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i' It Chevron Products Company 5 Former Chevron Service Station 95775, 301 West Kettleman Lane Lodi, California March 30 2000 step, and also to provide Information needed for the selection of an appropriate extraction rate for the long-term constant -rate test The step -drawdown test performed in pumping well EX -3 consisted of four discrete pumping steps The total available drawdown in pumping well EX -3 is approximately 22 feet Step pumping rates of 5 0, 7 2, 9 0, and 11 0 gallons per minute (gpm) were used, and the test lasted a total of 150 minutes At the aforementioned step rates, water levels stabilized at 45, 30, 30, and 45 minutes, respectively A constant flow rate was maintained throughout the duration of each step The flow rate was Increased to a new step after the drawdown in the pumping well (well EX -3) stabilized Transducer readings and flow rates were tabulated and graphed throughout the step -discharge test For the step rates of 5 0, 7 2, 9 0, and 11 0 gpm, drawdown effects of 2 3, 4 3, 5 7, and 10 5 feet, respectively, were observed In addition, drawdown was also observed in monitoring well MW -1 After completion of the step - discharge test, the data was downloaded from the data -logger onto a portable computer and backed up on diskette Based on the step -drawdown test data, a rate of 9 0 gpm exhibited adequate stress on the aquifer without exceeding the available drawdown and potentially risking pump cavitation later during the pumping period CONSTANT -RATE PUMPING TEST iThe constant -rate pumping test was performed between November 22 and 27, 2000 The objective of the long-term pumping test was to Impose hydraulic stress on the aquifer by pumping from the selected pumping well and then monitoring the drawdown effect in the observation wells The resulting drawdown data was then used to evaluate the response of the aquifer to pumping, and estimate aquifer parameters including T, S, and K, for the aquifer The constant -rate pumping test consisted of background, pumping, and recovery phases The long-term constant -rate pumping test Included the three components described below • Background Data Collection Phase — Prior to pumping, static and non -pumping water levels were monitored During the background phase, water levels were monitored in the pumping well and observation wells for a period of 192 -hours prior to initiating the pumping phase This portion of the test is used to assess regional water level trends including barometric efficiency * Pumping Phase — Long-term pumping in a single well at a constant rate to produce the desired stress in the aquifer and to monitor the resulting changes in water levels in observation wells During the pumping phase, a constant pumping rate was maintained for a 120 -hour period while monitoring drawdown effects in nearby observation wells I \Chevron1957751Agtnfer test\Revised195775Aquifertestrevised doc