L, and no exceedances of the 1-hr acute criterion of 22 µg/L. The NPDES permit contains these same limitations, because no dilution credit is granted in the permit. The source(s) of cyanide to the plant causing the two exceedances of 21 µg/L on 7/7/01 and 19 µg/L on 6/10/02 is unknown. The infrequent occurrence at the levels noted above suggests a periodic source input rather than an in-plant production issue.

Available data indicate that the acute criterion has never been exceeded, but because the chronic exceedances cited above are based on analytical measurements taken for a single day, rather than a mean concentration from composite effluent samples collected and analyzed for four consecutive days (the chronic criterion is applicable as a 4-day average concentration), it remains uncertain whether the WWTP effluent has ever actually exceeded the chronic criterion. Likewise, it is uncertain whether the chronic cyanide CTR criterion would ever be exceeded in the receiving water under the project condition. Based on this uncertainty, the potential for cyanide to cause toxicity to aquatic life, and the low dilution ratios that can occur during some months of the year and during drought conditions, periodic cyanide levels in the


effluent on the order of 20 µg/L constitute a potentially significant impact to aquatic life in Putah Creek.

▪ Mitigation Measure 4.2-5: Implement a phased evaluation/source control measure to address effluent cyanide levels as specified in Mitigation Measure 4.1-5.

If violations do occur it is assumed that UC Davis will be successful at determining and controlling the source. Therefore, implementation of this mitigation would reduce the impact to a less-than-significant level.

Impact 4.2-6. Dissolved Oxygen. The project could alter the seasonal dissolved oxygen levels downstream of the discharge, but not to the degree that fish would be adversely affected. This impact is considered less than significant.

Discharges from WWTPs can cause downstream reductions in dissolved oxygen levels, depending upon effluent quality, dilution ratios, receiving water velocity and associated re-aeration coefficients, and instream oxygen production/use rates via photosynthesis/respiration. Insufficient dissolved oxygen levels can cause adverse effects to aquatic life.

U.S. EPA’s ambient water quality criteria for dissolved oxygen (U.S. EPA 1986b) are more refined than those of the Basin Plan and, therefore, are used as the basis for this scientific assessment. U.S. EPA’s ambient water quality criteria for dissolved oxygen are presented in Table 4.2-5 and quoted below. The resident fish species using the UC Davis reach of the creek, where the plant discharge is located, constitute a “warmwater” fish community. However, the creek provides habitat on an intermittent basis for coldwater fish species that are migrating upstream or emigrating downstream to the Delta. Consequently, the applicable criteria for Putah Creek are the warmwater values and coldwater values for “other life stages”.

Table 4.2-5 U.S. EPA Ambient Water Quality Criteria For Dissolved Oxygen (EPA 440/586003)

Coldwater Criteria (mg/L) Warmwater Criteria (mg/L) Early Life Stages1,2

Other Life Stages

Early Life Stages2

Other Life Stages

30 Day Mean NA3 6.5 NA 5.5 7 Day Mean 9.5 (6.5) NA 6.0 NA 7 Day Mean Minimum NA 5.0 NA 4.0 1 Day Minimum4,5 8.0 (5.0) 4.0 5.0 3.0 1 These are water column concentrations recommended to achieve the required intergravel dissolved oxygen concentrations shown in parentheses. The 3 mg/L differential is discussed in the criteria document. For species that have early life stages exposed directly to the water column, the figures in parentheses apply. 2 Includes all embryonic and larval stages and all juvenile forms to 30-days following hatching. 3 NA (not applicable). 4 For highly manipulatable discharges, further restrictions apply (see pg. 37 of U.S. EPA 1986b]. 5 All minima should be considered as instantaneous concentrations to be achieved at all time.


“During periodic cycles of dissolved oxygen concentrations, minima lower than acceptable constant exposure levels are tolerable as long as:

1. the average concentration attained meets or exceeds the criterion;

2. the average dissolved oxygen concentration is calculated as recommended in Table 3 [of U.S. EPA 1986b]; and

3. the minima are not unduly stressful and clearly are not lethal.

For controlled discharges, it is recommended that the occurrence of daily minima below the acceptable 7-day mean minimum be limited to 3 weeks per year or that the acceptable one-day minimum be increased to 4.5 mg/L for coldwater fish and 3.5 mg/L for warmwater fish.”

Putah Creek upstream (R1) and downstream (R2) dissolved oxygen levels, based on self-monitoring by plant staff, are summarized in Table 4.2-6.

Table 4.2-6 Dissolved Oxygen (D.O.) Levels in Putah Creek Immediately Upstream (R1) and

Downstream (R2) of the WWTP Effluent Discharge

D.O. at R1 (mg/L) D.O. at R2 (mg/L) Month

Mean Max Min Mean Max Min

Apr 2000 9.4 10.2 8.7 9.3 10.2 8.6

May 2000 9.4 10.0 7.8 9.2 10.1 7.8

Jun 2000 10.5 12.1 9.5 9.8 10.1 8.7

Jul 2000 9.8 13.1 8.6 9.0 13.1 8.6

Aug 2000 8.1 8.8 7.4 7.8 8.5 7.1

Sep 2000 10.0 11.9 6.6 9.5 10.7 7.8

Oct 2000 9.4 12.1 8.3 9.1 10.2 8.4

Nov 2000 11.6 12.6 10.3 10.9 12.2 9.5

Dec 2000 11.4 11.9 10.4 11.0 11.6 10.2

Jan 2001 11.5 12.7 9.8 11.1 12.4 9.7

Feb 2001 12.2 14.7 10.0 11.3 12.9 9.9

Mar 2001 10.6 10.2 8.2 10.2 11.0 9.8

Apr 2001 9.8 10.9 9.0 9.8 10.8 9.1

May 2001 9.6 10.6 7.9 9.4 10.3 7.9

Jun 2001 11.1 13.8 9.0 10.3 11.36 9.2

Jul 2001 7.9 9.5 6.6 8.0 9.3 6.7

Aug 2001 7.5 8.9 6.7 7.5 9.0 6.3

Sep 2001 8.4 10.2 7.6 8.0 9.1 6.8


Table 4.2-6 Dissolved Oxygen (D.O.) Levels in Putah Creek Immediately Upstream (R1) and

Downstream (R2) of the WWTP Effluent Discharge

D.O. at R1 (mg/L) D.O. at R2 (mg/L) Month

Mean Max Min Mean Max Min

Oct 2001 10.3 12.5 8.8 8.6 9.4 8.3

Nov 2001 9.5 10.2 8.9 8.9 10.4 8.1

Dec 2001 9.1 9.8 8.1 8.6 9.3 8.2

Jan 2002 10.2 12.3 8.5 9.7 11.3 7.9

Feb 2002 13.9 16.0 10.8 11.3 13.9 8.9

Mar 2002 9.8 12.8 8.1 10.2 11.6 9.0

Apr 2002 9.0 10.3 8.6 8.7 10.2 7.8

May 2002 8.5 8.9 7.9 8.0 8.6 7.6

Jun 2002 8.3 8.8 7.6 7.5 7.8 7.1

Jul 2002 8.9 9.5 8.4 8.4 9.5 7.1

Jan 2003 10.3 11.2 9.6 10.2 10.6 9.5

Feb 2003 11.4 13.4 9.8 10.7 12.2 9.0

Mar 2003 9.7 11.7 8.3 10.2 11.6 9.0

Apr 2003 10.1 10.8 9.6 9.2 10.0 8.6

May 2003 7.6 9.8 5.7 8.7 9.7 7.8

Jun 2003 6.7 7.1 6.4 7.8 8.4 7.3

Jul 2003 8.9 9.5 8.4 7.3 8.5 6.5

Aug 2003 7.5 7.8 7.3 7.5 7.8 7.3

Sep 2003 7.1 7.8 6.6 8.1 9.0 6.8

Oct 2003 8.3 8.8 7.4 8.9 9.7 8.3

Nov 2003 10.2 12.5 8.4 10.4 13.4 8.8

Dec 2003 10.4 11.3 9.2 10 10.7 9.5

Mar 2004 9.6 10.2 8.6 9.4 11.5 8.3

Min 6.7 7.1 5.7 7.3 7.8 6.3

Max 13.9 16 10.8 11.3 13.9 10.2

Source: Weekly grab data reported in Discharger Self-Monitoring Reports for April – July 2002, January – December 2003, and March 2004.

Based on Table 4.2-6, it is apparent that both R1 and R2 dissolved oxygen levels occasionally fall below the NPDES permit limit of 7.0 mg/L. Nevertheless, the lowest measured R2 dissolved oxygen level of 6.3 mg/L would be protective of the fish community and other aquatic biological resources of Putah Creek, downstream of the WWTP. Moreover, the long-


term mean and median dissolved oxygen concentrations at R2 (immediately downstream of the discharge) are higher than those at R1 (immediately upstream of the discharge).

The final issue pertinent to this assessment is whether the effluent discharged under the project condition would be expected to cause a “dissolved oxygen sag” (i.e., lowest dissolved oxygen resulting from the oxygen demand of a discharge over time) at distances downstream of the point of discharge and the R2 monitoring station. Under extreme conditions, a dissolved oxygen sag can reduce dissolved oxygen below levels necessary to support aquatic life. Using available data, this can best be addressed by determining the effluent BOD and its ammonia concentration – both of which require oxygen from the water column to be assimilated. Of the two, ammonia has the greater demand compared to BOD.

Starting with ammonia, the plant under the project condition will fully nitrify and denitrify, which removes ammonia from the treated effluent discharge. Consequently, ammonia concentrations will be negligible and thus so too will downstream oxygen consumption to assimilate the ammonia. As for effluent BOD levels, based on daily data reported in Discharger Self-Monitoring Reports for April 2000–July 2002, January–December 2003, and March 2004, mean effluent BOD levels tend to be about 1.2-1.4 mg/L, with highs generally below 5 mg/L. These are very low BOD levels for a municipal discharge and are not expected to result in a substantial dissolved oxygen sag downstream. Moderate re-aeration and photosynthetic activity within the channel would be expected to replace the oxygen used to assimilate the BOD discharged.

