AgdaPkt 2017-01-09 Closed and Joint

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TA. - Page 74 Documentation: a. & e. The proposed project site is located within a downtown urban setting, which is served by an existing storm drain system that outfalls into San Francisco Bay. Implementation of the proposed project would utilize the existing storm water conveyance facilities in Bradford Street, and would not contain uses that involve the discharge of cooled/heated water or pollutant -laden runoff. However, given the local urbanized area, the existing storm water flows contain urban runoff with contaminants such as oil, grease, particulates, metals, and solvents. Because the proposed project is subject to the requirements of a National Pollutant Discharge Elimination System (NPDES) permit for municipal storm water runoff and other requirements of the City, County, and Regional Water Quality Control Board, the conditions of which limit the volume of contaminants allowed to enter the storm drain system, the proposed project would not violate any water quality standards or waste discharge requirements. Furthermore, the DTPP program EIR (pp. 10-23 through 10-25) concluded that DTPP facilitated development would not result in any significant water quality or storm water drainage impacts. The proposed project is in compliance with all applicable DTPP standards, and as a result, water quality and storm water drainage would be less than significant. The City's Drainage Guidelines for Commercial Development require post -development storm water discharge to be equal to or less than pre -development discharge. Also, the City mandates that proposed site conditions maintain the same runoff for the 30 year storm event as compared to the existing 10 year event. Storm water runoff collected on the project site currently drains, and would continue to drain, to the City storm water system (Preliminary Engineering Study, 603 Jefferson Avenue, Redwood City, California 94603; BKF Engineers; October 26, 2015, pp. 6 and 7; Plan Sheets C8.00 and C9.00, 3125116). A standard City condition of project approval requires that storm water treatment controls be designed and sized to treat runoff from the entire project site using flow- or volume - based sizing criteria specified in Provision C.3.d of the Municipal Regional Stormwater Permit. Based on these requirements, the project's drainage plan (Plan Sheet C9.00, 3/25116) identifies two drainage concepts for identified Drainage Areas #1 and #2: (1) an on-site, underground detention vault with media filter near Bradford, which would retain and treat 72 percent of the site drainage area (16,134 square feet) before the storm water enters the City system; and (2) raised planters that would serve as a bioretention area on the second floor outdoor terraces, and would retain and naturally filter the other 28 percent of the site drainage area (6,400 square feet) before the storm water enters the City system. All design of biotreatment measures is consistent with technical guidance for the applicable type of biotreatment measure provided in Chapter 6 of the C.3 Technical Guidance. Plan Sheets C8.00 and C9.00, 3125116, and Plan Sheets L1.0, and L1.2, 3114/16, illustrate and summarize the drainage plans and calculations per City criteria, and identify the proposed locations and details of the media filter vault and bioretention areas. The project -specific preliminary engineering study provides further details (BKF Engineers, October 26, 2015). The project is expected to qualify for a 75 percent exemption under Special Project Category "C" of the San Mateo Countywide Water Pollution Prevention Program. This means that the project would be 75 percent exempt (in storm drainage volume) from County low impact development (LID) requirements because the project: (1) is within '/- mile of a transit hub (Caltrain-Sam Trans) (25 percent exempt); (2) would have no surface parking (20 percent reduction); and (3) would have a floor area ratio (FAR) of 4:1 (30 percent reduction). (BKF Engineers, October 26, 2015, p. 6 and C.3 Narrative) The result would be that up to 75 percent of the project site's impervious surface runoff could be treated with media filter devices approved by the Bay Area Stormwater Management Agencies Association (BASMAA). As described above, the project plans meet this threshold, by having no more than 75 percent of the site drainage treated by a detention vault with media filter. This proposed exemption is subject to City review and approval. All storm water data and components provided by the project applicant are subject to review, approval, and on-site inspection by the City. The project would be subject to these standard requirements as conditions of project approval. As a result of DTPP standards and the City requirements described above, the proposed project would not generate additional storm water drainage impacts beyond those analyzed in the DTPP program EIR. b. The City of Redwood City does not rely on groundwater as a water supply source. Implementation of the proposed project would not require substantial amounts of water such that it would result in substantially depleted groundwater supplies (see item XVII[d] [water supply] of this checklist). Therefore, the proposed project would not 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. Furthermore, the DTPP program EIR (p. 10-25) concluded that DTPP facilitated development would not result in any significant groundwater impacts. The proposed project is in compliance with all applicable DTPP standards, and as a result, groundwater impacts would be less than significant. c. & d. The proposed project would neither change the amount of surface water nor change the currents, course, or direction of water movements in any surface water body. As a result, project implementation would not substantially alter the existing drainage pattern of the project site or DTPP area. Furthermore, the proposed site does not contain 044