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1 KOPPEL-STOCKTON TERMINAL <br /> Monitoring Well Installation Work Plan <br /> 1 <br /> 1 The Koppel Stockton Terminal(Koppel) is a former dry fertilizer warehouse. The site is <br /> located in Stockton west of Ventura Avenue,between the extensions of Hazelton Avenue <br /> and Sonora Street,approximately 1 mile west-southwest of the I-5/Highway 4 interchange, <br /> 1 next to the Port of Stockton,California. The site layout of the Koppel Stockton Terminal is <br /> presented on Figure 1. <br /> ' Phytoremediation is being used to remove nitrogen from soil and groundwater at the site. A <br /> test grove of 267 poplar trees was planted on approximately one acre on the southern end of <br /> the site in May 1998 to evaluate the effectiveness of phytoremediation.An additional 1,250 <br /> ' hybrid poplar trees and 230 willow trees were planted in the vicinity of the turnaround area, <br /> stormwater pond,former bagging plant,and in the area north of the warehouse during <br /> March through June 2000. <br /> 1 At the request of the Regional Water Quality Control Board (RWQCB) (RWQCB 2004), <br /> CH2M HILL is submitting this Monitoring Well Installation Work Plan for the installation of <br /> one monitoring well (KP-10S)north of the site. This report includes the following <br /> 1 information: <br /> • Rationale for well installation <br /> ' • Description of well drilling procedures <br /> • Description of well construction and development <br /> • Schedule for installation and sampling <br /> 1 1.0 Rationale for Well Installation <br /> Twelve 4-inch-diameter monitoring wells and five 2-inch-diameter piezometers have been <br /> 1 installed at Koppel between 1996 and 2000 (CH2M HILL, 1996;CH2M HILL, 1998; <br /> CH2M HILL HILL,1999;CH2M HILL,2000).Water quality data have been obtained from <br /> these monitoring wells and piezometers quarterly between 1996 and 2000 and semi- <br /> annually between 2000 and 2004. As a result of the sampling,data trends have been <br /> established for most wells onsite.Data trends show reductions in nitrate concentrations in <br /> shallow groundwater in the vicinity of the original poplar test grove area. In addition, <br /> 1 nitrate concentrations downgradient of the original poplar test grove are relatively low, <br /> indicating that natural attenuation is occurring. <br /> 1 The former Cal Farm Supply facility is located north of the Koppel Stockton Terminal <br /> (see Figure 1).Nitrate-nitrogen concentrations in groundwater collected between 1997 and <br /> 1 1999 from Cal Farm Supply's southernmost monitoring well,MW-6,ranged between 216 <br /> and 367 milligrams per liter (Karsyn,2004).These concentrations are closer in magnitude to <br /> Koppel's proximate well,KP-2 (see Figure 1),than nitrate concentrations detected in other <br /> 1 <br /> RDDA:\CHEVRONM0184\REPORTS@OD4_MONRORINGWELLWP12004-MWELLWP.DOC 1 <br /> 1 <br />