Discharges under the project condition are not expected to reduce downstream dissolved oxygen levels below the U.S. EPA’s recommended minimum levels summarized in Table 4.2-5. Resident fish and benthic macroinvertebrate communities downstream of the WWTP are warmwater communities. No anadromous salmonid spawning occurs downstream of the WWTP. Consequently, the project is not expected to result in dissolved oxygen related impacts to Putah Creek’s aquatic biological resources.


Impact 4.2-7. Lead. Discharges of treated effluent under the project condition may contain lead. At sufficiently high levels, lead can cause toxicity to aquatic life; hence, this is a constituent of concern regarding impacts to aquatic life in Putah Creek. However, lead concentrations in Putah Creek would not be high enough to affect aquatic resources. This impact is considered less than significant.

During the period of assessment (April 2000 to present), lead was detected in the effluent at a concentration exceeding the CTR’s chronic criterion once, in June 2002, at a concentration of 7.42 µg/L. The remaining 14 sample concentrations were less than 0.5 µg/L, well below the CTR chronic lead criterion of 2.79 µg/L (based on the lowest measured effluent hardness of 110 mg/L). The frequency of exceedance of the applicable lead criterion observed in the data set evaluated is less than the once in 3-year frequency deemed acceptable by U.S. EPA. The sporadic nature and extreme magnitude of the observed maximum value in comparison to all other UC Davis samples and other wastewater treatment facilities supports the interpretation


that the value is not representative of the routine performance of the campus WWTP. Compliance with the applicable hardness-based lead criteria in the receiving water, consistent with U.S. EPA’s guidance, is expected under the project condition.


Impact 4.2-8. pH. The project could alter pH levels of ambient waters downstream of the discharge, but not to an extent that would affect aquatic resources. This impact is considered less than significant.

The NPDES permit for this facility includes an effluent pH limitation of 6.5 to 8.5. pH of water in this range, and even somewhat higher (RWQCB 2002; U.S. EPA 1999) is protective of freshwater aquatic life. The minimum pH recorded for the effluent was 6.5 and the maximum was 8.7 (May 2000). Typical effluent pH ranges between about 7 and 8. The minimum R1 (upstream) creek pH measured was 7.6, with the lowest measured R2 (downstream) pH being 7.8. pH levels in Putah Creek above the effluent’s highest levels of 8.7 would be caused by factors other than the discharge, such as high photosynthetic activity. Nevertheless, pH levels up to about 9.0 are not of concern for the aquatic biology of Putah Creek (U.S. EPA 1999). Based on these findings, the project would not be expected to have adverse pH effects on the aquatic resources of Putah Creek or downstream water bodies.


Impact 4.2-9. Temperature. The project may result in incremental increases to Putah Creek temperatures downstream of the outfall. Temperature levels are not expected to be sufficient to adversely affect sensitive aquatic resources. This impact is considered less than significant.

The current WWTP generally complies with its NPDES permit limitations for temperature (there were 9 exceedances of the delta 5EF water quality objective contained in the RWQCB Basin Plan (refer to Chapter 4.1, Hydrology and Water Quality) in the March 2000-June 2004 period, out of 170 measurements), and the because the proposed WWTP upgrades generally consist of increases to capacity of the existing treatment processes, the expanded plant is expected to have a similar level of compliance. The applicable water quality objective and NPDES permit limitation for temperature (which are the same) is to limit the increase in receiving water temperature to no more than 5EF. This limitation has varying levels of protectiveness to various species of aquatic life, depending upon the creek’s background temperature at any given time of year. Therefore, this impact assessment is based on calculated “with-project” absolute creek temperatures at the R2 monitoring station (downstream of the discharge), and the effects of the R2 seasonal temperature regime on Putah Creek’s aquatic resources.

Temperature Analysis

Mass-balance calculations were made to estimate downstream (R2) creek temperatures under the project condition. WWTP self-monitoring data for effluent and upstream (R1) temperature for the post-upgrade period of record through June 2004 were applied (via the mass-balance equation) to projected future WWTP effluent discharges (3.8 mgd) and Putah


Creek flow rates based on Accord flows at the I-80 Bridge (see “Instream Flow” section in Environmental Setting). The Accord flows vary depending on whether it is a non-drought or drought year, therefore, both instream conditions were evaluated. Exhibits 4.2-5 and 4.2-6 present the calculated downstream (R2) temperatures for the non-drought and drought flow conditions, respectively.

This assessment provides a reasonable worst-case scenario because inputs include minimum Accord flows and maximum project discharge rates. Hence, the typical project condition would be expected to show lesser thermal effects.

Under both non-drought and drought minimum Accord flow conditions, the project-specific increase in creek temperature, resulting from the maximum project discharge of 3.8 mgd (ADWF) vs. the existing 1.7 mgd (ADWF), would be about 2-4EF in the fall and winter months, with lesser temperature increases (typically <1EF) during the spring and summer periods (Exhibits 4.2-5 and 4.2-6). Fall and winter temperatures would typically remain in the mid 50s to mid 60s EF range, with spring temperatures increasing to summer highs of about 78-80EF, which is similar to existing summer high temperatures. Drought year temperatures would be somewhat higher throughout much of the year compared to non-drought year temperatures.

Assessment

Within the lower Putah Creek corridor downstream of the PDD, the coldwater species (i.e., salmonids) including chinook salmon, rainbow trout, and brown trout would be most sensitive to temperature increases and primarily use reaches upstream of the WWTP. Because the resident trout populations exist upstream of the WWTP, they would be thermally unaffected by the project. Only the anadromous species (i.e., fall-run chinook salmon and potentially steelhead) of coldwater fishes migrate past the plant site in the fall (adult immigration of fall-run chinook salmon), winter (immigration of salmon, steelhead and possibly emigration of both species), and spring months (juvenile emigration of fall-run chinook salmon, and possibly steelhead).

As shown in Exhibits 4.2-3 and 4.2-4, the other native non-salmonid fish species that also are less thermally tolerant (e.g., prickly sculpin) also reside strictly upstream of the WWTP and, therefore, would be unaffected thermally by the project.

The resident fish species using the UC Davis reach of the creek, where the plant discharge is located, constitute a “warmwater” fish community. The thermal tolerances of bluegill, green sunfish, largemouth bass, western mosquitofish, inland silverside, bullheads, catfish, thermally tolerant native species (see RWQCB 2003) and other warmwater fish species that reside in this reach of creek are sufficiently high that the expected seasonal temperature regime under the project condition (Exhibit 4.2-5) would be suitable for these fishes, and the warmwater benthic macroinvertebrate community that co-exists with this warmwater fish community. The one native species, Sacramento blackfish, that occurs primarily downstream of the campus is a thermally tolerant species, that also would find the with-project thermal conditions downstream of the WWTP suitable.


EXHIBIT Future Putah Creek Temperature at 3.8 mgd Discharge – Non-drought Condition 4.2-5

44464850525456586062646668707274767880828486


Tem

pera

ture

(ºF

)

2000 - 1.7 mgd 2000 - 3.8 mgd2001 - 1.7 mgd 2001 - 3.8 mgd2002 - 1.7 mgd 2002 - 3.8 mgd2003 - 1.7 mgd 2003 - 3.8 mgd2004 - 1.7 mgd 2004 - 3.8 mgd

Source: Robertson-Bryan, Inc. 2004 2002

NOTE: Calculated temperature at the R2 monitoring station based on measured effluent and R1 temperature, effluent discharge rate of 3.8 mgd, and drought Accord flows in Putah Creek


EXHIBIT

444648505254565860626466687072747678808284


Tem

pera

ture

(ºF

)


Future Putah Creek Temperature at 3.8 mgd Discharge –Drought Condition 4.2-6


NOTE: Calculated temperature at the R2 monitoring station based on measured effluent and R1 temperature, effluent discharge rate of 3.8 mgd, and drought Accord flows in Putah Creek


Based on the above, the aquatic species most sensitive to additional thermal loading from the WWTP under the project are fall-run chinook salmon and steelhead (immigrating adults and emigrating juveniles). Hence, an assessment for these fish species and life stages is provided below.

Neither fall-run chinook salmon nor steelhead migrate past the WWTP discharge, thereby using the downstream reach of creek, between about May (expected end of emigration season for South Fork Putah Creek) and mid-October (initiation of fall-run chinook salmon immigration). Consequently, the project effect on creek temperature downstream of the discharge during the May through mid-October period of the year would have little to no effect on these anadromous salmonid species.

In looking at the remaining months of the year (i.e., mid-October through May), current and projected future creek temperatures under the project condition (Exhibit 4.2-5) would be suitable for both immigration and emigration of fall-run chinook salmon and steelhead during this period. Immigration of adult fall-run chinook salmon into Putah Creek has historically occurred mid-October through December, with spawning occurring concurrently in the initial few miles downstream of the PDD. The Accord’s supplemental flows are targeted at aiding fall-run chinook salmon immigration begin November 15th.

A thermal barrier to fall-run chinook salmon immigration can occur when water temperatures become sufficiently elevated across most or all of the cross-section of the channel. Where low dissolved oxygen levels were not a problem, Dunham (1968) reported that water temperatures approaching 76°F in the lower Klamath River had no observable effect on the upstream migration of adult chinook salmon. Marine (1992) reported that adult chinook salmon can tolerate short-term and transient temperature exposures of 77°F to 80.6°F during spawning migrations. Moyle (1976) noted that adult spring-run chinook salmon in the Sacramento-San Joaquin system tributaries, spent summer months in deep holes of upstream areas where water temperature ranged from 69.8°F to 77EF. Hence, given the sufficient dissolved oxygen concentrations of the Putah Creek, a thermal barrier to adult chinook salmon spawning migrations would not be expected to occur until water temperatures approach or exceed approximately 80°F over most or all of the cross-section of the channel. This would not occur in the creek during October under the project condition (Exhibit 4.2-5), when fall-run chinook salmon immigration begins in this water body.

May temperatures are above those that are favorable for anadromous salmonid emigration under existing conditions, and could be increased somewhat (typically <1°F) under the project condition. Nevertheless, work on other rivers (e.g., American and Yuba Rivers) by the DFG has shown that the vast majority of fall-run chinook salmon emigrate as post-emergent fry during the winter and early spring months. Consequently, the vast majority of fall-run chinook salmon emigration is believed to be completed by the end of April. Likewise, in Putah Creek, the supplemental rearing and outmigration flows stipulated the Accord last each year until April 15 to reflect the anticipated primary emigration period for salmonids.


