Laserfiche WebLink
Eouuno G.exawn Jx. <br /> 3-i. xxon <br /> MV M RODAMUEL <br /> Water Boards <br /> Central Valley Regional Water Quality Control Board <br /> 8 September 2014 <br /> Stephen Salvatore, City Manager <br /> City of Lathrop <br /> 390 Towne Center Drive <br /> Lathrop, CA 95330 <br /> APPROVAL OF GROUNDWATER MONITORING WELL ABANDONMENT AND <br /> INSTALLATION WORKPLAN, CITY OF LATHROP CROSSROADS WASTEWATER <br /> TREATMENT FACILITY, SAN JOAQUIN COUNTY <br /> Central Valley Regional Water Quality Control Board staff has reviewed the 27 August 2014 <br /> Groundwater Monitoring Well Abandonment and Installation Workplan for City of Lathrop <br /> Crossroads Wastewater Treatment Facility. <br /> In the Workplan, the City proposes to: <br /> 1) Abandon KMW-7, which is a downgradient well located in Land Application Area 2 <br /> (LAA2). The City has concluded that this well likely has well construction problems <br /> based on monitoring data (higher pH and groundwater elevations). The Workplan states <br /> that the pH in samples from KMW-7 has consistently been outside the typical range of <br /> the pH values from other Crossroads WWTF and MBR WRP-1 monitoring wells, and <br /> that indicates the presence of cement grout in or near the well screen and may influence <br /> the water chemistry of samples from the well. The Workplan also states that <br /> groundwater beneath LAA2 is currently monitored by two wells, KMW-3 and KMW-7, <br /> and therefore the data from KMW-7 is redundant. Therefore, the City recommends the <br /> destruction and removal of KMW-7 from the Crossroads Wastewater Treatment Facility <br /> groundwater monitoring network. <br /> 2) Abandon four piezometers located in LAA 3 before LAA3 is converted to percolation <br /> ponds. <br /> 3) Install an upgradient well KMW-9 located west of the LAA3. The City of Lathrop has <br /> proposed to convert LAA3 into percolation ponds, which will likely cause localized . <br /> groundwater mounding and impact existing up-gradient well KMW6 (future compliance <br /> well). Therefore, a new upgradient well KMW-9 is necessary. <br /> 4) Install a downgradient well KMW-8 at immediately outside of the LAA3 northwest <br /> boundary. <br /> KARL E. LONCLEY SCD, P.E.,CHAIR I PAMELA C. CREEDON P.E., BCEE, EXECUTIVE OFFICER <br /> 11020 Sun Center Drive#200,Rancho Cordova.CA SE670 I www.waterboards.ca.gov/contralvalley <br /> ��gECY°L!°PPlfl <br />