SITE INFORMATION AND CORRESPONDENCE

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� ` ~ ^�°� ~ ^ The ground water flow direction on 12/02/87 was directly towards the domestic well located about 140 feet northwest of the excavation. This probably resulted from pumpage from this well ; � the well is probably hydraulically connected to the water table aquifer ( a well log is not available ) . The 147. 5 degree swing in the direction of ground water flow between 12/03 and 12/21 is most likely attributable to either a cessation of pumpage in the domestic well , or the onset of heavy ` pumpage from a nearby well to the east of the site. Since the � magnitude of the gradient on 12/21 is twice that on 12/03, the , writer feels that most likely, the flow direction swing results � from heavy pumpage to the east of the site. This change in the ground water flow direction has apparently caused a regulatory problem at this site. The problem stems from the requirement that a monitoring well must be installed and sampled down gradient from the source of contamination. Since the gradient has swung around, it is hard to tell just where down gradient is. Thus, planning for a well location is complicated. Recently, W. H. Fox II of WIN Environmental Consultants, remeasured the ground water level in these wells. The wells were measured on 9/ 16 , 9/30 and 10/07/88. The writer constructed a three point problem to determine direction and magnitude of the ground water gradient. This time, there was even yet another solution to the problem which follows: 9/16 - 9/30 - 10/07 --- N 25 E @ . 256 ft / 100 ft This represents an average of the three readings, the maximum variation of which was 0. 07 ft. The readings for each of the three wells for each of the three days are shown in the appendix , along with well readings for toe measurements in December of 1987. ' ) The possible contamination at this site results from a rupture of a 1500 gallon tank as it was being removed from the site. The writer understands that approximately 20 to 50 gallons of motor oil escaped from the ruptured tank, into the bottom of a 7 foot deep excavation. The spill was cleaned up by excavation of the soil in the bottom of the hole. This took about 15 minutes; the hole was deepened from 7 to 12 feet. During the deepening of the excavation, ground water was encountered. Approximately 4 cubic yards of material was excavated from the hole. Water from the bottom of the excavation was sampled . The lab results disclosed 39 ppm motor oil , 20 ppb benzene and 50 ppb xylene. The above was told to the writer by W. H. Fox II , who was ^ . present at the time of the incident. 3