The incremental increases in Putah Creek temperatures that could occur under the project condition would have a less-than-significant effect on fall-run chinook salmon use of the creek, and would not substantially change the opportunity for steelhead to make opportunistic use of Putah Creek.


Impact 4.2-10. Turbidity. Discharges under the project could cause elevated turbidity levels in the receiving waters at various times during the year because of elevated effluent turbidity or in-channel erosion. However, effluent turbidity levels are generally expected to be lower than Putah Creek levels and not adversely affect sensitive aquatic resources. This impact is considered less than significant.

The NPDES permit for the WWTP includes a year-round effluent turbidity limit of 2 nephelometric turbidity units (NTUs) as a daily average, 5 NTUs as a daily maximum to be achieved 95% of the time, and an instantaneous maximum not to be exceeded of 10 NTUs. These levels are below turbidity levels that would adversely affect the aquatic ecology of Putah Creek (see RWQCB 2002), and are set in the NPDES permit to ensure adequate disinfection for human health protection associated with contact recreation in the receiving waters. Turbidity can adversely reduce sight feeding ability of aquatic organisms. Other than one incident involving a concrete dust spill, the only exceedances of these limits post-plant-upgrade occurred under winter storm event conditions, at which time receiving water turbidity was higher than that of the effluent. WWTP staff have attributed wet-weather turbidity spikes to stormwater discharges from various exterior campus areas including animal facilities. WWTP staff have provided education and guidance to the person using these animal facilities to modify their winter-period operations to reduce the probability of high turbidity discharges to the sewer system. WWTP staff utilized alum as a coagulant aid in 2003-2004 to aid with turbidity control that resulted in elevated aluminum concentrations; however, the use of other organic polymers in conjunction with copper control experiments was found to be effective in reducing turbidity and is now thought to be successful at maintaining compliance with the permit limits. In addition, the additional filtration unit included in the proposed project will provide greater capacity and reliability for control of short-term unexpected turbidity events. During these turbidity spikes, WWTP staff increased the use of chemical coagulants in the wastewater treatment process and investigated potential campus sources of the turbidity. The use of aluminum sulfate as a coagulant was later modified to reduce potential release of elevated aluminum concentrations in the effluent. WWTP staff investigated and performed tests to identify other polymers, and now have identified polymer-based coagulants that can be successfully used to control future turbidity spikes. Consequently, operations of the plant under the proposed project conditions would not produce effluent turbidity levels that would adversely affect aquatic resources in Putah Creek.

The higher rates of discharge that could occur under the project condition (up to an ADWF of 3.8 mgd) would not cause notable additional bank or streambed erosion, relative to existing conditions. The instream flows in Putah Creek (refer to Tables 4.2-1 and 4.2-2) show that the channel is sufficiently large to accommodate flows orders of magnitude higher than that discharged from the WWTP and the project-related increase in discharge, and thus can


accommodate the additional effluent discharge associated with the project without incurring increased instream turbidity because of channel incision or erosion. Moreover, the project does not include any in-channel construction activities, and will incorporate adequate onsite construction Best Management Practices (BMPs) to prevent stormwater-related increases in creek turbidity because of construction activities onsite (as discussed in the project’s Tiered IS).


Impact 4.2-11. Additive or Synergistic Toxicity. There is a potential for WWTP discharges under the project to cause additive or synergistic toxicity to aquatic organisms in Putah Creek. However, the low individual constituent concentrations and infrequent toxicity results suggest that adverse synergistic effects are unlikely. This impact is considered less than significant.

This impact was evaluated in two ways: (1) a review of the scientific literature on additive and synergistic toxicity; and (2) review of the WWTP whole effluent bioassay results. Each is discussed below.

Literature Findings

There are three possible interactions of multiple constituents in receiving waters: (1) additivity; (2) antagonism; and (3) synergism (U.S. EPA 1991a). Additivity occurs when the toxicity of a mixture of constituents is greater than the toxicity of each individual constituent alone, creating an “additive” effect (i.e., 1+1=2). Antagonistic effects occur when the toxicity of a mixture decreases relative to the toxicity of individual constituents (i.e., 1+1=1). Synergistic effects occur when the toxicity of a mixture of constituents is greater than the sum of the individual constituents, such that there is a multiplying effect (i.e., 1+1=3).

The important factors in the assessment of potential interactions between pollutants are: the (1) the concentrations to which aquatic life are exposed; and (2) the exposure duration. While some studies have indicated the existence of interactive effects between toxicants, it is important to note the concentrations used in the bioassays and the time required to produce specific toxicological endpoints in the evaluation of interactive effects. Studies indicate that interactive effects are most prevalent when exposure concentrations are significantly elevated (as compared to concentrations expected downstream of the WWTP) and that such effects decline with decreasing concentrations. Regarding toxicity of multiple constituents, the U.S. EPA has stated that available data indicate that acute toxicity can be additive; however, the data do not support additivity of chronic toxicity (U.S. EPA 1991b).

Acute toxicity of trace metal mixtures has been shown to be higher than the toxicity of the individual metals, when concentrations are significantly elevated, relative to normal ambient concentrations. For example, increased acute toxicity has been observed for mixtures of copper, cadmium, and zinc at concentrations that were at least 50 times greater than the maximum concentrations measured in the Sacramento River (LWA 2002). The toxicity may be additive or synergistic, depending on the organism being tested and the exposure concentrations (e.g., Spehar and Fiandt 1986).


Toxicity tests of mixtures of metals show no effect on survival on longfin dace (Agosia chrysogaster) when concentrations are much greater than those that would occur in the receiving waters under the project condition. For instance, the copper concentration that shows 100% survival when mixed with zinc is 0.1 mg/L (100 µg/L). Likewise, the zinc concentration showing 100% survival when mixed with copper is 0.2 mg/L (200 µg/L). Available literature information indicates that the actual trace metal levels in the receiving waters are not expected to cause additive toxicity.

Regarding pesticides, Macek (1975) found that aquatic midge larvae exposed to a combination of atrazine and other organophosphate insecticides at elevated levels showed greater than additive acute toxicity. Additive and/or synergistic reactions between pesticides have not been fully examined; however, trends seem to show greater than additive toxicity when pesticides are mixed at elevated concentrations (Howells 1994, Macek 1975). The interactive nature of these pesticides at concentrations less than 1 µg/L was not reported. A set of tests performed with diazinon + parathion was found to exhibit additive toxicity. However, the concentrations of diazinon used were quite high, ranging from 100–140 µg/L. By comparison, measured concentrations of diazinon in the Sacramento River near Freeport are typically below detection at a reporting level of 0.05 µg/L, with seasonal levels of diazinon reaching 0.16 µg/L. Therefore, the levels of diazinon that exhibited additive toxicity with parathion were approximately two orders of magnitude greater than levels seen in the Sacramento River.

These studies indicate that interactive effects can occur when concentrations are significantly elevated, and that such effects decline with decreasing concentration. However, they are not expected to occur at the constituent concentrations that typically exist in the undiluted UC Davis WWTP effluent and its receiving waters, downstream of the discharge. A direct evaluation of this is provided by whole effluent toxicity testing (i.e., bioassay testing) conducted by the WWTP. Results from bioassays conducted for this facility post-upgrade are presented and discussed below.

Bioassay Results

The NPDES permit for this and other WWTPs require both acute and chronic toxicity testing (bioassays) for a number of reasons, one of which is to address the issue of additive and synergistic toxicity. Because the whole effluent is tested, and in the chronic tests effluent is diluted at different ratios with receiving water, the potential to cause toxicity in the receiving water, downstream of the discharge, is effectively evaluated.

The WWTP NPDES permit requires this facility to conduct quarterly acute and chronic bioassays to determine whether the effluent (a complex mixture of many constituents) would be expected to cause toxicity to aquatic life upon its discharge into the receiving waters. The acute tests are 96-hr (4-day) survival tests using early life stages of rainbow trout. The chronic tests are U.S. EPA’s 7-day three-species tests using an invertebrate (Ceriodaphnia dubia), a fish (Pimephales promelas) – the fathead minnow; and an algae (Selenastrum capricornutum). These latter bioassays assess survival, growth, and reproduction of these test organisms resulting from


the 7-day exposure duration. The results of both the acute and chronic bioassay testing are examined and interpreted below.

The acute bioassays conducted quarterly from March 2000 through May 2004 showed that the percent survival of rainbow trout exposed to undiluted WWTP effluent was not significantly different from the percent survival of trout exposed to laboratory control water. All results for the 96-hr effluent tests were 100% survival in both the effluent and laboratory control water. These results show that the undiluted effluent is not acutely toxic to a sensitive fish species – the rainbow trout.

A total of 53 chronic bioassays were conducted for the WWTP between April 2000 and April 2004 (16 fish tests, 22 invertebrate tests, and 15 algae tests) (Table 4.2-7). Undiluted WWTP effluent did not reduce fish survival, relative to the laboratory control treatment, in any of the 16 tests. Conversely, undiluted Putah Creek water, taken upstream of the discharge, significantly reduced fish survival in 7 of the 16 tests (44% of the time). On two occasions (July 25, 2003 and April 23, 2004), fish growth was reduced in the undiluted effluent, relative to growth of fish exposed to laboratory control water. However, in both cases, growth rates in the effluent treatment were equivalent to (and in fact just slightly higher than) growth that was observed in fish exposed to undiluted creek water.

Regarding the invertebrate tested, C. dubia, exposure to the undiluted effluent never resulted in reduced survival, relative to survival observed in the laboratory control treatment. As for the reproduction endpoint for this test (i.e., average number of young produced per adult), reproduction was reduced in the effluent exposure on two occasions (June 30, 2001 and October 26, 2001) and on three occasions in the undiluted creek water treatment.

Regarding the algae tested, S. capricornutum, exposure to the undiluted effluent never resulted in a reduction in growth (cells per ml), relative to growth in the laboratory control. The higher nutrient levels and other characteristics of both the effluent and creek water typically resulted in greater growth in both effluent and creek treatments compared to the laboratory water treatment. Growth in the creek water treatment was occasionally higher than that of the effluent, with growth in the effluent treatment typically being intermediate between that observed in the laboratory water and the creek water. In no case did the effluent cause a toxic effect.

