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5.ENVIRONMENTAL CHECKLIST MOUNTAIN HOUSE NEIGHBORHOODS K AND L INITIAL STUDY 8.HYDROLOGY AND WATER QUALITY Lake Features Development of Neighborhoods K and L would include permanent lake features (47,33 acres in Neighborhood K and 52.93 acres in Neighborhood L)to be used for flood protection,water quality enhancement, and recreational purposes. The lake features would be similar to the golf course water features in Neighborhoods I and J. The permanent lake features in Neighborhoods K and L would discharge to Mountain House Creek. The lakes would be surrounded primarily by low-density residential land uses and would include some lakefront properties. The lakes would provide sufficient storm water storage to allow for the 100-year flood event to be stored in the lakes without overtopping. Water Quality Basin(WQB) No. 1 WQB No. 1 is an existing 13-acre water quality/detention basin located at the southern corner of Neighborhood L. WQB No. 1 captures and treats"urban" runoff from existing Neighborhoods B, D,and F. The runoff is stored for a minimum of 24 hours before being discharged by gravity to Mountain House Creek. Flood Protection at Old River Engineered fill would be used to raise all building pads above the 100-year FEMA flood hazard zone.The FEMA-designated 100-year base flood elevation is 10.4 feet above msl. In 2007, the State of California passed Senate Bill 5,which requires 200-year flood protection for urban or urbanizing areas. Preliminary maps released by the DWR indicate that portions of Neighborhoods K and L are within the 200-year floodplain. While the state has not yet determined the official 200-year floodplain elevation,flood protection for those portions of Neighborhoods K and L located within the 200-year flood elevation would be provided in the same manner in which 100-year flood protection would be provided, by raising the ground surface elevation through the placement of engineered fill. Recent Changes Regarding Use of Reclaimed Water for Irrigation The Master Plan required the evaluation of using reclaimed secondary and/or tertiary water for on-site and/or off-site landscape and/or agricultural irrigation. Since preparation of the Master Plan, a permit has been obtained from the Regional Water Quality Control Board (RWQCB) and a discharge pipeline has been constructed to convey treated effluent from the wastewater treatment plant to Old River, thereby eliminating the need to identify suitable locations for application of treated effluent. As a result,the use of reclaimed water for landscape irrigation is no longer proposed as part of the Neighborhoods K and L development project, ism++I 5-108