Environmental Impact Analysis City of Union City Hydrology and Water Quality 4.8 Hydrology and Water Quality This section describes the environmental and regulatory setting for hydrology and water quality. It also describes impacts on hydrology and water quality that would result from implementation of the project and mitigation for significant impacts where feasible and appropriate. This section is based, in part, on the Updated Summary of Stormwater Infrastructure Modeling prepared for the project by Balance Hydrologics (Appendix 4.8-1), the LID Reduction Narrative Memorandum prepared for the project by CBG Engineers (Appendix 4.8-2), and the Additional Hydraulic Modeling of the Existing Zwissig Way Storm Drain Line by Balance Hydrologics (Appendix 4.8-3).1,2,3 In response to the Notice of Preparation (NOP), comments were received that identified concerns with runoff, off-site drainage patterns, and groundwater resources. The comments are addressed in the environmental analysis in this section. 4.8.1 Existing Conditions 4.8.1.1 Environmental Setting Mean precipitation from the nearest weather station, located in Newark, California, from 1996 to 2016 averaged approximately 14 inches annually. Precipitation in the project area is highly seasonal, with most rainfall occurring between November and March.4 The project site ranges in elevation from approximately 50 feet above mean sea level (msl) in the western portion of the site to approximately 63 feet above msl in the eastern portion of the site.5 The project site is occupied by existing and vacant industrial uses, surface parking lots, asphalt or concrete storage lots, a roadway, and railroad spur improvements. As discussed in Section 4.2, Biological Resources, unpaved land within the site includes agricultural, annual grassland, landscaped, and ruderal areas. Existing impervious areas cover 40 percent of the project site (10.5 acres, or 457,380 square feet [sf]) and pervious areas covers 60 percent (16.0 acres, or 696,960 sf). Surface Water The project site is within the Lower Alameda Creek sub-watershed, within the larger Alameda Creek watershed. The Alameda Creek watershed drains to Arroyo Mocho, Arroyo de la Laguna, Alameda Creek, with its waters ultimately reaching San Francisco Bay just north of Coyote Hills. At the confluence of Arroyo de la Laguna with Alameda Creek, Alameda Creek begins its descent through Niles Canyon. Lower Alameda Creek is constrained in a flood control channel, a prominent drainage feature known as the Alameda Flood Control Channel. The site is less than 1 mile east of Dry Creek, a tributary to Alameda Creek, which is approximately 1 mile southwest of the project site. Alameda 1 Balance Hydrologics. 2020. Updated Summary of Stormwater Infrastructure Modeling for the Bradford Way Project City of Union City. September 1. 2 CBG Engineers. 2020. Station East – LID Reduction Narrative Memorandum. September 15. 3 Balance Hydrologics. 2020. Additional Hydraulic Modeling of the Existing Zwissig Way Storm Drain Line, City of Union City. October 16. 4 Western Regional Climate Center. 2016. Period of Record, Monthly Climate Summary, Newark, California (046144). Available: https://wrcc.dri.edu/cgi-bin/cliMAIN.pl?ca6144. Accessed: March 3, 2020. 5 ENGEO. 2016. Phase I Environmental Site Assessment – Zwissig Way Parcels, Union City, California. April. Station East Residential/Mixed Use Project November 2020 4.8-1 Draft Environmental Impact Report ICF 00011.19 Environmental Impact Analysis City of Union City Hydrology and Water Quality Creek is largely channelized through Union City and managed by the Alameda County Flood Control and Water Conservation District (Alameda County Flood Control District). Quarry Lakes Regional Recreational Area, which include Rainbow Lake, Horseshoe Lake, Willow Slough, Lago Los Osos, and Shinn Pond, is approximately 1.2 mile south of the project site. There are several storm drains around the perimeter of the project site, including a 21-inch storm drain in Decoto Road, a 27-inch storm drain in 7th Street, and a 42- to 45-inch storm drain in 7th Street. In addition, there are 15- and 18-inch storm drain pipes in Bradford Way and Zwissig Way, respectively. These pipes drain to Line M-3, which, in turn, drains into Line M and then into Alameda Creek. Water Quality The Water Quality Control Plan for the San Francisco Bay Basin (Basin Plan) specifies beneficial uses that apply to water bodies where the potential exists for them to be affected by the project. Dry Creek has water quality requirements for the following beneficial uses: preservation of rare and endangered species, warm freshwater habitat, wildlife habitat, and water contact and non-water contact recreation. Alameda Creek has the same water quality requirements for beneficial uses, with the addition of the following: agricultural supply, groundwater recharge, commercial and sport fishing, cold freshwater habitat, fish migration, and fish spawning.6 Alameda Creek is 303(d) listed as impaired for Diazinon. Diazinon is a pesticide and is addressed in the San Francisco Bay Urban