The bioassay findings discussed above indicate that the undiluted WWTP effluent does not cause lethality to the sensitive aquatic species evaluated, rarely causes low-level effects such as reduced growth, and is not expected to cause either in Putah Creek or downstream waters. In fact, Putah Creek water was frequently (44% of the time) observed to reduce survival of fathead minnows in the 7-day chronic test, and also had effects on fathead minnow growth and C. dubia reproduction more often than did the effluent. These results indicate that the addition of WWTP effluent to Putah Creek actually decreases the potential for toxicity to aquatic species residing within the creek. The bioassay results for this facility are consistent with the findings from the scientific literature evaluation discussed above regarding additive and synergistic toxicity. Discharges from the WWTP under the project condition are not expected to cause


receiving water toxicity, regardless of dilution ratio. Any additive or synergistic toxicity that may occur is occurring at insignificant levels.


Table 4.2-7 Chronic Three-Species Toxicity Test Results for the WWTP effluent from

Quarterly Testing During the Period April 2000 through April 2004. Fish (Fathead Minnow) Survival and Growth Invertebrate (C. dubia) Survival and Growth Algae Growth

(S. capricornutum) Date

Survival Growth Survival Reproduction Growth Apr 27, 2000 Not reported Not reported No Effect No Effect Not Reported May 26, 2000 Not reported Not reported No Effect No Effect Not Reported Jun 23, 2000 No Effect

(Reduced in RW)

No Effect No Effect No Effect No Effect (Effl. growth between that of LC and RW)

Jul 31, 2000 Not reported Not reported No Effect No Effect Not Reported Aug 18, 2000 Not reported Not reported No Effect No Effect Not Reported Sep 22, 2000 No Effect

(Slight reduction at 50% and 25% dilutions)

No Effect (No effect at 50% and 25% dilutions)

Not Reported Not Reported Not Reported

Nov 29, 2000 Not reported Not reported No Effect No Effect Not Reported Dec 22, 2000 No Effect

(Reduced in RW)

No Effect (Reduced in RW)

No Effect No Effect (Reduced in RW)

No Effect (Effl. growth equivalent to RW)

Jan 30, 2001 Not reported Not reported No Effect Reduced in Effl. Not Reported Apr 3, 2001 No Effect

(Reduced in RW)

No Effect No Effect No Effect (Reduced in RW)

No Effect (Effl. growth between that of LC and RW)

Jun 22, 2001 No Effect No Effect No Effect No Effect No Effect (Effl. and RW equivalent)

Oct 26, 2001 Not reported Not reported No Effect Reduced in Effl. Not Reported Dec 21, 2001 No Effect

(Reduced in RW)


No Effect No Effect No Effect (Effl. growth between that of LC and RW)

Feb 27, 2002 No Effect No Effect No Effect No Effect No Effect (Effl. growth between that of LC and RW)

Jul 1, 2002 No Effect (Reduced in

Effl. growth slightly reduced

No Effect No Effect No Effect


Table 4.2-7 Chronic Three-Species Toxicity Test Results for the WWTP effluent from

Quarterly Testing During the Period April 2000 through April 2004. Fish (Fathead Minnow) Survival and Growth Invertebrate (C. dubia) Survival and Growth Algae Growth

(S. capricornutum) Date

Survival Growth Survival Reproduction Growth RW) from LC, but

substantially higher than RW

Aug 28, 2002 No Effect No Effect


Oct 28, 2002 No Effect No Effect

No Effect No Effect No Effect (Effl. growth between that of LC and RW)

Jan 28, 2003 No Effect No Effect No Effect No Effect No effect (RW growth higher than Effl. and LC)

Apr 25, 2003 No Effect (Reduced in RW)



Jul 25, 2003 No Effect Effl. growth slightly reduced relative to LC, but equivalent to (slightly higher than) RW


Oct 29, 2003 No Effect (Reduced in RW)

No Effect No Effect No Effect (Reduced in RW)

No Effect

Jan 22, 2004 No Effect No Effect No Effect No Effect No Effect Apr 23, 2004 No Effect Effl. growth

slightly reduced relative to LC, but equivalent to (slightly higher than) RW


Notes: No effect indicates that the survival, growth, or reproduction was not significantly reduced in undiluted effluent relative to the laboratory control. Effl. = undiluted effluent RW = Putah Creek water upstream of discharge LC = laboratory control water.


Impact 4.2-12. Instream Flows. The project would facilitate increasing the ADWF discharges from the WWTP from the existing 1.7 mgd flow (current maximum permitted ADWF design capacity of 2.7 mgd) to an ADWF design capacity of 3.8 mgd. Although changes in instream flow can affect habitat conditions or water quality characteristics such as turbidity, incremental changes would be small and would not adversely affect sensitive aquatic resources. This impact is considered less than significant.

Discharges under the project would increase slowly over time, from the current ADWF of 1.7 mgd to the projected ADWF of 3.8 mgd in about 2013, based on current projections. Changes in streamflow can directly affect aquatic resources through the depth, area, velocity, or duration of instream habitat inundation. Streamflow can also indirectly affect other physical and water quality conditions within streams such as turbidity levels, sedimentation patterns, or sediment substrate characteristics such as the mixture of fine and coarse sediment deposition. This proposed project, with its minor incremental increases in effluent discharge would not be expected to result in changes in downstream dry weather flows to a degree that would adversely impact the creek’s aquatic resources. In fact, a 2.1 mgd or less change in flow in the Putah Creek channel would be difficult to discern via observations, and would likely only be notable via accurate discharge measurements.

Precipitation season flows within the creek, particularly peak flows, are driven primarily by storm events, not the permitted capacity of the WWTP. Consequently, peak flows during the winter months will change little in Putah Creek, downstream of the WWTP with the proposed project.

The hydrologic (flow) changes that would occur because of the project would be minor in magnitude, relative to the creeks current seasonal flow regime, and thus would not alter the downstream drainage pattern relative to existing conditions. The minor hydrologic changes that would occur under the project would have less-than-significant effects on the creeks fish communities and other aquatic biological resources.


Impact 4.2-13. Putah Creek Riparian Habitat. The project would not result in flow or water quality conditions that would adversely affect riparian habitat along Putah Creek, downstream of the discharge. In fact, the WWTP discharges help support the riparian vegetative communities downstream of the WWTP during drought-year conditions. The increase in discharge volume facilitated by the project would not adversely affect the riparian community. This impact is considered less than significant.

The gradual increase in effluent discharge to Putah Creek would not adversely impact the creek’s riparian vegetation. As noted above, the additional flow to Putah Creek water levels would be difficult to discern through observations given the large capacity of the channel. Riparian vegetation exists and functions in close association with the location of the flowing channel. The minor incremental effect of the discharge would not measurably affect the channel location or water levels and, thus, is not expected to change riparian vegetation growth patterns. Because riparian vegetation also relies on streamflow for the plants metabolic


needs for water, the incremental additional flows may enhance the viability of riparian vegetation during times of drought when upstream background flows may be reduced. However, this is a minor effect as the frequency of drought flows is relatively low relative to the overall hydrology of the watershed and instream flow requirements of the Accord.


Impact 4.2-14. Eutrophication. The project would add nitrogen and phosphorus to Putah Creek, which could result in additional plant and algal growth. The effects of algal growth can be nuisance or beneficial depending on the timing, duration, and magnitude, however, the incremental project-related changes in nutrient concentrations are not expected to cause problematic eutrophic conditions. This impact is considered less than significant.

Putah Creek currently receives an ADWF of 1.7 mgd from the WWTP. The effluent discharged from this facility contains nutrients (i.e., nitrogen and phosphorus) that contribute to the nutrient levels of downstream waters. Neither nitrogen nor phosphorus is likely to limit plant and algal growth in the creek because concentrations are relatively high compared to the minor amounts that are necessary to stimulate algal growth in streams, downstream of the plant, under existing conditions (refer to Section 4.1, Hydrology and Water Quality and also see Table 4.2-7, algae results). Factors other than nutrient levels, such as turbidity, riparian shading and associated light limitation, temperature, substrate, flow velocities, etc. are more likely to work collectively, along with nutrient levels, to dictate the level of plant and algal growth that occurs in Putah Creek. Currently, problem-level eutrophication does not occur throughout Putah Creek, downstream of the WWTP and, based on the numerous factors determining the trophic condition of the creek, problem eutrophic conditions are not expected to occur under the project condition.

The WWTP’s NPDES permit includes a requirement for quarterly monitoring of effluent phosphorus levels and more frequent monitoring of nitrogen compounds (i.e., ammonia, nitrate and nitrite). The SWRQCB is expected to develop and adopt nutrient objectives for surface waters in the future. Upon adoption of such objectives, future revised NPDES permits for this facility will include appropriate effluent limitations to ensure compliance with the adopted nutrient standards. In addition, if problem eutrophication were to develop downstream of the plant before adoption of such nutrient objectives, the NPDES permit could still be revised to address the issue to appropriately protect receiving water beneficial uses.


Impact 4.2-15. Interference with Fish Migration. The project would not interfere with the movements of resident or migratory fishes past the point of effluent discharge. This impact is considered less than significant.

This finding is consistent with that of Impact 4.4-9 of the 2003 LRDP EIR that was considered less that significant, which is incorporated herein by reference. Additional discussion supporting this impact determination for fishes using Putah Creek is provided under the other


impact assessments within this chapter, none of which indicate that a thermal, flow, chemical, or other barrier to fish migration would be created by the project.


Impact 4.2-16. Endocrine Disrupting Compounds. Discharges of WWTP effluent under the proposed project could contain endocrine disrupting compounds (EDCs). However, there are no applicable regulatory criteria for these compounds, and it may be many years before the scientific understanding of their effects is sufficient that the RWQCB establishes permit limits for treated wastewater discharges. Impacts to aquatic resources in Putah Creek are not known.

