4.3.4 Economic and Environmental Impacts of Pumping with Well Loss. The water level is determined to have dropped no greater than 200 feet through the duration of the test or The most common single-well methods involve step-drawdown test analyses that are.The well yield is determined by dividing the average discharge (in gallons) by the average interval (in minutes) between each time the pump was shut off.įor recovery rates of 4 gallons/minute or greater, testing may be terminated after three hours if: Record the time and repeat this process at least three times to determine the recovery rate (well yield). 1 Step-drawdown tests (SDTs) typically involve pumping a well at a constant rate until a quasi-steady state (QSS) is observed in the drawdown response. Wait a set period of time (15 minutes) turn the pump back on and measure the discharge of the water until the water level is drawn down to the pump intake again. If the water level is drawn down to the pump intake turn the pump off and record the time.Time, flow rate, and pressure readings must be recorded every 15 minutes. The pump should be turned on and the manifold valve opened completely.The testing manifold must be connected so that the pumping switch mechanism is bypassed.The contractor performing the test shall provide a testing manifold consisting of an inlet for connection to the pressure line from the well and a tee with a pressure gauge graduated with intervals of at least 2 pounds per square inch (psi) and capable of measuring up to 200 psi.Yield tests for existing wells in which a submersible pump has been installed and connected to a water distribution system may be performed in accordance with the following procedure: The format is not important as long as it includes time-drawdown information. This number may differ from the well yield results produced at the time of drilling, as the bottleneck will have been eliminated. 1, Data Entry Template for Pumping Tests. The last 5-gallon reading is determined to be the "well flow" or "yield" for that well.īecause water runs through the bottlenecks of the well pump and pressure tank, 10-12 gallons per minute is usually the best result for the test. This 4-hour quantity test will produce the following calculated results: Static Water Level, 24-Hour Total Volume, Sustained Pumping Rate, and Recovery Rate of the well. Water is run from the well in five-gallon intervals. Some local Boards of Health require a 4-hour drawdown test, while other towns either have no specific requirement or will accept a 1-hour test. For best results, water should be taken directly from the pressure tank whenever possible.
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