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Mr. Sasson �J Pag e 2 June 15, 1995 ,p Original laboratory reports, including PNA results and copies of ch ain-of-custod}r { forms, are enclosed with this letter in Attachment 2. i Table 2 shows groundwater elevations measured at the three monitoring wells. A potentiometnc groundwater elevation map based on the groundwater measurements is providedin Figure 2. Table 2 April 1994 Groundwater Elevations Well # Casing Elevation GW Elevation MW-4 +5,87 ft -18.71 ft f ISN-5 +6.08 ft -19.05 ft I M W-6 +6.88 ft -18.93 ft 1 t� � Groundwater Gradient Correction An error was recently discovered in the surveying of the well elevation at well MW-6. The monitoring wells were surveyed in 1991 by a State of California Licensed Land Surveyor. The top of casing elevation at monitoring well MW-6 was reported to be 5.87 feet above mean sea level (msl). The corrected elevation is 6.88 feet above msl. The documents prepared by ERM had consistently shown groundwater flow in a . southeasterly direction. Revised calculations of the groundwater flow direction with F the corrected well casing elevation show groundwater moving in an easterly direction. The revised flow direction is consistent with measurements taken in September 1989. Figure 3 shows the corrected groundwater flow direction for the December 1994 monitoring, previously submitted to the County. Site Stagy Due to the adjusted direction of groundwater flow, Safeway is currently in the process j ' - of reviewing past data. When the review has been completed, a meeting will be held between Safeway and the County, recently scheduled for June 23. After the meeting, ; Safeway will provide the County with a workplan designed to achieve site closure. i Sincerely, ' � it , ERM-WEST, INC. r'yt William A.€i Spong Project Manager WAS/1218.04 Attachments: Noted cc: Melita,EElmore (Safeway), Dennis Miller i ri