In recent years there has been heightened scientific awareness and public debate over potential impacts that may result from exposure to endocrine disrupting chemicals (EDCs). Section 4.1, Hydrology and Water Quality, includes a brief review of available literature information regarding the current understanding of the sources and environmental effects of EDCs in aquatic ecosystems. The World Health Organization (WHO) defines an EDC as a substance or mixture that alters function of the endocrine system and consequently causes adverse health effects in an intact organism or its progeny (World Health Organization 2002). Endocrine disruption may be described as a functional change that may lead to adverse effects, not necessarily a toxicological end-point. Most EDCs are human-made synthetic chemicals released into the environment unintentionally; some EDCs are natural to the environment such as compounds produced in soybeans and garlic. Although there are some known EDCs, many chemicals are termed “suspect,” because there are not enough data to make a conclusive determination of their endocrine disrupting characteristics.

The ecological effects of EDCs in the aquatic environment were first reported in the 1990s including studies that suggested that the presence of natural and synthetic estrogen hormones in wastewater induced vitellogenin production in male fish which is a protein involved in reproduction normally and normally only found in females (Desbrow et al. 1998). Similar results were observed with alkylphenolic compounds which are breakdown products of industrial surfactants used in products such as paints, herbicides, and cosmetics (Jobling et al. 1996). Other research has since confirmed that natural and synthetic estrogens are present in effluents in sufficient quantity to cause endocrine disruption in fish (Rodgers-Gray et al. 2000). Observed endocrine disruption effects include imposex of molluscs by organotin compounds; developmental abnormalities, demasculisation and feminisation of alligators in Florida by organochlorines; feminisation of fish by waste water effluent from sewage treatment plants and paper mills; hermaphrodism in frogs from pesticides (World Health Organization 2002, Lintelmann et al. 2003); and adverse effects in mosquitofish (Batty and Lim 1999).

Some compounds known to cause EDC-type effects are regulated via ambient water quality criteria or drinking water standards based on their toxicological and carcinogenic effects. However, there no applicable water quality criteria for natural and synthetic estrogens or related pharmaceutical chemicals.


Because there are no current regulatory criteria with which to evaluate effluent concentrations of EDCs and the research-based literature studies that indicate the subject is scientific understanding of EDC effects in the environment is still emerging, the potential impact to aquatic resource in Putah Creek and significance of the effect cannot be evaluated. Because this issue is not well understood and is the subject of ongoing research, a conclusion on significance of the environmental impact cannot be reasonably reached. Section 15145 of the State CEQA Guidelines provides that, if after a thorough investigation a lead agency finds that a particular impact is too speculative for evaluation, the agency should note its conclusion and terminate discussion of the impacts. This is the case here. No impact conclusion can be made based on research of this issue. However, UC Davis will monitor ongoing research and will consult with the RWQCB on further permitting actions, if needed.

▪ Mitigation: No mitigation is required because the impact was not determined to be significant.


Terrestrial Biology

The cumulative setting for the WWTP expansion project is the proposed WWTP expansion to provide adequate capacity for planned growth through 2013, the anticipated additional modular expansion of the WWTP to meet campus demands for wastewater treatment under the 2003 LRDP, LRDP buildout (2015-16), and other cumulative projects. The 2003 LRDP EIR fully analyzed cumulative terrestrial biological impacts for this project because it addressed the impacts of the complete WWTP expansion, the 2003 LRDP buildout, and other related projects that could have related effects.

The project would result in a less-than-significant contribution to cumulative impacts to special-status species. The WWTP expansion would not affect special-status plants because of the existing disturbed condition of the project area. Further, the project would have a less-than-significant effect on western pond turtle because the project area contains low-quality habitat for this species, there are no basking sites, and areas immediately adjacent to the project area do not support suitable breeding habitat for this species.

Impact 4.2-17. Terrestrial Biology. The proposed project could contribute to the cumulative loss in the region of wetland and riparian habitat for resident and migratory wildlife species and special status plants. However, the proposed project would not contribute to the impact because the 2003 LRDP EIR Mitigation Measure 4.4-8(c) would compensate for potential wetland habitat loss. Therefore, the impact of the proposed project would be less than significant.

The LRDP EIR determined that development included in the 2003 LRDP could contribute to the significant and unavoidable cumulative loss of wetland and riparian habitat for resident and migratory wildlife species and special status plants (LRDP Impact 4.4-13). The LRDP EIR found the potential cumulative impact significant and unavoidable because the habitat loss could be associated with the actions of other entities and UC Davis cannot guarantee implementation of mitigating actions of the other entities, including implementation of the


Yolo County NCCP and Solano County HCP. The proposed project could result in wetland and riparian habitat loss subject to the LDRP Impact 4.4-13 should the 0.8 acre emergency wastewater storage basin be determined to be a habitat of concern by DFG or the RWQCB. However, implementation of the 2003 LRDP Mitigation Measure 4.4-8(c) (described above for Impact 4.2-2) would result in UC Davis fully compensating for the loss from the project of the habitat and, therefore, the project would not contribute to the cumulative impact of habitat loss.

Aquatic Resources

The project constitutes the first phase of expansion of the WWTP, which is expected to provide adequate capacity for planned growth through about 2013 and an ADWF design capacity of 3.8 mgd. The campus anticipates that additional modular expansion of the WWTP will be required beyond the improvements addressed in the proposed project to meet campus demands for wastewater treatment projected under the 2003 LRDP. A future expansion would result in facilities with an anticipated ADWF design capacity of 4.3 mgd, meeting planned growth through 2017.

The 2003 LRDP EIR (Impact 4.4-15, pp. 4.4-46 and 4.4-47) concluded that development of the 2003 LRDP, including the planned WWTP expansion, would not contribute to a cumulative adverse impact on aquatic biological resources, including special status fish species. This cumulative impact determination, and its discussion, is incorporated by reference. Based on the referenced information and the additional information provided in this chapter, that the cumulative condition of the aquatic biological resources of Putah Creek would not be significant (i.e., would not be adversely impacted). This conclusion is based on the following facts and measures that are currently being implemented, and will be implemented in the future, to preserve and enhance the integrity of the creek’s aquatic ecology.

< Accord flows – The Putah Creek Accord effectively increases the probability of the presence of flow in the lower Putah Creek channel compared to conditions that existed before the passage of the Accord in early 2000. This is particularly true for drought year conditions where the Accord requires active flow to be maintained in the channel to the I-80 bridge. Before the Accord, long reaches of lower Putah Creek could go dry during summer months. The Accord, in combination with flow produced as a result of the WWTP effluent discharge, provides increased available aquatic habitat during critical drought seasons.

< Tertiary treated discharge from the upgraded WWTP is of far better quality than discharge from the old WWTP that was decommissioned in 2000. The WWTP effluent quality is high and will remain equivalent to existing quality or will improve in the future. Post-2000 effluent and creek bioassay data indicate that effluent discharges tend to decrease (not increase) the potential for aquatic life toxicity in the creek.

< The campus is the only permitted discharger to Putah Creek. Other campus facilities that discharge water to Putah Creek upstream of the WWTP (i.e., Center for Aquatic Biology and Aquaculture, Aquatic Weed Laboratory) are not expected to change their existing discharge operations because they are associated with research-related activities.


Cumulative increases in urban stormwater runoff associated with long-term growth in campus development was addressed in the LRDP EIR. Urban development would primarily increase winter period discharges under high flow conditions. The campus stormwater discharges are regulated by the RWQCB under Phase 2 NPDES municipal stormwater permits, and a variety of individual industrial facilities are regulated under NPDES general industrial stormwater permits. These permits all involve the implementation of best management practices for the avoidance and control of waste discharges to stormwater. Because the stormwater discharges are effectively regulated and because the UC Davis WWTP discharge is of high quality, there would not be any project-related adverse water quality changes that could potentially combine with other discharges to result in cumulative and significant adverse impacts to aquatic biological resources.

< Lower Putah Creek Coordinating Committee has funded fish and wildlife monitoring and habitat improvement projects and for the Putah Creek Streamkeeper to monitor the creek, to acquire grant funds, and to oversee monitoring and habitat improvement projects. As a result, habitat conditions in Putah Creek for both resident and migratory native fish are improving.

The expansion of this facility associated with the future cumulative conditions would result in impacts to aquatic biological resources similar to those identified for the project. Graphical results of an additional thermal mass-balance assessment for the future cumulative condition (4.3 mgd ADWF) are provided in Exhibits 4.2-7 and 4.2-8. The incremental increases in Putah Creek temperatures that could occur under the future cumulative condition would have no effect on the creek’s native fishes residing above the WWTP outfall and salmonid spawning and rearing within the creek upstream of the outfall, and would result in a less-than-significant effect on native and introduced warmwater resident fishes and benthic macroinvertebrates residing downstream of the WWTP, fall-run chinook salmon use of the creek below the outfall as a migratory corridor, and the ability for steelhead to make opportunistic use of Putah Creek.


EXHIBIT Future Putah Creek Temperature at 4.3 mgd Discharge – Non-drought Condition 4.2-7


44464850525456586062646668707274767880828486


Tem

pera

ture

(ºF

)


NOTE: Calculated temperature at the R2 monitoring station based on measured effluent and R1 temperature, effluent discharge rate of 4.3 mgd, and non-drought Accord flows in Putah Creek


EXHIBIT

444648505254565860626466687072747678808284


Tem

pera

ture

(ºF

)

2000 - 1.7 mgd 2000 - 4.3 mgd

2001 - 1.7 mgd 2001 - 4.3 mgd

2002 - 1.7 mgd 2002 - 4.3 mgd

2003 - 1.7 mgd 2003 - 4.3 mgd

2004 - 1.7 mgd 2004 - 4.3 mgd

Future Putah Creek Temperature at 4.3 mgd Discharge – Drought Condition 4.2-8


NOTE: Calculated temperature at the R2 monitoring station based on measured effluent and R1 temperature, effluent discharge rate of 4.3 mgd, and drought Accord Accord flows in Putah Creek

Campus WWTP Expansion Draft EIR EDAW University of California, Davis 4.3-1 Air Quality

4.3 AIR QUALITY

4.3.1 INTRODUCTION

This section addresses the potential effects of the proposed project on air quality, focusing on evaluating the criteria pollutant effects associated with operation of the expanded WWTP and the project’s contribution to cumulative impacts related to criteria pollutants. All other air quality impacts are adequately addressed in the Tiered IS (Appendix A) prepared for this project. All relevant information, including applicable environmental and regulatory settings, standards of significance, and mitigation measures identified in Section 4.3 of the 2003 LRDP EIR, is incorporated by reference and summarized below as appropriate.