Creeks Diazinon Total Maximum Daily Load Assessment, which was approved by the U.S. Environmental Protection Agency (EPA) in 2007. The Alameda Creek Quarry Ponds also have a history of water quality impairments. However, adequate water quality information is not available for making an appropriate recommendation; therefore, the Quarry Ponds are not 303(d) listed as impaired.7 Groundwater The project site is located in the Santa Clara Valley – Niles Cone Groundwater Subbasin, part of the larger Santa Clara Valley Groundwater Basin, which supplies water to and is managed by the Alameda County Water District (ACWD) with other regional partners. Beneficial uses for the groundwater basin include municipal and domestic water supply, industrial process and service water supply, and agricultural water supply. The Santa Clara Valley Groundwater Basin has a history of groundwater overdraft. The Alameda County Water District diverts impounded water from behind three dams in the Alameda Creek flood control channel to groundwater recharge ponds in the Quarry Lakes Regional Recreation Area in Fremont. This water percolates into aquifers and supplies up to 50 percent of the water used in Fremont, Newark, and Union City.8 Seawater intrusion is common in the basin and has moved landward and into deeper aquifers since first recorded in the 1920s. 6 San Francisco Bay Regional Water Quality Control Board. 2010. Attachment A to the Final Staff Report: San Francisco Bay Basin Water Quality Control Plan, Basin Plan Update, Addition of Water Bodies and Beneficial Uses. Originally published July 7, 2010. 7 State Water Resources Control Board. 2018. 2014/2016 Integrated Report (Clean Water Act Section 303[d] List/305[b] Report)—Statewide. San Francisco Bay Regional Water Quality Control Board. EPA approved: April 6, 2018. Available: https://www.waterboards.ca.gov/water_issues/programs/tmdl/integrated2014_ 2016.shtml. Accessed: March 4, 2020. 8 San Francisco Bay Regional Water Quality Control Board. 2010. Attachment A to the Final Staff Report: San Francisco Bay Basin Water Quality Control Plan, Basin Plan Update, Addition of Water Bodies and Beneficial Uses. Originally published July 7, 2010. Station East Residential/Mixed Use Project November 2020 4.8-2 Draft Environmental Impact Report ICF 00011.19 Environmental Impact Analysis City of Union City Hydrology and Water Quality The Alameda County Water District has begun treating brackish groundwater to allow previously unused groundwater to be used as potable water.9 As discussed in Section 4.7, Hazards and Hazardous Materials, the project site contains residual concentrations of volatile organic compounds (VOCs) in groundwater. Remediation equipment is on portions of the project site, along with numerous groundwater wells. This equipment is associated with remediation of an off-site historic VOC release known as the McKesson release-related plume.10 Flood Hazards The project site is located outside the Federal Emergency Management Agency (FEMA) 100-year floodplain but within FEMA Zone X (unshaded), an area of minimal flood hazard (i.e., above the 500- year flood level). The area immediately north of the project site crosses FEMA Zone X (shaded). This is an area of moderate flood hazard, usually between the limits of the 100-year and 500-year flood or within an area with lesser hazards (e.g., an area with levee protection or a history of only shallow flooding).11 Based on the distance from San Francisco Bay, the project site is not susceptible to tsunami, and there are no reservoirs adjacent to the project site. In addition, San Francisco Bay is a large, open body of water with no immediate risk of seiche. Therefore, the project site is not prone to inundation by tsunami or seiche. 4.8.1.2 Regulatory Setting Federal Clean Water Act Several sections of the Clean Water Act (CWA) pertain to regulating waters of the United States. The CWA is not only the primary federal law for regulating water quality in the United States but also the basis for several State and local laws. Its objective is to reduce or eliminate water pollution in the nation’s rivers, streams, lakes, and coastal waters. The CWA prescribes basic federal laws for regulating discharges of pollutants and sets minimum water quality standards for all waters of the United States. Several mechanisms are used to control domestic, industrial, and agricultural pollution under the CWA. EPA is the overarching authority for protecting the quality of waters of the United States. However, EPA has delegated administration and enforcement of the CWA in California to the State Water Resources Control Board (SWRCB) and the Regional Water Quality Control Boards (RWQCBs). The State has developed a number of water quality laws, rules, and regulations. It also adopts water quality standards to protect beneficial uses of waters of the State, as required by Section 303(d) of the CWA. CWA requirements are addressed through development of a 303(d)/305(b) integrated report, which provides both an update to the 303(d) list and a 305(b) assessment of statewide water quality.