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REG 603 UPDATE-7 3/24/92 <br />.' <br /> 1. 99 feet/day at monitoring wells MW2 and MW10 respectively. <br /> These drastically different K values (in the above mentioned <br /> 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 /> 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 /> January 21, 1992, (Figure 4A) , show a flow direction to the <br /> northeast and east, with a flow from monitor well MW1 towards MW2 <br /> forming a trough and indicating a recharge cycle is occuring. <br /> On February 4, 1992, (Figure 4B) , depth to ground water was again <br /> measured from top of casing in all of the wells. The flow <br /> direction was established to the south, southwest and southeast <br /> with a ridge forming in the slower velocity sediments from MW2 <br /> towards MW10 and then out to MW4 . This figure indicates a period <br /> of discharge has formed a valley at MW1 with a ridge forming at <br /> the lower velocity wells MW2, MW10 , MW4 and MW9 . <br /> Figure 4C represents the ground water gradient from measurements <br />• obtained during the March 10 , 1992, quarterly ground water <br /> sampling. Ground water appears to flow radially from MW3 with a <br /> pronounced valley forming from MW2 towards MW1. This figure <br /> represents a continuation of the February period of discharge. <br /> The dome of ground water that has formed around MW3 and MW10 can <br /> be attributed to two factors; the slower recovery of the silty <br /> clayey sands and also to vapor extraction vacuum at the wells <br /> pulling the ground water up the wells. <br /> 2 .2 GROUND WATER QUARTERLY SAMPLING <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 602 respectively. Since diesel has never shown up in the <br /> , i_ the 1 obtained frog 1 1 /77 /00 anti 1 atar G7PY'P <br /> ScL![L�lle Le51.l11�u, 411G aa�i�pl.eS vs,r�.aiiicu iivut i1/ s. / <br /> analyzed using EPA methods 5030 and 602 for Total Fuel <br /> Hydrocarbons and BTEX, see Appendix B. Complete chemical results <br /> are presented in Table 1 of this report. <br /> 2 . 3 SAMPLING PROCEDURES <br /> Prior to opening the air/water tight well cap a vacuum reading is <br /> obtained from the well using a monometer calibrated in millimeters <br /> (mm) of water. This reading is then converted to feet vacuum at <br /> PAGE 3 <br />