Air quality on campus on any given day is influenced by both meterological conditions and pollutant emissions. In general, meteorological conditions vary more than pollutant emissions from day to day, and therefore, tend to have a greater influence on changes in measured ambient pollutant concentrations. A description of climatic and meteorological conditions that affect the campus and general background information regarding air pollutants, sources and characteristics, and ambient air standards are presented in Section 4.3.1 of the 2003 LRDP DEIR. Information from that discussion is incorporated by reference.

4.3.2.1 EXISTING AMBIENT AIR QUALITY

The California Air Resources Board (ARB) and the U.S. Environmental Protection Agency (EPA) currently focus on the following air pollutants as indicators of ambient air quality: O3, CO, nitrogen dioxide (NO2), sulfur dioxide (SO2), particulate matter (PM), and lead. Because these are the most prevalent air pollutants known to be deleterious to human health and extensive health-effects criteria documents are available, they are commonly referred to as “criteria air pollutants.”

The EPA has established primary and secondary national ambient air quality standards (NAAQS) for the following criteria air pollutants: O3, CO, NO2, SO2, respirable particulate matter (PM10), fine particulate matter (PM2.5), and lead. The primary standards protect the public health and the secondary standards protect public welfare. In addition to the NAAQS, the ARB has established California ambient air quality standards (CAAQS) for the criteria air pollutants, sulfates, hydrogen sulfide, vinyl chloride, and visibility-reducing particulate matter. In most cases, the CAAQS are more stringent than the NAAQS. The NAAQS and CAAQ standards are listed in Table 4.3-1.

Criteria air pollutant concentrations are measured at several monitoring stations in the Sacramento Valley Air Basin (SVAB). The Davis-UCD Campus monitoring station and the Woodland-Gibson Road monitoring stations are the closest to the project site with recent data for O3, CO, NO2, PM10, and PM2.5. In general, the ambient air quality measurements from this station are representative of the air quality in the vicinity of the project site. Table 4.3-2 summarizes the air quality data from the most recent 3 years. Ambient air quality conditions with respect to each separate criteria pollutant are described below.

EDAW Campus WWTP Expansion Draft EIR Air Quality 4.3-2 University of California, Davis

Table 4.3-1 California and National Ambient Air Quality Standards and Designations

California (CAAQS) National (NAAQS) 2

Pollutant Averaging

Time Standards 1, 3 Attainment

Status 8

in SVAB Primary 3,4 Secondary 3,5

Attainment Status 9

in SVAB

1-hour 0.09 ppm (180 μg/m3)

N (Serious)

0.12 ppm (235 μg/m3)6

N (Severe)

Ozone (O3) 8-hour – – 0.08 ppm

(157 μg/m3)6

Same as primary standard N

(Recommended)

1-hour 20 ppm (23 mg/m3)

35 ppm (40 mg/m3) Carbon

monoxide (CO) 8-hour 9 ppm

(10 mg/m3)

A 9 ppm

(10 mg/m3)

– U/A

Annual arithmetic

mean – -

0.053 ppm (100 μg/m3) U/A Nitrogen

dioxide (NO2) 1-hour 0.25 ppm

(470 μg/m3) A –

Same as primary standard

–

Annual arithmetic

mean – -

0.030 ppm (80 μg/m3) –

24-hour 0.04 ppm (105 μg/m3) A 0.14 ppm

(365 μg/m3) –

3-hour – - – 0.5 ppm (1,300 μg/m3)

A Sulfur dioxide (SO2)

1-hour 0.25 ppm (655 μg/m3) A – – –

Annual arithmetic

mean 20 μg/m3 * 50 μg/m3 6

Respirable particulate matter (PM10) 24-hour 50 μg/m3

N

150 μg/m3 6


N

Annual arithmetic

mean 12 μg/m3*

N (Proposed) 15 μg/m3

Fine particulate matter (PM2.5) 24-hour - - 65 μg/m3


U (Recommended)

30-day Average 1.5 μg/m3 A – – –

Lead 7 Calendar quarter – - 1.5 μg/m3


A

Sulfates 24-hour 25 μg/m3 A Hydrogen sulfide

1-hour 0.03 ppm (42 μg/m3)

U No federal standards

Vinyl chloride7 24-hour 0.01 ppm

(26 μg/m3) U/A

Visibility-reducing particle

8-hour Extinction coefficient of 0.23 per kilometer —visibility of 10

U


Table 4.3-1 California and National Ambient Air Quality Standards and Designations

California (CAAQS) National (NAAQS) 2

Pollutant Averaging

Time Standards 1, 3 Attainment

Status 8

in SVAB Primary 3,4 Secondary 3,5

Attainment Status 9

in SVAB

matter miles or more (0.07—30 miles or more for Lake Tahoe) because of particles when the relative humidity is less than 70%.

* On June 20, 2002, ARB approved staff recommendation to revise the PM10 annual average standard to 20 μg/m3 and to establish an annual average standard for PM2.5 of 12 μg/m3. These standards took effect on July 5, 2003. Information regarding these revisions can be found at http://www.arb.ca.gov/research/aaqs/std-rs.htm.

1 California standards for ozone, carbon monoxide (except Lake Tahoe), sulfur dioxide (1- and 24-hour), nitrogen dioxide, particulate matter (PM10 and PM2.5), and visibility-reducing particles are values that are not to be exceeded. All others are not to be equaled or exceeded. California ambient air quality standards are listed in the Table of Standards in Section 70200 of Title 17 of the California Code of Regulations.

2 National standards (other than ozone, particulate matter, and those based on annual averages or annual arithmetic means) are not to be exceeded more than once a year. The ozone standard is attained when the fourth highest 8-hour concentration in a year, averaged over 3 years, is equal to or less than the standard. The PM10 24-hour standard is attained when 99% of the daily concentrations, averaged over 3 years, are equal to or less than the standard. The PM2.5 24-hour standard is attained when 98% of the daily concentrations, averaged over 3 years, are equal to or less than the standard. Contact the EPA for further clarification and current federal policies.

3 Concentration expressed first in units in which it was promulgated. Equivalent units given in parentheses are based upon a reference temperature of 25EC and a reference pressure of 760 torr. Most measurements of air quality are to be corrected to a reference temperature of 25EC and a reference pressure of 760 torr; ppm in this table refers to ppm by volume, or micromoles of pollutant per mole of gas.

4 National Primary Standards: The levels of air quality necessary, with an adequate margin of safety, to protect the public health. 5 National Secondary Standards: The levels of air quality necessary to protect the public welfare from any known or anticipated adverse

effects of a pollutant. 6 New federal 8-hour ozone and fine particulate matter standards were promulgated by the EPA on July 18, 1997. Contact the EPA for

further clarification and current federal policies. 7 ARB has identified lead and vinyl chloride as toxic air contaminants with no threshold of exposure for adverse health effects

determined. These actions allow for the implementation of control measures at levels below the ambient concentrations specified for these pollutants.

8 Unclassified (U): a pollutant is designated unclassified if the data are incomplete and do not support a designation of attainment or nonattainment.

Attainment (A): a pollutant is designated attainment if the state standard for that pollutant was not violated at any site in the area during a 3-year period.

Nonattainment (N): a pollutant is designated nonattainment if there was a least one violation of a state standard for that pollutant in the area.

Nonattainment/Transitional (NT): is a subcategory of the nonattainment designation. An area is designated nonattainment/transitional to signify that the area is close to attaining the standard for that pollutant.

9 Nonattainment (N): any area that does not meet (or that contributes to ambient air quality in a nearby area that does not meet) the national primary or secondary ambient air quality standard for the pollutant. Attainment (A): any area that meets the national primary or secondary ambient air quality standard for the pollutant.

Unclassifiable (U): any area that cannot be classified on the basis of available information as meeting or not meeting the national primary or secondary ambient air quality standard for the pollutant.

Sources: California Air Resources Board 2003, 2004


Table 4.3-2 Summary of Annual Ambient Air Quality Data (2001–2003) 3

2001 2002 2003 OZONE (O3) DAVIS-UCD CAMPUS MONITORING STATION State standard (1-hr avg, 0.09 ppm) National standard (1-hr/8-hr avg, 0.12/0.08 ppm)

Maximum concentration (1-hr./8-hr avg., ppm) 0.100/ 0.093

0.121/ 0.088

0.098/ 0.082

Number of days state standard exceeded 0 0 0 Number of days national 1-hr/8-hr standard exceeded 5/2 3/2 2/0 CARBON MONOXIDE (CO) DAVIS-UCD CAMPUS MONITORING STATION State standard (1-hr/8-hr avg, 20/9.1 ppm) National standard (1-hr/8-hr avg, 35/9.5 ppm)

Maximum concentration (1-hr/8-hr avg, ppm) 19.1/3.35 1.9/1.44 3.3/0.83 Number of days state standard exceeded 0 0 0 Number of days national 1-hr/8-hr standard exceeded 0/0 0/0 0/0 NITROGEN DIOXIDE (NO2) DAVIS-UCD CAMPUS MONITORING STATION State standard (1-hr avg, 0.25 ppm) National standard (annual, 0.053 ppm)

Maximum concentration (1-hr avg, ppm) 0.172 0.059 0.060 Number of days state standard exceeded 0 0 0 Annual average (ppm) 0.010 0.012 0.011 RESPIRABLE PARTICULATE MATTER (PM10) WOODLAND-GIBSON ROAD MONITORING STATION State standard (24-hr avg, 50 μg/m3) National standard (24-hr avg, 150 μg/m3) Maximum concentration (μg/m3) 67 82 55 Number of days state standard exceeded (measured/calculated1) 3/19.1 6/36.8 2/- Number of days national standard exceeded (measured/calculated1) 0/0 0/0 0/0 FINE PARTICULATE MATTER (PM2.5) WOODLAND-GIBSON ROAD MONITORING STATION No separate state standard National standard (24-hr avg, 65 μg/m3) Maximum concentration (μg/m3) 57 69 31 Number of days national standard exceeded (measured 2) 0 1 0 Notes: - = not available 1 Measured days are those days that an actual measurement was greater than the level of the state daily standard or the

national daily standard. Measurements are typically collected every 6 days. Calculated days are the estimated number of days that a measurement would have been greater than the level of the standard had measurements been collected every day. The number of days above the standard is not necessarily the number of violations of the standard for the year.

