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Drains a and Floodin x The alternative site has relatively mild slopes of about 0. 5%. The elevations range from approximately 45 feet in the east to 40 feet in the west. There are no major drainage facilities on this site. Under existing conditions, storm water runoff either percolates into the soil or flows to the southwest. The project as proposed would utilize on-site retention ponds to accommodate storm runoff. The Final EIR concluded that the close proximity of the standing water in the retention ponds to water wells increases the potential for contamination of the well supply with surface water. Furthermore, retaining storm water on site has the potential for raising the groundwater level during the winter months. If seepage pits are utilized due to on-site soil constraints, this situation could render them less effective. These conclusions would also apply to development of the alternative site due to similar on-site soil conditions. To offset the potential health-related hazards associated with the use of individual retention basins the FEIR recommends that: 1) individual lot sizes be increased in size to at least 2 acres to allow maximum physical setback between facilities; or, 2) that a public drainage system be installed utilizing terminal drainage (see pages 47 and 48) . These mitigations would apply to development of the alternative site. As stated in the FEIR (see page 45) , the proposed project site is located outside the 100-year flood zone and has been determined by the Federal Emergency Management Agency (FEMA) to be in an area of "minimal flooding. " The alternative site, however, is located in the 100-year flood zone as defined by FEMA and as shown on Figure 8. Lower Mosher Creek is located approximately one mile north of the alternative site and drains approximately 10 square miles at Highway 99. As shown in Figure 8, the areas north of the proposed project site, including the alternative site, would be susceptible to 100-year flooding from Lower Mosher Creek overflowing its banks. ; t Due to the potential flood hazard, development of the alternative site would require installation of flood control and drainage facilities, or other improvements sufficient to y provide all building sites within the subdivision with 100-year flood protection. County Flood Ordinance requires that the floor level of all residential construction be elevated to 1' above the flood elevation. Flood protection features would not be required for the proposed project site as it is outside of the 100-year flood zone and is not subject to potential flood hazard. Water Su 1 alit Potable water service in the Morada Area is provided by water wells. Many lots have individual wells, however, there are several small subdivisions with community water supply systems. The proposed project would utilize individual wells. 30