Laserfiche WebLink
• See FEIR, Section 4 . 4 . 3 . <br /> K-3 . Potentially Significant Impact : Runoff and Erosion <br /> [Impact 4 . 4 . 3-3] <br /> The volume and rate of runoff from the Project could <br /> cause excessive erosion and siltation of detention ponds , <br /> creeks , drainage channels , and Old River . <br /> Finding : Changes or alterations have been required in, <br /> or incorporated into, the Project which avoid or <br /> substantially lessen the significant environmental effect <br /> as identified in the FEIR to a non-significant level . <br /> These mitigation measures are listed below. <br /> Statement of Fact : The impact will be reduced by the <br /> following : <br /> • The operating budget of the Community Services <br /> District must be guaranteed to be sufficient for all <br /> maintenance functions necessary to operate the storm <br /> water collection system in order to adequately <br /> mitigate potential erosion and siltation. The budget <br /> should be addressed in the Specific Plan. <br /> • The performance standards and design features of the <br /> inlets to detention ponds must be included in the <br /> Specific Plan. The design must allow for reduction <br /> in the velocity of the incoming water . <br /> • If two-stage detention ponds are used, the inflow <br /> channel for the upper stage (usually dry) must be <br /> constructed to prevent erosion, which may include a <br /> concrete low-flow channel or riprap, and should <br /> terminate at the edge of the lower stage (always <br /> wet) . The design features and performance standards <br /> to prevent erosion must be provided in the Specific <br /> Plan. <br /> • Periodic removal of sediments from detention ponds <br /> must occur to restore the capacities and to minimize <br /> resuspension of sediments . Pond maintenance <br /> objectives, activities, and approximate frequencies <br /> ensuring compliance with this objective must be <br /> described in the Specific Plan; a detailed <br /> description of maintenance activities must be <br /> incorporated into an Operations and Maintenance <br /> Manual for the storm water collection system. <br /> • If grading or construction activities were to occur <br /> during the winter months , local drainage and <br /> C2-24 <br /> 0189r/0202r <br />