david s. warne

November 28, 2021

Patrick M. PalmerNew York State Department of HealthBureau of Public Water Supply Protection1110 ESP Corning TowerAlbany, NY 12237-0622

Katie LynchUnited States Environmental Protection Agency - Region II290 Broadway - 24th FloorNew York, NY 10007-1866

Dear Mr. Palmer and Ms. Lynch,

Enclosed is the DEP Response to the NYSDOH/USEPA Comments on 2017 FAD Deliverables submitted in July and August, 2021.

As always, if you have questions about these comments responses or other aspects of the City’s watershed protection efforts, please do not hesitate to contact me.

Sincerely,

David S. WarneAssistant Commissioner

c: T. Snow, DEC

David S. Warne

Digitally signed by David S. Warne Date: 2021.11.24 11:13:26 -05'00'

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DEP Response to NYSDOH/USEPA Comments on the FAD Deliverable Reports Submitted: July 2021

Response Date: November 30, 2021

4.2 Land Acquisition Program As required by the 2017 FAD, the City submitted the semi-annual report on Land Acquisition Program (LAP) activities and status for the period January 1, 2021 through June 30, 2021. The City reported that, due to the ongoing COVID-19 pandemic, no outgoing solicitation took place during the period. Incoming solicitation directly from landowners accounted for 2,172 acres in the core LAP. The City reports that, at the halfway point of the seven-year solicitation period, the LAP has solicited 126,983 acres (36% of the 350,000 FAD goal).

DEP Response: Comment noted.

During the reporting period, the program signed five purchase contracts covering 204 acres and no conservation easements. Table 1 indicates that the Streamside Acquisition Program and Flood Buyout Program are more effective tools for protecting stream buffers and wetlands on a per acre-acquired basis than the fee simple core program.


4.9 East of Hudson Non-point Source Pollution Control The 2017 FAD required the City to complete a Video Sanitary Sewer Inspection by March 31, 2021. This due date was not met. In June, the City reported that it is coordinating with the selected contractor (National Water Main) to validate its subcontractor (Allstate Mapping & Layout, LLC). Once mobilized, it is estimated that the field activities can be completed in six weeks. The City shall continue monthly updates regarding the missed milestone completion date for the Video Sanitary Sewer Inspection until field activities are complete and a report of findings is drafted.


5.1 Watershed Monitoring Program As required by the 2017 FAD, the City submitted the Watershed Water Quality Annual Report for 2020. The 2020 global pandemic necessitated reduced monitoring for some regular watershed water quality sampling activities; however, NYSDOH notes that the reduced monitoring schedule did not impact compliance with FAD requirements. As of October 4, 2021, most of the sampling has returned to pre-pandemic levels. NYSDOH and USEPA have the following questions/comments: On page 13 (Section 2.3), the discussion seems to equate runoff (flows over the grounds surface into a stream) with discharge (total stream flows) that includes baseflow (shallow groundwater

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flows into a stream). This could lead to some confusion, particularly if baseflow is not considered when conceptualizing SWAT models and DBP precursor movement.

DEP Response: We recognize the mismatch between the provided definition for “runoff”, which excludes baseflow, and the “runoff” results provided in Figure 2.2 which includes baseflow. To avoid confusion, in future reports we will adjust the text and Figure 2.2 to discuss these flows as “areal normalized discharge” and not as runoff.

0 (Section 3.7), do reservoir nutrient benchmark exceedances include samples taken from the hypolimnion? These concentrations have no impact on productivity unless nutrients move from the hypolimnion into the epilimnion, at which point they would be expressed in the concentrations measured there. It would be more informative if phosphorus concentrations were considered separately for the epilimnion and hypolimnion (and potentially the tailwaters too), as pelagic epilimnion phosphorus concentrations best describe and predict trophic state.

DEP Response: All routine monitoring samples are included (all depths including the hypolimnion). Comment noted and will be taken into consideration for next year’s report.

On page 49, Section 3.14.3 describes the Croton System taste and odor issue, which occurred in 2019 and again in 2020and is expected to continue. Has the City considered expanding this monitoring in upstream reservoirs (e.g., to Cross River) to investigate the biological causes (e.g., from phytoplankton or decaying hydrilla), and explored potential management options (e.g., using algaecides/herbicides)?

DEP Response: DEP continues to study the Croton System taste and odor issue, which includes expanding monitoring to include upstream reservoirs. DEP is exploring the use of copper sulfate treatments in the Croton System to manage the growth of algae to mitigate the taste and odor issues.

