Laserfiche WebLink
f <br /> h y <br /> } t t <br /> {I � <br /> ' REG 603 UPDATE-9 9/14/92 <br /> ERS I <br /> t , <br /> � i 2 .0 GROUND WATER <br /> i 2 . 1 LOCAL GROUND WATER FLOW <br /> F <br /> Ground water flow direction in this region is to the west and <br /> towards south Stockton from the foothills of the Sierra Nevada <br /> k Mountain Ranges , and towards the east from the Sacramento--San <br /> [ Joaquin Delta. At present, encroachment of saline waters from the <br /> kDelta is impairing the quality of the ground water in the Stockton <br /> area. <br /> Based upon ground water elevation measurements obtained thoughout <br /> the evaluation of this site, the overall local flow direction is <br /> to the east-northeast at a relatively flat slope. Slug tests <br /> performed on the monitoring wells (May 25 , 1990) indicated <br /> hydraulic conductivities (K) , ranging from highs of 45 . 43 and <br /> 33 . 48 feet/day at MW9 and MWI respectively , to lows of 0 . 52 and <br /> 1 . 99 feet/day at monitoring wells MW2 and MW10 respectively. <br /> These drastically different K values ( in the above mentioned <br /> �5rh wells ) along with the monthly depth to ground water measurements <br /> help determine if the ground water beneath the site is in a <br /> recharge or discharge cycle. If the ground water surface shows <br /> ii flow occuring from MW1 towards MW2 , a recharge cycle is occurring . <br /> If the ground water surface shows flow occuring from MW2 towards <br /> MW1 , a discharge cycle is occurring. Measurements obtained on <br /> July 15 , 1992 , show a continue discharge cycle, with ground water <br /> lijj I highs at MW2 , MW4 and MW9 flowing towards a depression that formed <br /> �! I from MW10 towards MW1 , Figure 4A. <br /> Measurements obtained on August 14 , 1992 , (Figure 4B) , show a <br /> E#, I continued decline in ground water elevations with the exception of <br /> MW3 which indicates a recharge to this well . The flow direction <br /> flows radially from MW3 with pronounced depressions forming at <br /> j MW2. MW4 and MWS . This figure represents a continuation of the <br /> discharge cycle that was initiated in February, 1992 . The dome of <br /> ground water that has formed around MW3 may be attributed to : the <br /> slower discharge (recovery) of the silty clayey sands , to vapor <br /> extraction vacuum at the MW3 pulling the ground water up the well <br /> and/or a interval located at MW3 which has been recharged locally . <br /> 2. 2 GROUND WATER QUARTERLY SAMPLING <br /> tl <br /> Ground water samples have been collected since December 9 , 1988 , <br /> see Table 1 . These samples were collected by a WEGE geologist and <br /> "Chain of Custody" hand delivered on ice to a state certified <br /> testing laboratory (McLaren Analytical or Chemtech (MATRIX) <br /> Analytical Laboratories ) for chemical analyses . These samples <br /> were analyzed for TPH and BTEX concentrations using EPA Methods <br />. + 8015 and 502 respectively. Since diesel has never shown up in the <br /> PAGE 3 <br /> i <br />