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5.Alternatives suspected that additional high quality aggregate material exists below the existing groundwater — level and could be extracted with dewatering techniques or a"wet' mining operation. The option has the potential to reduce the extent of the footprint of the mine. Basis for Selection The San Joaquin County Title, Section 9-1415.3(u) requires an impact evaluation for quarry — excavations below the groundwater level of the uppermost aquifer. Should additional resources exist below the groundwater level, the extraction of them may be a more environmentally sensitive alternative than disturbing additional land elsewhere for a like resource. 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. 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." Further, SMARA holds the intent of the Legislature whereby "the production and conservation of minerals are encouraged, while giving consideration to values relating to recreation,watershed, wildlife, range and forage and aesthetic enjoyment." 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. Distinctive Environmental Characteristics The following summarizes potential impacts of the"Extraction of Aggregate Below the Groundwater Level"alternative: 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. 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 RMC Pacific Vernalis Quarry Mining and Reclamation Project 54 ESA 1203015 Draft Environmental Impact Report May 2006