On Page 52 (Section 3.14.6), regarding Aqueduct Leak Monitoring, the first paragraph provides a description of sampling a suspected aqueduct leak at the St. Elmo Siphon against water collected at EARCM. The results indicated that there was some indication that the source was leaking aqueduct water, but the results were not conclusive. Paragraph 4 indicates that a similar procedure was performed near Shaft 9, where the comparison indicated that Catskill Aqueduct water is leaking into the manholes surrounding Shaft 9. What were the specific metrics that were found at Shaft 9, but not at the St. Elmo Siphon?

DEP Response: The primary metrics for identifying the presence of an aqueduct leak were specific conductivity and phytoplankton. When the leak shows similarities to samples at EARCM, that is used as our indicator for a likely reservoir contribution. A sample from Shaft 9 had a count of 220 ASU/100 mL for Fragilaria suggesting the presence of aqueduct water, while only trace amounts of phytoplankton were found in the St. Elmo Siphon sites. Due to the low presence of diatoms at the St. Elmo Siphon sites (Melosira, Cyclotella, and Navicula) we did not rule out an aqueduct leak, but

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specific conductivity was markedly higher than at EARCM, so we did not get a definitive answer from our initial investigation.

On page 60 (Section 4.2), NYSDOH notes that for year 2020, water quality at Kensico Reservoir was in compliance with the turbidity and fecal coliform criteria of the Surface Water Treatment Rule. The single sample maximum compliance value for raw water turbidity at DEL18DT was 1.3 NTU, and only two fecal coliform samples at DEL18DT exceeded 20 CFU/ 100 mL.


On pages 72-73 (Section 4.5.1), the report discusses the success of the modified sluicegate closure approach for reducing bryozoan growth at Shaft 18. Has this approach been implemented in 2021?

DEP Response: Yes, the same approach was implemented in 2021; however, required activities and operations did not allow for the same flexibility of sluicegate closures this year. The shoreline stabilization project proximal to Shaft 18, and the changing of reservoir operations required during and after storm events, limited the opening and closing of some sluicegates. Specifically, sluicegate 22 (closest to the shoreline) remained closed much of the season requiring one of the remaining gates to always be open compared to 2020. As a result, there was more growth of bryozoan colonies (in size and abundance) in 2021; but divers were contracted and removed the colonies the week of October 18 without incident.

On page 76 (Section 4.5.2.4), regarding the potential septic discharge to Whippoorwill Creek, has there been any additional monitoring following the FLIR scan of the area?

DEP Response: Additional sampling at the Whippoorwill Creek neighborhood was performed in 2021 once monitoring resumed after COVID reductions. A water quality survey was performed at five locations on June 1, 2021, which included both neighborhood stream and storm drain water. Fecal coliform results ranged from 340 to >3000 and, as in the first survey (March 2020), all samples were positive for moderate to high levels of the Bacteroides human marker (HF183). Watershed Protection Program (WPP) staff performed ground surveys and identified residences with potential septic system issues. Three dye tests have been performed to date and all were positive for dye entering the local watercourse and the storm system. WPP is requiring the submission of remediation plans for each of the failing systems.

On page 77 (Section 4.5.2.5), regarding Supply Conduit #8, NYSDOH notes that annually for at least the first three years following the conduit’s return to service, an inspection will be performed to ensure the integrity of the epoxied surface and expansion joints. The first of these inspections occurred in Fall 2021.


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Figure 6.2 on page 113 (Section 6.2.2) shows the estimated change in manure P production in the Cannonsville watershed. The report notes that the observed decrease reflects changes in farm animal count. Please provide more information on how the amount of manure P was estimated. The trend since around 2005 is flat, though the expectation was that it should have decreased as more dairy operations have shifted from dairy to beef resulting in fewer animal units and perhaps different spreading patterns coupled with more precision feeding.

DEP Response: The total amount of manure P was estimated based on the number of dairy and beef cattle in the watershed and the typical amount of manure produced by each animal category per day. From the total amount of manure produced per year, manure P in dissolved (soluble P) and particulate (organic P) forms were estimated for each animal category. Dairy manure P content used is 0.5% soluble and 0.3% particulate whereas beef manure P content is 0.4% soluble and 0.7% particulate (ASAE, 1998; Arnold et al. 2013). Soluble form of manure P shows a slow decreasing trend in Figure 6.2 whereas particulate form and total manure P did not follow this trend likely due to the increase in beef cattle population and higher content of particulate P in beef manure than in dairy manure. This topic is discussed in the NASEM (2020) report (page 156-157).