2 The number of days a measurement was greater than the level of the national daily standard. Measurements are collected every day, every 3 days, or every 6 days, depending on the time of year and the site’s monitoring schedule. The number of days above the standards is not directly related to the number of violations of the standard for the year.

3 Measurements from the Davis–UCD Campus and Woodland–Gibson Road monitoring stations.

Sources: California Air Resources Board 2004, EPA 2004


Both ARB and the EPA use monitoring data to designate areas according to their attainment status for criteria air pollutants. The purpose of the designations is to identify those areas with air quality problems and thereby initiate planning efforts for improvement. The three basic designation categories are nonattainment, attainment, and unclassified. The unclassified category is used in an area that cannot be classified on the basis of available information as meeting or not meeting the standards. In addition, the California designations include a subcategory of the nonattainment designation called nonattainment-transitional. The nonattainment-transitional designation is given to nonattainment areas that are progressing and nearing attainment. Attainment designations for the SVAB are shown above in Table 4.3-1 for each criteria air pollutant.

With respect to emission trends and forecasts for the SVAB, the emission levels for the ozone precursors ROG and NOX have been trending downward from 1980. CO emissions have also been trending downward since 1975. On-road motor vehicles are the largest contributors to CO, ROG, and NOX emissions in the SVAB. The implementation of stricter mobile source (both on-road and other) emission standards will continue to decrease vehicle emissions. Control on stationary source solvent evaporation and fugitive emissions will also continue to impact ROG emissions. However, PM10 emissions are trending upward from 1995.

4.3.2.2 SENSITIVE RECEPTORS

The WWTP is located on the south campus, over one mile from sensitive receptors such as daycare centers located on the central campus.


The WWTP currently operates under a Permit to Operate issued by the YSAQMD. The primary source of air emissions from the campus WWTP is the release of Volatile Organic Compounds (VOCs) from treatment processes (particularly from processes in the oxidation ditch). The plant also has an emergency generator, which is a source of air pollutant emissions and is covered under a separate Yolo-Solano Air Quality Management District (YSAQMD) permit. No changes to the existing emergency generator are anticipated with implementation of the proposed project.

Air quality in the project area is regulated by federal, state, and local agencies, including U.S. Environmental Protection Agency (EPA), California Air Resources Board (ARB), and the YSAQMD. Each of these agencies develops rules, regulations, goals and/or policies to attain the goals or directives imposed upon them through legislation. Although federal regulations may not be superseded, both state and local regulations may be more stringent.

Air pollutants subject to federal ambient standards are referred to as “criteria” pollutants because the U.S. EPA publishes criteria documents to justify the choice of standards. One of the most important reasons for air quality standards is the protection of those members of the population who are most sensitive to the adverse health effects of air pollution, termed “sensitive receptors.” The term refers to specific population groups, as well as the land uses, where they would reside


for long periods. Commonly identified sensitive population groups include children, the elderly, and the acutely or chronically ill. Commonly identified sensitive land uses include residences, schools, playgrounds, childcare centers, retirement homes, and hospitals. The federal and state standards for the criteria pollutants are identified in Table 4.3-2.

U.S. Environmental Protection Agency

At the federal level, the EPA has been charged with implementing national air quality programs. The EPA’s air quality mandates are drawn primarily from the federal Clean Air Act (FCAA), which was enacted in 1963. The FCAA was amended in 1970, 1977, and 1990.

The FCAA required the EPA to establish primary and secondary NAAQS, as previously discussed (Table 4.3-1). The FCAA also required each state to prepare an air quality control plan referred to as a State Implementation Plan (SIP). The federal Clean Air Act Amendments of 1990 (FCAAA) added requirements for states with nonattainment areas to revise their SIPs to incorporate additional control measures to reduce air pollution. The SIP is periodically modified to reflect the latest emissions inventories, planning documents, and rules and regulations of the air basins as reported by their jurisdictional agencies. The EPA has responsibility to review all state SIPs to determine conformity with the mandates of the FCAAA and determine if implementation will achieve air quality goals. If the EPA determines a SIP to be inadequate, a Federal Implementation Plan (FIP) may be prepared for the nonattainment area that imposes additional control measures. Failure to submit an approvable SIP or to implement the plan within the mandated timeframe may result in sanctions being applied to transportation funding and stationary air pollution sources in the air basin.

California Air Resources Board

The ARB is the agency responsible for coordination and oversight of state and local air pollution control programs in California and for implementing the California Clean Air Act (CCAA), which was adopted in 1988. The CCAA requires that all air districts in the state endeavor to achieve and maintain the CAAQS by the earliest practical date. The act specifies that districts should focus particular attention on reducing the emissions from transportation and area-wide emission sources, and provides districts with the authority to regulate indirect sources.

The ARB is primarily responsible for developing and implementing air pollution control plans to achieve and maintain the NAAQS. However, local air districts are still relied upon to provide additional strategies for sources under their jurisdiction. The ARB combines this data and submits the completed SIP to the EPA.

Other ARB duties include monitoring air quality (in conjunction with air monitoring networks maintained by air pollution control and air quality management districts), establishing CAAQS (which in many cases are more stringent than the NAAQS), determining and updating area designations and maps, and setting emissions standards for new mobile sources, consumer products, small utility engines, and off-road vehicles.


Yolo-Solano Air Quality Management District

The YSAQMD attains and maintains air quality conditions in the project area through a comprehensive program of planning, regulation, enforcement, technical innovation, and promotion of the understanding of air quality issues. The clean air strategy of the YSAQMD includes the preparation of plans for the attainment of ambient air quality standards, adoption and enforcement of rules and regulations concerning sources of air pollution, and issuance of permits for stationary sources of air pollution. The YSAQMD also inspects stationary sources of air pollution and responds to citizen complaints, monitors ambient air quality and meteorological conditions, and implements programs and regulations required by the FCAA, FCAAA, and the CCAA.



As stated in Section 4.3 of the LRDP EIR, an impact is considered significant if the project would:

< Cause or contribute substantially to existing or projected violations of state or federal criteria air pollutant standards;

< Result in exposure of sensitive receptors to substantial pollutant concentrations; or

< Result in exposure of sensitive receptors to unpleasant odors.

Whether a project’s criteria pollutant emissions would cause or contribute substantially to ambient air quality violations is most accurately evaluated through air quality modeling. However, for certain pollutants and emission sources, air quality modeling is not feasible. In lieu of modeling, emission thresholds are often used. If a project’s emissions exceed one or more thresholds, the project is considered to have a significant impact and should be mitigated to the extent feasible. In the YSAQMD, the emission thresholds for criteria pollutants are assumed to equal the YSAQMD’s emission offset requirement thresholds (Regulation III, Rule 3.4), which are 550 pounds per day of CO, and/or 82 pounds per day of volatile organic compounds (VOCs), oxides of nitrogen (NOx), oxides of sulfur (SOx), or respirable particulate matter (PM10).


The air quality analysis for the WWTP Expansion Project is tiered from the discussion presented in Section 4.3 of the 2003 LRDP EIR. Additional analysis presented here focuses on the criteria pollutant effects associated with operation of the expanded WWTP and includes emissions associated with predicted increases in vehicle operations, as well as emissions attributable to the wastewater treatment processes.

Emissions of VOCs, NOx, SOx and PM10 at the WWTP are primarily associated with the operation of mobile sources, such as sludge haul trucks. WWTP’s may potentially contain any


number of constituents, including a long list of VOCs. However, few VOCs are typically present in sufficiently high concentrations within the wastewater liquid or solids to be of regulatory interest.

Mobile source emissions were estimated based on emission factors obtained from the Emfac2002 emissions model. VOC emissions associated with the wastewater treatment processes were estimated using emission factors obtained from the Tri-TAC Guidance Document on Control Technologies for VOC Air Emissions from POTWs. The Tri-TAC guidance document presents recommended methodologies for evaluating emissions and controls specific to each of the primary wastewater treatment processes (e.g., headworks, grit removal, secondary clarifiers, etc.) The Tri-TAC guidance document provides both concentration-based and flow-based emission factors. Flow-based emission factors, in comparison to concentration-based emission factors, are typically considered to generate a more conservative estimation of emissions (i.e., overestimate). Although concentration-based emission factors may be more accurate, flow-based emission factors are recommended when estimates of VOC constituents within the waste stream are not known or could potentially change, such as when conducting an analysis of future plant operations, or when final designs have not yet been completed.

WWTP emissions estimates presented in the previously prepared LRDP EIR were based, in part, on concentration-based emission factors. To ensure a conservative analysis of WWTP emissions, VOC emissions estimates presented in this EIR were evaluated using flow-based emission factors. Consequently, the VOC emissions estimates presented in this EIR are expected to be slightly higher than those presented in the previous LRDP EIR. WWTP emissions were estimated by the UC Davis Office of Environmental Health and Safety for existing, proposed project (year 2013), and cumulative (year 2017) scenarios, based on average dry weather flow rates. This modeling approach is consistent with the YSAQMD-recommended quantification protocol. Additional modeling may need to be conducted, once final design has been completed, to provide a more detailed quantification of VOC emissions and for determination of specific control technologies to be employed, as part of the YSAQMD permitting process. This is common in the final design process and would not substantially change the emissions analyzed in this Draft EIR.


Impacts Adequately Analyzed at the LRDP Level or Not Applicable to the Project

As determined in the Tiered is for the project, the potential short term air quality impacts associated with construction activities, including high concentrations of PM10 and exhaust pollutants emitted from construction equipment, were adequately analyzed in the 2003 LRDP EIR (LRDP Impact 4.3-3) and were found to be significant and unavoidable even with implementation of LRDP Mitigation 4.3-3(a) (requiring campus construction contracts to include measures to reduce fugitive dust impacts) and 4.4-3(c) (requiring control measures to reduce emissions of ozone precursors from construction equipment exhaust). This impact was fully addressed in the Findings and Overriding Considerations adopted by The Regents in connection with its approval of the 2003 LRDP. No conditions have changed and no new information is available because certification of the 2003 LRDP EIR that would alter this previous analysis.


