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8.A. - Page 55 <br />Regional Water Quality Control Board for approval. The SPCC Plan would be <br />required to be implemented and would describe prevention measures and response <br />measures for spills of hazardous materials, which would minimize impacts on <br />water quality. Impact 3.7-2 and proposed mitigation are described on Draft EIR <br />pages 3.7-13 and 3.7-14 and Revised Final EIR pages 4-22 and 4-23, which are <br />hereby incorporated by reference. <br />Impact 3.7-4 <br />Impact: Stormwater runoff would likely increase during construction as ground cover is <br />removed, and an increase in impervious surface area in the post -construction <br />period could result in an increase in peak runoff at downstream drainage facilities. <br />These effects could potentially exacerbate downstream drainage, flooding, and <br />erosion problems, creating the potential to result in an increase in peak discharge <br />at downstream drainage facilities, increasing erosion or flooding off site. <br />Mitigation: Mitigation Measure Hydrology -1: Prior to issuance of grading permits or <br />approval of improvement plans, the applicant shall submit a detailed Erosion <br />Control Plan (ECP) to the Director of Public Works of Redwood City for review <br />and approval. The purpose of the ECP shall be to mitigate erosion and <br />sedimentation impacts during the construction period. The applicant shall <br />implement the approved ECP. The detailed ECP shall be accompanied by a <br />written narrative and shall include, at a minimum, the following: <br />a) Proposed schedule of grading activities, monitoring, and infrastructure <br />milestones in chronological format <br />b) Identification of critical areas of high erodibility potential and/or unstable <br />slopes <br />c) Use of soil stabilization techniques such as short-term biodegradable erosion <br />control blankets and hydroseeding. Silt fences shall be installed downslope <br />of all graded slopes. Straw wattles or another appropriate BMP shall be <br />installed in the flow path of graded areas receiving concentrated flows, as <br />well as around storm drain inlets <br />d) Description of erosion control measures on slopes, lots, and streets <br />e) Contour and spot elevations indicating runoff patterns before and after <br />grading <br />fj Filter systems at catch basins (drop inlets) in private streets as a means of <br />sediment control <br />g) Post -construction inspection of all drainage facilities for accumulated <br />sediment, and the clearing of these drainage structures of debris and <br />sediment <br />Mitigation Measure Hydrology -2: Prior to issuance of a grading permit, the <br />applicant shall submit evidence to the City Engineer of Redwood City that <br />coverage under the statewide General Construction Activities Stormwater Permit <br />(General Permit) has been obtained. The applicant shall comply with the NPDES <br />39 <br />