Section 6.2.2 does not specifically describe an analysis of the LAP. Admittedly this could be difficult and would involve many of assumptions regarding the amount, location, and type of land development that has been prevented currently and in the future. Would coarse hypothetical buildout scenarios be helpful in evaluating the historical and existing LAP and potential future tradeoffs between core LAP and SAP?

DEP Response: A conceptual or hypothetical scenario of potential tradeoff between LAP and SAP would look similar in pattern as the buffer-planting scenarios presented in Figure 6.5 although the percent reduction in nutrient loading or impact on water quality will be different and uncertain depending on the assumptions. With detailed spatial information on historical LAP such as location, type of land, and acreage such analysis could be considered.

On page 115 (Section 6.2.3), how were the observed DP loads calculated on figure 6.3, and why was DP used rather than TP?

DEP Response: Observed DP loads presented in Figure 6.3 are average daily loads by month. For the calibration/validation period (2001-2010), data from the NYSDEC monitoring program that includes daily sampling including storm events was used. Daily loads were estimated using daily concentrations of DP and daily flows. Data for 2011-2019 are from the DEP monitoring program that were collected at a lower and varying frequency. The FLUX32 program was used to estimate loads for missing days using C/Q regression and generate a continuous time series of observational daily loads.

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Following up on our earlier modeling assessments in 2006 and 2011 done as part of a eutrophication-modeling framework in the Cannonsville Reservoir we focused on dissolved phosphorus (DP). DP is the fraction of TP that is readily available for phytoplankton growth and subsequent eutrophication. In the context of impact on eutrophication in the Cannonsville Reservoir, the loading reductions in DP give a quicker response and best representation of management impacts.

On page 116 (Section 6.2.3), it is estimated that addressing point sources has reduced the total NPS load by 49% (originally it was 50% and now it is 1%). Could similar calculations of the percentage of total NPS reductions achieved by the other programs be done, and could this be done on a kg/$ basis?

DEP Response: The first statement is correct if the baseline reference year is 1992 (see Fig 6.1) and will change depending on the baseline reference year/period considered. If the period 1992-2000 is considered as baseline reference, the contribution of point sources for that period would be ~26% of the total or ~3590 kg yr-1. Reductions achieved by other programs implemented over the years and changes to farms on NPS loading is estimated to be ~35% compared to the 1990s. This is based on an estimated change in annual contribution from nonpoint sources from ~13,400 kg yr-1 for the baseline period to about ~8700 kg yr-1 for the current period, a net reduction of ~4700 kg yr-1. Unlike point source contributions that can be estimated through direct measurement, a watershed model is required to estimate reduction or change in contribution from nonpoint/diffuse sources taking into consideration the impact of differences in climate and hydrology over the assessment period Funding information for PS and NPS programs can be found in NASEM (2020) report (Table 1-1, page 18-19) to estimate reductions per dollar basis.

On page 117 (Section 6.2.3), the Impact of Septic Remediation and Replacement section is confusing. For the period of 2010-2019 the number of failing septic tanks was estimated at 11%. Is this figure based on with or without the septic repair and replacement program in place (i.e. what are the base and current conditions)? How are the load reductions on Figure 6.3 calculated, and are they annual or total for the period?

DEP Response: The number of failing septic systems contributing to stream nutrient load was based on the total septic systems repaired since 2009 that are within 300 feet of a waterbody (see page 114). The scenario simulated assumed that no repair was performed on failing septic systems and was compared to a reference scenario for the same period with all septic systems functioning properly, to estimate contribution from failing septic systems. Table 6.3 is the estimated cumulative contribution from failing septic systems (if not repaired) for the period 2010-2019 or reduction in loading achieved through septic repairs over a 10-year period.

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On page 118 (Section 6.2.3), the analysis of various scenarios of Vegetated Buffers on Agricultural Land provides valuable information. NYSDOH would be interested in seeing a similar analysis expanded to other programs. Noting that model output suggested winter rye cover crops may actually increase dissolved phosphorus loads in some locations, has the City considered additional sampling to support this conclusion? This has implications for the other evaluated programs where management/treatment locations and soil hydrology are important. How can siting constraints identified via these modeling scenarios best be shared with other areas of the City’s watershed protection program?