The 2003 LRDP EIR concluded that development under the 2003 LRDP would not exceed health risk standards and that impacts associated with toxic air contaminants (TACs) would be less than significant (2003 LRDP Impact 4.3-5). Expansion of the WWTP was considered in the health risk assessment, assuming that emissions from the WWTP would increase by 50% through 2015-16 with expansion of the WWTP. The proposed project would increase the plant’s treatment capacity from 2.7 mgd ADWF to 3.8 mgd ADWF, an operational increase of 41%. Therefore, the WWTP assumptions included in the 2003 LRDP EIR’s TAC analysis remain valid. Consistent with the 2003 LRDP EIR, the project’s impact associated with TAC generation would be less than significant. The Tiered IS addressed this issue.

Also identified in the Tiered IS, the 2003 LRDP EIR specifically addressed odor impacts associated with the expansion of the campus WWTP and concluded that there are no receptors located near the WWTP, that the proposed project would not create objectionable odors affecting a substantial number of people, and that the impact would be less than significant (2003 LRDP EIR Impact 4.3-4).

Project Level Impacts

Impact 4.3.1. Criteria Pollutants. Routine activities at the WWTP site would result in increased levels of operational emissions of criteria air pollutants, but increases would be minor. This impact is considered less than significant.

The proposed project would not introduce additional employees at the WWTP, so it would not generate additional daily traffic and associated vehicular emission sources. As presented in Table 4.3-3, the proposed project would slightly increase annual vehicle trips associated with transfer of dried biosolids to a local landfill per year. Existing operations currently generate approximately 23 haul truck trips per year. Annual haul truck trips are anticipated to increase by five trips, to approximately 28 trips, when the proposed project is operating at full capacity in 2013. Under full buildout of the treatment plant (in 2017), trips would increase by 13 per year to approximately 36 per year. In addition, the proposed project and cumulative buildout of the plant would continually increase flows through the WWTP and the area of treatment facilities. As previously discussed, treatment processes at the plant are a source of air emissions, the primary emission being VOCs.

Emissions were calculated for existing, proposed project (year 2013), and cumulative (year 2017) conditions. Emissions estimates associated with the various treatment process are presented in Table 4.3-4. Combined estimates, including predicted net increases in mobile and treatment process emissions, are summarized in Table 4.3-5.

Based on the analysis conducted, the proposed WWTP expansion project would result in a net increase in treatment process emissions of approximately 1.1 lb/day by year 2013 and approximately 1.8 lbs/day by year 2017, in comparison to existing conditions. Although truck trips associated with the hauling of sludge are anticipated to increase slightly, reductions in emissions associated with anticipated improvements in vehicle and fuel technologies are anticipated to largely offset corresponding increases in mobile source emissions. As depicted in


Table 4.3-4, net increases attributable to the proposed project would be well below YSAQMD’s significance thresholds. As a result, this impact is considered less than significant.


Table 4.3-3 Vehicular Emissions

VOC NOX PM10 CO SOX Emfac2002 Emission Factors (2004summer): 0.652 12.539 0.348 2.454 0.188

Emfac2002 Emission Factors (2004winter): 0.652 15.085 0.348 2.454 0.188 Emfac2002 Emission Factors (2013summer): 0.416 7.317 0.22 1.561 0.021

Emfac2002 Emission Factors (2013winter): 0.416 8.802 0.22 1.561 0.021 Emfac2002 Emission Factors (2017summer): 0.270 3.772 0.154 1.092 0.021

Emfac2002 Emission Factors (2017winter): 0.000 4.538 0.154 1.205 0.021 Emfac2002 emission factors based on average temperatures of 40 and 85 deg.F., for winter and summer conditions, respectively; 50 percent humidity; 40 mph avg. speed.

Scenario # Annual

Round Trips Miles/Tri

p Annual Miles

Traveled

Avg. Daily Miles

Traveled VOC NOX PM10 CO SOX Year 2004 23 30 690 1.89 0.003 0.058 0.001 0.010 0.001 Year 2013 51 30 1,530 4.19 0.004 0.074 0.002 0.014 0.000 Year 2017 59 30 1,770 4.85 0.001 0.044 0.002 0.012 0.000


4.3-2 Criteria Pollutants. Cumulative development in the region, in conjunction with the proposed WWTP and 2003 LRDP development, would result in increased emissions of criteria pollutants. This impact is considered significant and unavoidable.

The 2003 LRDP EIR found that implementation of the 2003 LRDP, in conjunction with other regional development, would contribute to emissions of criteria pollutants for which the region is in non-attainment status and could hinder attainment efforts (LRDP Impact 4.3-6). The YSAQMD has accounted for a certain amount of regional growth in the existing Sacramento Regional Clean Air Plan. This plan is currently being updated to extend beyond the year 2005, and campus growth under the 2003 LRDP will be incorporated in the plan update. LRDP Mitigation 4.3-6, requires implementation of LRDP Mitigation 4.3-1 (a-c), which provide for vehicular and area source measures. None of the measures listed which include carpooling, alternative fuel vehicles, use of solar water heaters, etc., would apply to the proposed project (the project does not include new employees, water heaters, etc.), so they are not listed here. However, these measures would apply to other campus development contemplated in the 2003 LRDP and would reduce cumulative emissions. Because the YSAQMD remains a nonattainment area for ozone, the 2003 LRDP EIR considered this cumulative impact significant and unavoidable.

Admi

nistra

tive D

raft

EIR

ED

AW

Camp

us W

WTP

Expa

nsion

Pro

ject

4.3-1

1 Ai

r Qua

lity

Tab

le 4

.3-4

U

C D

avis

WW

TP

Ann

ual T

reat

men

t Pro

cess

Em

issi

ons

Sum

mar

y

Exis

ting

Pla

nt

Prop

osed

Exp

ansi

on to

20

13

Pro

pose

d Ex

pans

ion

to

2017

So

urce

Em

issi

on

Fact

or

(lb/y

r/m

gd)

Influ

ent F

low

(mgd

) Nu

mbe

r of

Units

Estim

ated

VOC

Em

ission

s (lb

/yr)

Influ

ent F

low

(mgd

) Nu

mbe

r of

Units

Es

timat

ed V

OC

Emiss

ions

Influ

ent F

low

(mgd

) Nu

mbe

r of

Units

Es

timat

ed V

OC

Emiss

ions

Preli

min

ary T

reat

men

t H

eadw

orks

0.

1 1.

7 1

0.17

3.

81

2 0.

762

4.3

2 0.

86

Biolo

gical

Trea

tmen

t M

echa

nica

lly A

erat

ed A

ctiv

ated

Slu

dge

30

1.7

3 15

3 3.

81

3 34

2.9

4.3

4 51

6 Po

st Bi

ologic

al Tr

eatm

ent

Seco

ndar

y C

lari

fiers

12

1.

7 2

41

3.81

3

137.

16

4.3

3 15

4.8

Effl

uent

Filt

ratio

n 0.

6 1.

7 3

3.1

3.81

5

11.4

3 4.

3 5

12.9

U

V D

isin

fect

ion

0.9

1.7

2 3.

1 3.

81

3 10

.287

4.

3 3

11.6

1 So

lids H

andli

ng

Ope

n So

lids

Han

dlin

g 10

1.

7 3

51

3.81

4

152.

4 4.

3 5

215

Ann

ual V

OC

Em

issi

ons

(lbs)

25

1 65

5 91

1 N

ote:

Em

issio

n Fa

ctor

s are

bas

ed o

n flo

w-b

ased

em

issio

n fa

ctor

s obt

aine

d fr

om T

ri-T

AC G

uida

nce

Doc

umen

t on

Con

trol

Tec

hnol

ogy

for

VO

C A

ir E

miss

ions

from

PO

TW

s (M

arch

19

94).

Ref

er to

App

endi

x C

for

emiss

ion

calc

ulat

ions

. So

urce

: U

C D

avis

Offi

ce o

f Env

iron

men

tal H

ealth

and

Saf

ety,

200

4

Tab

le 4

.3-5

U

C D

avis

WW

TP

Est

imat

ed A

vera

ge D

aily

Em

issi

ons

Sum

mar

y E

xist

ing

Plan

t Pr

opos

ed E

xpan

sion

to 2

013

Prop

osed

Exp

ansi

on to

201

7 So

urce

VO

C NO

X PM

10

CO

SOX

VOC

NOX

PM10

CO

SO

X VO

C NO

X PM

10

CO

SOX

Tre

atm

ent P

roce

sses

1.

01

- -

- -

1.79

-

- -

- 2.

50

- -

- -

Hau

l Tru

cks

0.00

3 0.

058

0.00

10.

010

0.00

10.

004

0.07

40.

002

0.01

40

0.00

10.

044

0.00

20.

012

0 T

otal

Em

issi

ons

1.01

3 0.

058

0.00

10.

010

0.00

11.

794

0.07

40.

002

0.01

40

2.50

10.

044

0.00

20.

012

0 N

et I

ncre

ases

(In

Com

pari

son

to E

xist

ing

Con

ditio

ns)

0.78

0.

02

0 0

0 1.

49

-0.0

1 0

0 0

YSA

QM

D S

igni

fican

ce T

hres

hold

s 82

82

82

55

0 82

82

82

82

55

0 82

Si

gnifi

cant

Im

pact

s?

Non

e N

one

Not

e:

Emiss

ions

for

trea

tmen

t pro

cess

es a

re b

ased

on

annu

al V

OC

em

issio

ns e

stim

ates

, as p

rese

nted

in T

able

4.3

-3; a

ssum

es 3

65 a

nnua

l ope

ratio

n da

ys.

Mob

ile so

urce

em

issio

ns

wer

e ca

lcul

ated

usin

g Em

fac2

002

emiss

ion

fact

ors a

nd a

ssum

e 23

exi

stin

g an

nual

hau

l tru

ck tr

ips,

51 a

nnua

l tri

ps b

y ye

ar 2

013,

and

59

annu

al tr

ips b

y ye

ar 2

017.

To

be

cons

erva

tive,

hau

l tri

ps w

ere

calc

ulat

ed b

ased

on

a ro

und-

trip

dist

ance

of 3

0 m

iles.

Ref

er to

App

endi

x C

for

emiss

ion

calc

ulat

ions

. So

urce

: U

C D

avis

Offi

ce o

f Env

iron

men

tal H

ealth

and

Saf

ety

2004

; ED

AW 2

004

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