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Or <br /> }}t � 5. 0 PROPOSED MONITORING PLAN <br /> Lp <br /> } To determine if ground water contamination has occurred as a <br /> result of past underground leakage of gasoline at the Rainbo <br /> Baking Company plant, three ground water monitor wells will be <br /> constructed after obtaining well permits from the San Joaquin <br /> 'W Local Health District (See Figure 5-1 for well construction <br /> details) . The monitor wells will also be used to determine <br /> the ground water gradient at the site, and Figure 5--2 shows <br /> the proposed locations of the monitor wells. Assuming the <br /> regional ground water flow direction ( northeasterly ) exists at <br /> the site, the well to the sou,:hwest of the former tank <br /> �a locations is considered an upgradient well, and the wells <br /> l� located north and east of the former tank locations are <br /> considered downgradient wells. However, if after installation <br /> of the three wells, the ground water gradient is not to the <br /> f <br /> northeast., southwest, or east (the direction in which the <br /> 3 wells are to be located ) , a fourth well will be installed in <br /> the downgradient direction. <br /> The borings for well construction will be accomplished by <br /> t ; using a hollow stem auger and mud rotary drilling. Split <br /> spoon soil sampling will be performed at 5 ft intervals from <br /> the ground surface to the depth of ground water, and at <br /> selected locations to further characterize significant changes <br /> in 3ithology. Samples will also be taken just above and below <br />+� the water table. If the soil samples at the ground water <br /> u1 c. table indicate possible ground water contamination (as <br /> � { detected by visual observation and/or PID readings ) , the <br /> boring will not be converted into a well, but filled to the <br /> ground surface with grout. Another boring will be drilled in <br /> i <br /> the same direction but further away from the excavation. If <br /> no contamination is detected in the soil samples at the ground <br /> water table in this boring, the boring will be converted into <br /> t ; <br /> a well , <br /> 5-1 <br /> n. <br /> -awv�� Nmlitll�i41 il�i3[i1�I4�MA1 101111 ����®f�1rRwLwm1 <br />