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sensitive alternative than disturbing additional land elsewhere for a like resource. (Draft EIR, p. 5-4.) The California Division of Mines and Geology(CDMG) (now known as the California Geological Survey) has classified(14 CCR Section 3550.14) sectors containing Portland Cement Concrete (PCC) aggregate"an indispensable,high grade construction aggregate" in the project area including portions of the project site. The State Mining and Geology Board, upon the classification of this resource,has recognized,through their designation process, that these resources are regionally significant. (Draft EIR, p. 5-4.) The classification and designation of these resources is consistent with the Surface Mining and Reclamation Act (SMARA)of 1975 whereby the State Legislature found that"extraction of minerals is essential to the continued economic well-being of the State and the needs of the society." (Draft EIR,p. 5-4.) SMARA requires that all reclamation plans include"an assessment of the effect of implementation of the reclamation plan on future mining in the area."The San Joaquin County Development Title, Chapter 9-1415 recognizes SMARA and states that all approved Quarry Extraction Permits are subject to SMARA. (Draft EIR,p. 5-4.) Agricultural and domestic groundwater users extract groundwater from the upper unconfined aquifer for their primary source of water or to supplement surface water supplies. Although it has lower water quality, the upper, unconfined zone is a beneficial use aquifer and is an important water resource. (Draft EIR,p. 5-4.) Large mining operations that intersect or extend below groundwater levels cause groundwater to seep into the excavation and will rise to the approximate level of the surrounding groundwater. The influx of groundwater inundates the bottom of the mining excavation. Once the groundwater becomes surface water within the excavation, it is available for evaporation. Large surface areas and hot temperatures can accelerate evaporation rate and increase evaporation losses. If groundwater seeps into an excavation and is then evaporated, it can constitute a loss to the groundwater supply. These rates are relatively small compared to groundwater pumping but, in some cases, can represent a measurable groundwater loss. Groundwater seepage into a large excavation can also alter groundwater flow direction and flow gradients within the aquifer which thereby alters natural groundwater flow. (Draft EIR, p. 5-4.) Groundwater seepage and inundation within the active mining phase could cause a groundwater quality issue as surface water and pollutants from the surface commingle with the incoming groundwater. The degradation would be localized in areas where surface pollutants are present and are allowed to enter the water. The amount of unpolluted surface and groundwater would likely be sufficient to dilute pollutant loads to below regulatory action levels. (Draft EIR, p. 5-5.) With a deeper excavation below the groundwater level, the temporary and permanent slopes would be higher, thereby increasing the potential for slope instability. A portion of the slopes would be saturated,potentially increasing safety issues. The geologic material, its structure and attitude, and amount of groundwater can affect the potential for slope failure. Slope stability and the potential for slope failure would be increased with this alternative. (Draft EIR,p. 5-5.) 42