SITE INFORMATION AND CORRESPONDENCE

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5.15 WATER RESOURCES • Place within a 100-year flood hazard area structures that will impede or redirect flood flows. • Cause inundation by seiche,tsunami, or mudflow. 5.15.2.1 Construction Impacts 5.15.2.1.1 Drainage The general site grading will establish a working surface for construction and plant operating areas,and will provide positive drainage from buildings and structures, as well as adequate ground coverage for subsurface utilities. During construction,approximately 4.4 acres of land associated with the LEC project will be graded. There are four proposed LEC project laydown and/or parking areas (A through D),that are to the east and northeast of the proposed LEC site (Figure 1.1-3). Surface water impacts are anticipated to be related primarily to short-term construction activity and would consist of increased turbidity due to erosion of newly excavated or placed soils. However,compliance with engineering and construction specifications, and following approved grading and drainage plans will effectively mitigate these short-term impacts. Furthermore, as required under the General Permit for Stormwater Discharges Associated with Construction Activity (SWRCB Water Quality Order No. 99-08-DWQ; SWRCB, 1999), a Storm Water Pollution Prevention Plan(SWPPP)will be prepared for the construction site and will include best management practices (BMPs)for erosion and sediment control. The SWPPP will be prepared prior to construction of the LEC project to prevent the offsite migration of sediment and other pollutants, and to reduce the effects of runoff from the construction site to offsite areas.Successful implementation of the SWPPP will ensure that construction impacts to drainage are mitigated to a less-than-significant level. 5.15.2.1.2 Water Quality Potential water quality impacts due to construction include impacts to surface water runoff during excavation and construction. In addition,construction materials could contaminate runoff or groundwater if not properly stored and used. Such construction impacts will be less than significant with implementation of a SWPPP and associated BMPs,including practicing proper housekeeping at the construction site. A SWPPP is required under the General Permit for Stormwater Discharges Associated with Construction Activity (SWRCB Water Quality Order No. 99-08-DWQ;SWRCB, 1999) for projects resulting in one or more acres of soil disturbance. SWPPP procedures include submitting a Notice of Intent (NOI) to the Central Valley Regional Water and Quality Control Board (RWQCB) and developing the SWPPP prior to the start of construction activities. Implementation of the SWPPP will prevent the offsite migration of sediment and other pollutants,and will reduce the effects of runoff from the construction site to offsite areas,thereby reducing construction impacts to water quality to a less-than-significant level. Water used for dust control and soil compaction during construction will not result in discharge because only a minimal amount of water will be used for this purpose. Therefore, no impact to water quality would occur as a result of dust control and soil compaction during construction. During the construction period,sanitary waste will be collected in portable toilets supplied by a licensed contractor for collection and disposal at an SAC1371322/082340005(LEC_5.15_WATER_RESOURCES.DOC) 5.15-19