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Aquifer Testing Standard Operating Procedure SWE-FSOP-500,•Revision 0 Ahtna Southwest Environmental Operations 1.4 Definitions Aquifer Test. Physical test to determine the hydrologic characteristics of confined or unconfined aquifers. Slug, specific capacity, step-drawdown, and constant rate pumping tests are commonly used testing methods. Bailer. A bottom-filling cylindrical tube with a check valve at the bottom. Bladder Pump. A positive-displacement pump is used to pump groundwater to the surface from most depths. A bladder pump can be small enough to pump water from wells as small as 3/4-inch in diameter. Cone of Depression. A depression in the groundwater table or potentiometric surface that has the shape of an inverted cone around a well from which water is being withdrawn. Constant Rate Pumping Test. Aquifer test involving discharging water at a constant rate from a well by pumping and monitoring the corresponding water level drawdown. The recovery of water levels in the well may also be monitored after pumping has terminated (recovery test). Water level monitoring during a pumping and recovery test commonly includes the pumping well and one or more nearby observation wells. In certain instances,observation wells are unavailable, and water level monitoring is limited to only the pumping well. Hydraulic Conductivity(K). A quantitative measure of the ability of a porous material to transmit a fluid. It is also defined as the volume of water flowing through a unit cross-sectional area of porous material per unit of time under a unit hydraulic gradient (1/t). Observation Well. A non-pumping well used to observe the groundwater levels during pumping testing. Peristaltic Pump. A negative air pressure pump used to draw groundwater to the surface. These pumps can be used if the depth to water is less than approximately 25 feet. Potentiometric Surface.The surface defined by water levels from multiple wells that penetrate an aquifer or hydrogeologic unit.Also, a map of the hydraulic head of an aquifer. Pressure Transducer and Data Logger. An electric sensor that measures hydrostatic pressure to determine depth below the water level.The data logger can store periodic water level measurements for later recall and data evaluation. Recovery.The time rate of return to the static water level during a slug test or after cessation of pumping. Saturated Thickness (b). For unconfined aquifers, the interval between the water table and the base of the unconfined water-bearing unit. For confined aquifers, the interval between the base of the upper confining unit and the top of the lower confining unit. Slugging Rod-A large metallic or PVC rod (or cylinder) of known volume lowered into the well to displace the water during a slug test. Sometimes called a "pig." Slug Test.Type of aquifer test completed by instantaneously changing the water level in a well by adding, removing, or displacing a known volume of water and then monitoring the water level recovery in the well. Specific Capacity(C). Discharge per unit of drawdown in a pumping well (Q/s). Page 5 of 17