DEP Response: Results of winter rye cover cropping impact on dissolved phosphorus are based on model scenarios and are consistent with information in the literature. However, it is very well possible that the exact location of cover cropping practiced in the watershed is different from the model scenarios. One of the studies cited (Kleinman et al. 2005) is based on a field study in the Cannonsville watershed. While additional sampling to support the modeling analysis by the City may be difficult due to time and other resources required, we would consider seeking opportunities to collaborate with an external partner in such research projects. The overall benefits of cover cropping (reduction in sediment and TP in runoff) may outweigh any potential negative impact. Sensitive areas for BMP implementation identified in this modeling analysis are consistent with prior knowledge on saturation excess runoff mechanism in the region. This has been taken into consideration in watershed modeling, and existing watershed protection programs and practices such as avoiding manure spreading in saturated and wet areas of the landscape, and cattle exclusion from near stream areas. Targeting the dominant runoff generating areas is applicable to most BMPs where the goal is to minimize nutrient export in runoff. These are areas with high topographic wetness index (TWI) represented in the model through wetness class delineation. Maps of topographic wetness index that shows the likelihood of a location to saturate and generate runoff will be shared with DEP’s watershed program staff for further consideration.

On page 126 (Section 6.3.4), Figures 6.7 and 6.8 do not appear to have printed correctly. Please reformat and provide with the response to comments.

DEP Response: Figures 6.7 and 6.8 lost formatting while saving the Word® formatted document to a pdf format. The correct figures are attached.

On page 134 (Section 6.4.1), Figure 6.13 shows the comparison of observed and predicted turbidities for Cannonsville Reservoir withdrawals for the period 2011-2019. Please clarify what the dashed trendline “predicted (diversion=off)” represents. Is the model suggesting that these turbidity spikes would have occurred if not for diverting Cannonsville water to Rondout Reservoir?

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DEP Response: The dashed line in Figure 6.13 shows the predicted turbidities for the time intervals when no water was being diverted from Cannonsville to Rondout Reservoir. In other words, if water were to be diverted, it would have seen turbidity levels indicated by the dashed line.

On page 138 (Section 6.6), the report states: "Two greenhouse gases emission scenarios (RCP 4.5 and RCP 8.5) . . . were considered." However, neither Figure 6.17 not Table 6.8 indicate which RCP was used in projecting the presented trends.

DEP Response: The two RCPs were combined in generating Figure 6.17 and Table 6.8. Results shown in Figure 6.17 and Table 6.8 are based on multi-model, multi-scenario ensemble obtained from 20 global climate models’ output for each of the two greenhouse gases emission scenarios, thus giving a total of 40 likely outcomes of future climate. This approach provides a robust representation of the variability in the future climate.

On page 144 (Section 6.7), the report states: “Figure 6.18c and d show trends of these extreme flows; however, there is clearly a seasonal split between peak flows occurring in late-fall and mid-winter, possibly resulting from different sources, such as extreme precipitation in the fall or snowmelt”. It may be beneficial to split the dataset used for the maximum flow in Figure 6.18d into “Late Fall” and “Spring and Winter” and re-graph with separate trendlines.

DEP Response: Comment noted. Accordingly, the revised Figure 6.18d is attached. As mentioned in the report, DEP is currently reviewing the analyses completed for meteorological, streamflow and water quality indicators, and considering revisions to the methodology such as additional trend metrics or aggregation of individual indicators.

In last year’s report (page 55; Section 3.14.9), NYCDEP provided the following response regarding the special investigation on Conversion of Septic to Sewer Evaluation: “The plan calls for the data to be analyzed and a report prepared following the post-construction monitoring period. Sampling was terminated in 2020, and report will be forthcoming.” Please provide a follow-up to this comment.

DEP Response: A report was drafted in 2021 and the final version is currently under review.

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DEP Response to NYSDOH/USEPA Comments on the FAD Deliverable Reports Submitted: August 2021

4.6 Stream Management Program As required by the 2017 FAD, the City is required to convene one of two semi-annual progress meetings of the Stream Management Program by August 30th. The meeting took place by video conference on August 12, 2021.


4.9 East of Hudson Non-point Source Pollution Control The 2017 FAD required the City to complete a Video Sanitary Sewer Inspection by March 31, 2021. This due date was not met, and NYSDOH requested monthly status updates until it is completed. The City reported in August that National Water Main began coordinating with municipal officials on staging and traffic control in the affected Towns on August 2, 2021 and was scheduled to commence with targeted cleaning and inspection of sewers in early September. Currently, the selected contractor (National Water Main) expects it will take 12 weeks for the completion of all field activities after work begins.


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Figure 6.18d. Timing of peak flow, as day of year, at USGS Gage 1350000 (Schoharie Creek at Prattsville, NY), 1902-2020.

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1900 1920 1940 1960 1980 2000 2020

Tim

ing

of a

nnua

l 1 d

ay m

axim

um fl

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yearSource: USGS

Spring Max Flow Timing: 44.6 Day Increase; R² = 0.105Winter Max Flow Timing: 2.9 Day Decrease; R² = 0.0004

david s. warne

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