2020-065 - Adopting Environmental Findings of Fact

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The Wamer Redhill Mixed -Use Project CEQA Findings of Fact existing conditions. In addition, during construction, vehicles and equipment are prone to tracking soil and/or spoil from work areas to paved roadways, which is another form of erosion that could affect water quality. However, the use of BMPs during construction implemented as part of a SWPPP as required by the NPDES General Construction Permit and included as PPP WQ-1 would serve to ensure that Project impacts related to construction activities resulting in a degradation of water quality would be less than significant. Operation The proposed Project includes operation of retail and restaurant commercial and multi -family residential uses. Potential pollutants associated with the proposed uses include various chemicals from cleaners, pathogens from pet wastes, nutrients from fertilizer, pesticides and sediment from landscaping, trash and debris, and oil and grease from vehicles. If these pollutants discharge into surface waters, it could result in degradation of water quality. As described previously, San Diego Creek Reach] and the Upper Newport Bay, to which the Project site ultimately drains, are currently listed as impaired on the EPA's 303(d) list for various pollutants. However, operation of the proposed Project would be required to comply with the requirements of the Santa Ana Regional MS4 Permit to develop of a project -specific WQMP (included as PPP WQ-2) that would describe implementation of LID infrastructure and non-structural, structural, and source control and treatment control BMPs to protect surface water quality. The Project site is located within the Selenium Concentration Area and the South Basin Groundwater Protection Project area, and is adjacent to the Tustin Marine area, as shown in Draft EIR Figure 5.8-1. Infiltration into the groundwater is prohibited by OCWD within these areas. As such, infiltration of water quality pollutants from the Project would not occur, which would reduce potential impacts to groundwater quality. In addition, the proposed Project would install Modular Wetland System units for water quality treatment, which have been sized to treat runoff from the Design Capture Storm (85th percentile, 24-hour) from the proposed Project. The Modular Wetland System units proposed for the Project consist of biotreatment systems that utilize multi -stage treatment processes including screening media filtration, settling, and biofiltration. The pre-treatment chamber contains a catch basin inlet filter to capture trash, debris, gross solids and sediments, a settling chamber for separating out larger solids, and a media filter cartridge for capturing fine silts, metals, nutrients, and bacteria. Runoff then flows through the wetland chamber where treatment of the water is done through a variety of physical, chemical, and biological processes. As storm water passes down through the planting soil, pollutants are filtered, adsorbed, biodegraded and sequestered by the soil and plants, functioning similar to bioretention systems. The discharge chamber at the end of the unit collects treated flows and discharges it into the existing storm drain in Red Hill Avenue. The WQMP is required to be approved prior to the issuance of a building or grading permit. The Project's WQMP would be reviewed and approved by the City to ensure it complies with the Santa Ana RWQCB MS4 Permit regulations. Overall, implementation of the WQMP pursuant to the existing regulations would ensure that operation of the proposed Project would not violate any water quality standards, waste discharge requirements, or otherwise degrade water quality; and impacts would be less than significant. City of Santa Ana May 2020