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4. ENVIRONMENTAL ANALYSIS 4.8 HYDROLOGY AND WATER QUALITY pumping tests shall be performed under the temporary and long-term pumping scenarios. The -- aquifer testing shall be completed by a Califomia-certified hydrogeologist with experience with the Sacramento-San Joaquin groundwater system. The test shall be designed,at a minimum,to include a step-drawdown test to determine maximum yield for the well(s)and a constant drawdown test to evaluate the aquifers capacity to sustain acceptable drawdown and to determine yield at the acceptable drawdown. For the purposes of this mitigation, "Acceptable Drawdown" is defined as drawdown that can be maintained without impact to groundwater resources. Results of the test shall be used to develop and refine the groundwater pumping strategy for the mining operation and recommendations for the groundwater pumping strategy, as provided by the certified hydrogeologist, and shall become part of the project. If the pumping tests determine that maintaining the acceptable drawdown provides less yield than required by the project as proposed, and this deficiency can not be overcome by alternating pumping wells,altering groundwater extraction strategies,or alternate plans to reduce water usage,the project applicant shall not commence mining operations until it is demonstrated that the wells proposed for pumping can adequately maintain the necessary supply. Copies of the findings and Cl recommendations of the groundwater well testing shall be submitted to the San Joaquin County Department of Community Deve Qpment. Mitigation Measure 4.8.4b: Multiple Well Pumping Testing Upon completion of the well testing described above in Mitigation 4.8.2a,the project applicant shall complete a multiple well aquifer testing program which involves pumping a groundwater well over an extended period of time and observing results in an array of monitoring wells. The test would provide necessary data to evaluate the groundwater pumping and drawdown effects on local and regional groundwater wells. The pumping tests shall be performed under the temporary and long-term pumping scenarios. A California-certified hydrogeologist with experience in the _ San Joaquin-Sacramento area should develop and conduct this testing program. The aquifer test shall include water level measurements from at least three monitoring wells installed within the project boundaries at a depth that intersects the source aquifer. In addition,monitoring shall be conducted in offsite wells to evaluate regional effects. The managing California-certified hydrogeologist would determine appropriate offsite monitoring well locations. Results of the test shall be used to develop and refine the final groundwater extraction plan for the mining operation and recommendations provided by this study, as provided by the certified hydrogeologist, shall become part of the project. If the tests determine that the aquifer can not accommodate the pumping rate proposed by the project without resulting in unacceptable drawdown in local or regional wells,the project applicant shall not implement aspects of the project that would require water from a groundwater source. For the purposes of this mitigation measure,"unacceptable drawdown'is defined as drawdown that would permanently cause a decline in a nearby groundwater well such that groundwater levels in that well are decline below pumping levels and extraction is no longer possible. Copies of the findings and recommendations of the groundwater well testing shall be submitted to the San Joaquin County Department of Community DevelpmenY� � , J RMC Pacific Vem bs Quarry Mining and Reclamation Project 4.8-30 ESA/203015 Administrative Draft EIR March 2004