4 ENVIRONMENTAL SETTING, IMPACTS, AND MITIGATION …

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.

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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

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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.

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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

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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.

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