4 ENVIRONMENTAL SETTING, IMPACTS, AND MITIGATION MEASURES

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1 4.0 INTRODUCTION 4 ENVIRONMENTAL SETTING, IMPACTS, AND MITIGATION MEASURES 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. University of California, Davis 4-1 Environmental Settings, Impacts, and Mitigation Measures

2 4.0.1 SCOPE OF THE EIR 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 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 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 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 Pursuant to Section 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 Environmental Settings, Impacts, and Mitigation Measures 4-2 University of California, Davis

3 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 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 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 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 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. University of California, Davis 4-3 Environmental Settings, Impacts, and Mitigation Measures

4 4.1 HYDROLOGY AND WATER QUALITY 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 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 ). 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 to ). 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 ). 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 University of California, Davis Hydrology and Water Quality

5 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 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 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 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 ( ) 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 ( ). Data for 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. Hydrology and Water Quality University of California, Davis

6 Year Table Putah Creek Water Quality Downstream from WWTP Outfall Parameter (units) and annual mean values DO (mg/l) ph (standard units) Turbidity (NTU) Temperature ( C) Measurements from years when previous campus WWTP was operational a Measurements from years with current campus WWTP a 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 (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 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 shows a comparison of University of California, Davis Hydrology and Water Quality

7 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 Summary of WWTP Effluent Monitoring Results for Conventional Parameters Parameter a (units) Measurements (mean) from years when previous campus WWTP was operational b BOD (mg/l) TSS (mg/l) EC (µmhos/cm) ph (standard units) Flow (mgd) Parameter (units) Measurements (mean) from years with current campus WWTP b BOD (mg/l) TSS (mg/l) Ammonia (mg/l-n) <0.5 <0.5 EC (µmhos/cm) ph (standard units) Temperature ( C) Flow (mgd) 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). Hydrology and Water Quality University of California, Davis

8 4.1.3 REGULATORY SETTING Section (pp to ) of the 2003 LRDP EIR and the Tiered IS (pp ) 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 et seq.), and Title 22 wastewater reclamation guidelines of the California Health and Safety Code (CCR, Section 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.). University of California, Davis Hydrology and Water Quality

9 4.1.4 ENVIRONMENTAL IMPACTS AND MITIGATION MEASURES 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 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 Hydrology and Water Quality University of California, Davis

10 permit for the WWTP, as well as 303(d)-listed parameters (mercury). The priority parameters are listed in Table Aluminum Ammonia Arsenic Copper Cyanide Dichloromethane Dioxin Iron Lead Mercury Table Priority Parameters Temperature Nitrate + Nitrite ph Phosphorus Electrical Conductivity Total Coliform Residual Chlorine Toxicity Turbidity 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 yearto-year was performed. Using concentrations of EC from the 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 University of California, Davis Hydrology and Water Quality

11 umhos/cm Upstream Monitoring Station (R1) 493 Effluent Downstream Monitoring Station (R2) Source: Larry Walker Associates 2004 (based on UC Davis WWTP Data) EXHIBIT Monthly Average Electrical Conductivity (March 2000 July 2004) Campus WWTP Expansion Project P 4T /04 08/04

12 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 period are tabulated in Table The data are described in the pollutant-by-pollutant discussion provided later. Table 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 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 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 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. University of California, Davis Hydrology and Water Quality

13 Table 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 Ammonia (mg/l-n) 1.96 a Arsenic NA Chlorine, Residual (mg/l) < b Chromium, Total Copper 9.7 c Cyanide Dichloromethane Dioxin (pg/l) <25 12 e EC (µmhos/cm) Hardness (mg/l CaCO 3 ) NA Iron Lead 3.6 c f Mercury NA Nitrate + Nitrite (mg/l-n) f ph (standard units) Phosphorus, Total (mg/l-p) NA Temperature ( C) NA f Total Coliform (MPN/100 ml) Turbidity (NTU) 2 d 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 Hydrology and Water Quality University of California, Davis

14 Parameter Table WWTP Effluent Water Quality Summary for 2002 Results in µg/l unless stated otherwise Mean Median Min Max Aluminum Ammonia (mg/l-n) Arsenic Chromium, Total Copper Cyanide Dichloromethane - - <2 <2 Dioxin (pg/l) - - <25 12 EC (µmhos/cm) Hardness (mg/l CaCO 3 ) Iron Lead Mercury Nitrate + Nitrite (mg/l-n) ph (standard units) Phosphorus, Total (mg/l) Temperature ( C) Total Dissolved Solids (mg/l) Turbidity (NTU) 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. University of California, Davis Hydrology and Water Quality

15 Table WWTP Effluent Data ( ) 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 ND 4,4'-DDD ND 4,4'-DDE ND 4,4'-DDT ND Acrylonitrile ND Aldrin ND Atrizine - ND Benzidine ND Benzo(k)Fluoranthene ND Bis(2-Chloroethyl)Ether ND Cadmium 2.65 ND Carbon Tetrachloride 0.25 ND Chlordane ND Chlorpyrifos - ND Dibromochloropropane (DBCP) - ND Diazinon - ND Dichlorobromomethane 0.56 ND Diquat - ND Ethylene dibromide - ND Heptachlor ND Heptachlor Epoxide ND Hexachlorobenzene ND Hexachlorocyclopentadiene 240 ND Indeno(1,2,3-cd)Pyrene ND N-Nitrosodimethylamine ND N-Nitrosodi-n-Propylamine ND Polychlorinated biphenyls (sum of 7) ND Toxaphene ND Source: Larry Walker Associates based on UC Davis WWTP discharge monitoring data. ND = not detected Hydrology and Water Quality University of California, Davis

16 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 Table 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. University of California, Davis Hydrology and Water Quality

17 Table 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 Ammonia (mg/l-n) 0.35 b Arsenic 10 c Chlorine, Residual (mg/l) i - i <0.02 <0.02 Chromium, Total 238 d Copper 10.4 d Cyanide 5.2 e i - i Dichloromethane 4.7 e i - i <2 35 Dioxin (pg/l) e Dissolved Oxygen (mg/l) 5 f EC (µmhos/cm) 900 c Fecal Coliform (MPN/100 ml) 200 f Hardenss (mg/l CaCO 3 ) NA Iron 300 c, g j 203 j 79 j 988 j Lead 3.0 d Mercury 0.05 e Nitrate + Nitrite (mg/l-n) 10 c k ph (standard units) f Phosphorus, Total (mg/l-p) NA Temperature ( C) h k Turbidity (NTU) h 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 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. Hydrology and Water Quality University of California, Davis

18 Parameter Table Upstream Putah Creek (R1) Water Quality Summary for 2002 Results in µg/l unless stated otherwise Mean Median Min Max Aluminum Ammonia (mg/l-n) Arsenic Chromium, Total Copper Cyanide Dichloromethane Dioxin (pg/l) EC (µmhos/cm) Hardness (mg/l CaCO 3 ) Iron Lead Mercury Nitrate + Nitrite (mg/l-n) ph (standard units) Phosphorus, Total (mg/l-p) Temperature ( C) Total Dissolved Solids (mg/l) Turbidity (NTU) 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 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. University of California, Davis Hydrology and Water Quality

19 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 ). The guidance states that a RWQCB may determine it is not necessary to do a complete antidegradation 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. Hydrology and Water Quality University of California, Davis

20 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 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 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 University of California, Davis Hydrology and Water Quality