SITE INFORMATION AND CORRESPONDENCE

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5.15 WATER RESOURCES TABLE 5.15-9 Pre-development Runoff for the LEC Site Return Period Runoff Peak Runoff Volume Area (years) (cfs) (ft') 4.3 2 1.61 790 4.3 10 2.84 1392 cfs=cubic feet per second ft3=cubic feet TABLE 5.15-10 Post-development Runoff for the LEC Site Return Period Runoff Peak Runoff Volume Area (years) (cfs) (ft3) 4.58 2 4.14 2.30 4.58 10 7.31 3583 The peak runoff for the 2-and 10-year storm events for the site in the pre-and post-development condition was determined and compared. Runoff increased for the post- development condition due to an increase in impermeable surfaces. However,paving will improve both the air and water quality due to the minimization of dust during the dry season and sedimentation of runoff during rain events. 5.15.2 Environmental Analysis Project effects on water resources can be evaluated relative to significance criteria derived from the California Environmental Quality Act (CEQA) Appendix G checklist. Under CEQA, the project is considered to have a potentially significant effect on water resources if it would: • Substantially alter the existing drainage pattern of the site or area,including the alteration of the course of a stream or river,in a manner which will result in substantial erosion or siltation on-or offsite,or in flooding on-or offsite. • Create or contribute runoff water which will exceed the capacity of existing or planned stormwater drainage systems,or provide substantial additional sources of polluted runoff. • Violate any water quality standards or waste discharge requirements,or otherwise substantially degrade water quality. • Substantially deplete groundwater supplies or interfere substantially with groundwater recharge such that there will be a net deficit in aquifer volume or a lowering of the local groundwater table level (e.g.,the production rate of pre-existing nearby wells will drop to a level which will not support existing land uses or planned uses for which permits have been granted). 5.15-18 SAC/3713221082340005(LEC_5.15_WATER_RESOURCES.DOC)