SITE INFORMATION AND CORRESPONDENCE

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5.15 WATER RESOURCES • Vertical hydraulic gradients will be estimated annually using the existing shallow groundwater monitoring wells. • A sampling port will be installed at the well and the well will be sampled for general chemistry parameters,nitrates, and coliform, at least annually. Given the low production rate of the onsite well relative to what the aquifer is capable of producing,the effect on local groundwater levels is expected to be negligible. An extensive monitoring well network exists for several miles surrounding the WPCF,which allows actual water level and water quality effects to be observed,if they are measurable. Operation of this well is not expected to have any measurable effect on production wells or surface water bodies within 0.5 mile of the LEC potable well or contribute to the migration of groundwater contaminants. A Technical Memo evaluating the potential groundwater impacts associated with the LEC potable supply well was prepared by a professional geologist and is included in Appendix 5.15B. Groundwater is available within the Eastern San Joaquin Subbasin to supply the LEC. In the vicinity of the LEC project site, groundwater recharge and water-use returns exceed the current and expected future pumping,which occurs primarily for agricultural use. Sources of recharge in the vicinity of the LEC include irrigation of Delta lands and seepage from related waterways to the west,surface-water-irrigated lands to the north and east, percolation from WPCF storage ponds, and recharge from WPCF land application areas (City of Lodi,2006). Because the LEC project would not substantially deplete groundwater supplies such that there would be a net deficit in aquifer volume or a lowering of the local groundwater table level,impacts to groundwater are less than significant. As described above, groundwater recharge in the vicinity of the LEC occurs from several sources. Once developed,the project would result in 4.4 acres of impervious surfaces,which will not interfere substantially with groundwater recharge and impacts are less than significant. Because the project will use only a small amount of water,the project is unlikely to affect groundwater quality. No changes in the existing physical or chemical conditions of groundwater resources are expected as a result of the LEC project and no impacts to groundwater quality would occur. 5.15.2.2.5 Flooding Potential The LEC project site is in the 100-year flood plain (Zone A) as defined by FEMA. The potential for a 100-year flood event to impact the site is medium to high. The LEC project site is on the eastern edge of the Delta and is protected from the Delta by a system of levees. Weakness and instability within the Delta levee system has led to the creation of numerous programs targeted at repairing and maintaining the Delta levees. The City of Lodi Municipal Code,Title 15 (Buildings and Construction) addresses flood damage prevention (Chapter 15.60) and sets guidelines for development in flood hazard areas. A development permit shall be obtained before construction or development begins within any area of special flood hazards (Section 15.60.070 of the Lodi Municipal Code). Furthermore, all construction and development in flood hazard areas must adhere to the Standards of Construction in Section 16.60.140,Article III,Provisions for Flood Hazard Reduction. While the project could potentially expose people or structures to significant risk of loss,injury, or death resulting from levee failure,compliance with the Lodi Municipal Code would sufficiently mitigate any flood risk to a less-than-significant level. Furthermore,the LEC 5.15-22 SAC/3713221082340005(LEC_5.15_WATER_RESOURCES.DOC)