SU0008578 - Laserfiche WebLink

Home Browse Search

5.ENVIRONMENTAL CHECKLIST MOUNTAIN HOUSE NEIGHBORHOODS KAND L INITIAL STUDY 8.HYDROLOGY AND WATER QUALITY that describes maintenance activities that would be necessary for continued effectiveness of basins(Policy 15.6a). The 1994 MEIR recommends that potential project impacts associated with shallow groundwater levels be mitigated through the preparation of a Preliminary Soils Report(i.e., Geotechnical Engineering Report)for each subdivision to determine seasonal groundwater levels and provide appropriate design recommendations(Section 6.8.3). At the time of this Initial Study, geotechnical engineering reports for Neighborhoods K and L had been completed. Discussion Regarding Neighborhoods K and L a) Would the project violate any water quality standards or waste discharge requirements? Project implementation could potentially affect water quality if project construction activities adversely affected the water quality of downstream water bodies as a result of increased soil erosion and/or the accidental release of construction-related chemicals into site runoff; resulted in the degradation of water quality from construction dewatering discharges; or resulted in a long-term increase in pollutant levels in storm water originating from Neighborhoods K and L. Degradation of Water Quality During Construction Activities. During project construction, grading and earthwork would result in the removal of established groundcover that serves to stabilize site soils, and the exposure of soils to the erosional forces of rainfall and runoff,thereby potentially resulting in increased sediment load in downstream waters. Construction activities at the Neighbor- hoods K and L project site could also result in the accidental release of hazardous waste products such as adhesives,solvents, paints, and petroleum products that, if not managed properly, could adhere to soil particles, become mobilized by rain or runoff, and degrade water quality. Construction dewatering in excavations also has the ability to adversely affect downstream water quality if the dewatering effluent is contaminated or if the rate of the effluent discharge is R erosive. In the absence of proper controls, construction activities could affect �7 water quality in downstream water bodies, including Mountain House Creek and Old River. Project construction activities would be subject to the National Pollutant Discharge Elimination System(NPDES)construction general permit requirements described below. Mandatory adherence to NPDES permit requirements would ensure that impacts on water quality during construction would be less than significant. Thecomjroect would be required to IY with the NPDES General Permit for P q P Storm Water Discharges Associated with Construction and Land Disturbance Activities(construction general permit,Order No.2009-0009). Effective on July 1, 2010, Order No.2009-0009 applies to construction sites that include one or more acres of soil disturbance.Construction activities include clearing,grading, �srrm) 5-110