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L U H D_ O 9 F F Q S CA L M A N I N I GROUND-WATER RESOURCES ' y ' C' 0-N S LJ L T I N G ENGIINFFRS HYOnOLOGY •'01mVELOPMENT • MANAGEMENT February 9,2009 LSCE File 08-1-_092. FES 1,0 �t9 Mike Huggins _Sari Joaquin County Environmental Health Department 600 E. Main Street Stockton,CA 95202-3029 SUBJECT: GROUNDWATER MONITORING PLAN ' FOR GRANITE'S VERNALIS PLANT,'SAN JOAQUIN COUNTY, CA Dear Mr.Huggins: I On behalf of Granite Construction Company(Granite),Luhdorff and Scalmanini,Consulting Engineers (LSCS)has prepared this Groundwater Monitoring Plan(GMP)for Granite's Vernalis Aggregate Mining Plant(Plant)located at 37400 South Bird Road,Tracy,CA-95304.(Figure 1). Granite is operating the Plant in accordance with its Revised Conditional Use Permit for Quarry Excavation and Excavation Plan No. QX-94-1 issued by San Joaquin County Community Development Department on February 9,2005 (San Joaquin County,2005). This GMP was prepared to comply with Item 3d of the Conditional Use Permit. Item 3d states: E "A groundwater monitoring plan is to be submittteelto the Eyr ironmental Health Division for review an(d)approval. The plan needs to address overdraft,flow patterns,and possible changes in . groundwater_quality. Environmental Health will charge for review and permitting as deemed necessary.'.' The Plant is located in the southwest part of San Joaquin County bounded by Bird Road to the west, Teichert Aggregates. Vernalis mining site to the north, and Interstates 5 and 580 to the east and southwest,respectively. The Plant is situated on the alluvial fans and plains of the western portion of . the San Joaquin Valley immediately northeast of the Coast Range foothills (Figure 2). The land surface on and surrounding the project site slopes to the northeast. Granite is permitted�o-§eq'qentially extract aggregate (sand and gravel)from 380 ares ofth 501-acre site over a period o 30 years. Mining pits will be excavated to a maximum�dptlfof 150 feet�`belcaw ground surface(bgs)-and end approximately 12 feet above the highest recorded groundwater level. Production is approved for 2,000,000 tons per year(2 MTY), with processing activities consisting of crushing,washing, sizing, and sorting of sand and gravel resources. Upon reaching the target depth, operations will commence with the excavation of a new pit,utilizing the spent pit for wash water fines storage. The Plant utilizes recycled water from the settling/recycling.p_oAd to wash the aggregate, and that wash — water is discharged back to the pond. -A'small portion of the water is consumptively used in this process through evaporation or as product moisture that remains coated on the sold aggregate. The consumptive use also incltl-es wash waterTost via pon'c infiltration(although infiltrated pond water is returned to groundwater)and is replaced by pumping groundwater. The consumptive use of water at the Plant was estimated to average 1,195 acre-feet per year between 2006 and 2035 (Granite, 2006). SOC First SureeL Wcodlard, CA S58S5-4026 530661.0109 Fax 530.661.680S