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EDMUND G. BROWN JR. <br /> �j�;o GOVERNOR <br /> C A L ITT P O W M 1 M SEC RET' ARY FOR <br /> EW DRIOUE2 <br /> WaterBoards ENVIRONMENTAL PROTECTION <br /> Central Valley Regional Water Quality Control Board RECEIVED <br /> JUN 2014 <br /> EWRONM4 June 2014 <br /> E TAI.HLT <br /> Erin Fanning — Environmental Manager PERMITISERVICES <br /> 9999 S. Austin Road <br /> Manteca, CA 95336 <br /> UNSATURATED ZONE MONITORING SYSTEM REVIEW, FORWARD LANDFILL, <br /> SANJOAQU/N COUNTY <br /> Central Valley Regional Water Quality Control Board staff reviewed the Unsaturated Zone <br /> Monitoring System Review report submitted 20 May 2014. The report found that seven of your <br /> suction lysimeters have been damaged or destroyed, two suction lysimeters do not hold a <br /> vacuum so that they do not perform as monitoring points and eight pan lysimeters have <br /> restricted access ports that prevent routine monitoring. The report concludes that four of the <br /> damaged suction lysimeters (LY-E1A, LY-E1 B, LY-E2A & LY-E213) can be functionally replaced <br /> with two new suction lysimeters; three suction lysimeters (FU-03, WMU D-01 N &WMU D-02) <br /> can be functionally replaced by adjacent pan lysimeters; and two suction lysimeters (E-1 & D- <br /> 93B) can be functionally replaced by continued monitoring of adjacent (either deeper or <br /> shallower) existing suction lysimeters. The report also recommends installation of access ports <br /> in four of the eight pan lysimeters. <br /> In the Central Valley, because of soil conditions and generally low soil moisture content, suction <br /> lysimeters do not perform well, however pan lysimeters are reliable. Therefore, open access <br /> ports must be installed in all existing and future pan lysimeters, and where available, pan <br /> lysimeters should be monitored in preference to the less reliable suction lysimeters. Also, there <br /> is no need to replace suction lysimeters FU-03, WMU-01 N and WMU D-02 with new suction <br /> lysimeters, the monitoring requirement is covered by the adjacent pan lysimeters. Staff concurs <br /> with the plan to replace the two lysimeter pairs (LY-E 1 A/LY-E 1 B and LY-E2A/LY-E2B) with new <br /> single lysimeters (one replacement for each pair). Non-performing suction lysimeters (E-1 and <br /> D-93B) with no adjacent pan lysimeters should be replaced. Regular monitoring should <br /> continue at the background lysimeter LY-BG1. <br /> If you have any questions, please call me at (916) 464-4614 or via email at <br /> rocs.atkinson@waterboards.ca.gov. <br /> Ross D Atkinson <br /> Engineering Geologist <br /> Title 27 Permitting and Mines Unit <br /> cc list: See next page <br /> KARL E. LONGLEY SCD, P.E., CHAIR I PAMELA C. CREEDON P.E., BCEE, EXECUTIVE OFFICER <br /> 11020 Sun Center Drive#200,Rancho Cordova,CA 95670 1 www.waterboards.ca.gov/centraIva]ley <br /> C'V RECYCLED PAPER <br />