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" •, 60—.0 G.8ao,vn JR, oovear:oa fiFCaE.!ARY R P Water DalQVFZ ater Boards ....MORMPWTAt PACTf..TIOW Central Valley Regional Water Quality Control Board 18 September 2014 F. Wally Sandelin Public Works Director City of Lodi 1331 South Ham Lane Lodi, California 95241 MONITORING WELL INSTALLATION WORKPLAN APPROVAL, CITY OF LODI WHITE SLOUGH WATER POLLUTION CONTROL FACILITY, SAN JOAQUIN COUNTY I have reviewed the Monitoring Well Installation Work Plan (Work Plan), which was prepared by West Yost Associates on behalf of the City of Lodi (City) and submitted by the City on 3 September 2014. The workplan proposes the installation of a shallow monitoring well at the White Slough Water Pollution Control Facility (WPCF), which is owned and operated by the City. The WPCF provides tertiary treatment of municipal wastewater under Waste Discharge Requirements (WDRs) Order R5-2007-0113-01. The Work Plan was submitted in accordance with Section VI.A.1 of the Monitoring and Reporting Program for the WDRs, which requires the submittal of plans and specifications for the construction and/or sampling of any additional groundwater monitoring wells at the facility. Groundwater monitoring well WSM-2 is located southwest of two wastewater equalization ponds at the WPCF. The City has come to suspect that the well may have been damaged during construction of tertiary improvements to the WPCF, which were completed in January 2009. Since that time, nitrate-nitrogen concentrations in groundwater have fluctuated inconsistently, as compared with previous monitoring data collected from the well since 1989. As a result, the City proposes to install and sample a nearby groundwater monitoring well (WSM-2R)to evaluate the continued reliability of WSM-2 and decide whether WSM-2 should be abandoned. Based on my review of the groundwater monitoring data for WSM-2 presented in the Work Plan, I concur with the City's suspicion that the integrity of monitoring well WSM-2 may have been compromised as a result of nearby construction activities. The workplan is consistent with the requirements of Order R5-2007-0113-01 and is hereby approved. Monitoring well installation, sealing and grouting procedures must follow San Joaquin County Environmental Health Department permitting guidelines and effectively seal the shallow groundwater interval from deeper water-bearing zones. The Work Plan states that the City intends to install and begin monitoring of WSM-2R such that three months of groundwater monitoring data from the well can be included in a Best Practicable Treatment or Control (BPTC) Study, which is required to be submitted by 1 February 2015, pursuant to Provision VI.C.5.a of the WDRs. WSM-2R shall be incorporated into the monitoring well network and monitored in accordance with R5-2007-0113-01. KARL E. LoNGIEY SoD, P.E.,CHAIR I PAMELA C.CREeooN P.E.,BCEE,exeouttve orrtcm ................. ........ ......... 11020 Sun Center Drive#200.Rancho Cordova.CA 98870 1 www.waterboards.ca.gov/centralvatfey .. c—m-