FRESNO METROPOLITAN FLOOD CONTROL DISTRICT

Capturing stormwater since 1956.

October 19, 2016

Mr. Jay Simi Water Resource Control Engineer California Water Quality Control Board Central Valley Division 11 020 Sun Center Drive, #200 Rancho Cordova, CA 95870-6114

Delivered via email only to: Jay.Simi@waterboards.ca.gov

Dear Mr. Simi,

File 170.64

FRESNO METROPOLITAN FLOOD CONTROL DISTRICT COMMENTS ON PROPOSED 303(D) LIST REVISIONS

The Fresno Metropolitan Flood Control District (District) appreciates the opportunity to provide comments on the proposed revisions to the California Water Code Section 303(d) list of impaired water bodies (303(d) List). We recognize that this evaluation required significant effort from the Central Valley Regional Water Quality Control Board (Regional Water Board) staff to compile a large amount of data and prepare the detailed assessment according to the impairment listing requirements of the federal Clean Water Act (Listing Policy). 1

The District manages the flood control and municipal separate stormwater sewer system (MS4) for the Fresno/Clovis urban area. The District also manages the MS4 National Pollutant Discharge Elimination System (NPDES) permit for discharges to waters of the state, including the San Joaquin River between Friant Dam and Mendota Pool. The District captures and infiltrates the vast majority of rainfall in the service area through an extensive regional basin system that serves more than 95% of the permitted area.

1State Water Resources Control Board. Water Quality Control Policy for Developing California 's Clean Water Act Section 303(d) List. Adopted September 30, 2004 and Amended February 3, 2015. http://www. waterboards.ca.gov/board decisions/adopted orders/resolutions/20 15/020315 8 am - - --endment_ clean_ version. pdf

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5469 E. Olive Ave. • Fresno, CA 93727 • (559) 456-3292 FAX (559) 456-3194 • www.fresnofloodcontrol.org

Years of Service 1956-2016

Mr. Jay Simi October 19, 2016 Page 2

The District has identified several issues with the recommended new decision to list the San Joaquin River between Friant Dam to the Mendota Pool as impaired due to pH.

Evaluation of pH in the San Joaquin River (Friant Dam to Mendota Pool) The District recommends not listing the San Joaquin River (Friant Dam to Mendota Pool) as impaired due to pH (Decision ID 57464), since the evaluation does not address site specific conditions and the conclusion is based upon the use of insufficient data. This unique reach of the San Joaquin River is immediately downstream from a major dam and the dataset used as the basis for the decision extends only through one week (shown in Table 1 below) when much larger continuous datasets are available and likely demonstrate that there is no impairment.

Incomplete Assessment of Site Specific Conditions Streams and rivers in the Central Valley are subject to low flow conditions in the summertime periods, especially in the late summer when dam releases are lower. Slower moving water tends to encourage algae growth, which in turn drives daily cycling of dissolved oxygen and pH. When dissolved oxygen decreases overnight to minimum values in the morning, it can take into the afternoon to recover dissolved oxygen and pH values. The Safe-to-Swim sample collection targets beach areas where algal growth is encouraged by hydraulic conditions. If samples are collected near the shore where stream velocities are lower and algae growth greater than mid-stream, pH swings would be more significant. Moreover, the Basin Plan pH objectives are not protective of a specific beneficial use and are intended to represent "healthy" conditions, when in fact the defmition of "healthy" can be site specific. The forthcoming Statewide Biointegrity Policy is intended to address these very issues.

Insufficient Data Considered The proposed impairment listing is based on five of twelve samples outside of the Basin Plan objective range (i.e., lower than the Basin Plan requirement that "The pH shall not be depressed below 6.5 ... "). The Listing Policy requires a minimum of five samples for an impairment listing. Four of the low pH values occurred on the same day and are essentially a replicated data point characterizing one daily condition in the reach. All of the samples were collected over a one week period and represent the seasonally worst case condition (late summer) for temperature, pH, and dissolved oxygen in a typical year. Four of the five pH values below 6.5 were less than 10% lower, within typical laboratory or field measurement error. The quality control data and equipment calibration records were not included in the SWAMP reports. Moreover, continuous data (i.e., CDEC) are available on this reach of the San Joaquin River, which were not considered in the evaluation.

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Mr. Jay Simi October 19, 2016 Page 3

Table 1. pH Data in the San Joaquin River Provided as the Basis for Impairment Listing

Station Code Station Name Sample Sample Result _ __Da!_e___ Time (std. units)

_ 5~5FRE5Q~_ Los~ _~ak~S_q_un~ X~r:_ls_ _______ _§_/2_7/0~ _ _ _11 :55:0Q_ ____ 7.:_09 __ _ ~45X~~Q? ___ _Fort w_~shin~~-~~-~~h _____ ?d._27/08 _ 1_2:30~90 ---- -~_:_~_? _ ___ _ 545FRE504 FriantCove 8/27/08 11:25:00 6.78 - - ---------------------~----------··--------

545MAD008 Wildwood 8/27/08 13:05:00 7.1 ---- -- - --------545F!ffi502 L_9~!~ake County Park 8/31/08 _____ U__:}5:00 6.07 545FRE503 _Fort ~-a.~!?--~gton Beach___ 8/31/08 12:04:00 6.54 545FRE504 Friant Cove 8/31/08 11:00:00 6.57

- -------------·-·----·------------- ----------······--------------- -·----------------···--545MAD008 Wildwood 8/31108 12:40:00 6.56 -- ------ -- ----- -- ----------- -- - - -__ .. __ ------ - -- - - · ·- ------ - ----

-545F~502 ____ Lost h_ak~ G_o~!):'_ ~ar!c_ _ _ 9/3/08 __ _ } 1 :24~9Q. __ ____ S.f! __ ___ _ -~~~~!!!503 _______ E<?.t:t: .. ~'!~~~g!9_r.!_~~~ch ___ ______ 2~~~0~------- J .. J:?Q_: 00_. _______ _§~2 7 ______ _ 545FRE504 Friant Cove 9/3/08 11 :04:00 6.37 ---~------~---- ----------- ---·- ·-· --~-~ ... --- - --545MAD008 Wildwood 9/3/08 12:15:00 6.43

Noti:the five exceedances (from a dataset of twelve samples) of the water quality objective are shown in-cbc-o-:-ld,-. -

Sections 6.1.5.2 and 6.1.5.3 of the Listing Policy provide specific guidance on spatial and temporal data representativeness. While the sites are more than 200 meters apart, as required by the Listing Policy, the sites are very similar relative to pH conditions (e.g., shading, nutrients, tributary watershed, low velocity beach and recreation locations) and there are no known sources of contaminants or discharges that would cause "unnatural" pH conditions. The Listing Policy also specifies that "Samples used in the assessment must be temporally independent. If the majority of samples were collected on a single day or during a single short-term natural event (e.g., a storm, flood, or wildfire), the data shall not be used as the primary data set supporting the listing decision." While the samples were not collected on the same day, the "Safe to Swim" program is targeting a short term summertime recreational "event", and additional data are available to make a more robust assessment.

In summary, the data used for the assessment do not meet the minimum temporal requirements of the Listing Policy and it is not established that they are sufficiently representative of an impaired beneficial use. Any impairment listing assessment for a general parameter such as pH should consider a wider range of constituents and underlying causes of pH depression.

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Mr. Jay Simi October 19, 2016 Page 4

Please let me know if you have questions regarding our recommendation to not include pH for the San Joaquin River between Friant Dam and Mendota Pool in the revised 2014 303(d) List.

Very Truly Yours,

}~~ Daniel Rourke Environmental Resources Manager

DR/sy

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