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Hydraulics of Groundwater
Published in Mohammad Karamouz, Azadeh Ahmadi, Masih Akhbari, Groundwater Hydrology, 2020
Mohammad Karamouz, Azadeh Ahmadi, Masih Akhbari
An aquifer test (or a pumping test) is performed to evaluate an aquifer by observing the aquifer’s drawdown at observation wells. One or more monitoring wells or piezometers are used for aquifer testing as the observation/monitoring wells. Water is not being pumped from the observation well, instead, its drawdown is monitored. While water is being pumped from one well at a steady rate, the water tables are monitored in the observation wells. Typically, monitoring and pumping wells are screened across the same aquifers. Aquifer testing is based on the data processing to yield valuable qualitative and quantitative features about the subsurface geological composition of the aquifer domain. The test data processing is achieved by matching the data with an appropriate type curve. An analytical or numerical model of aquifer flow is used to match the data observed in the real world, assuming that the parameters from the idealized model apply to the real-world aquifer.
Porous Medium Aquifer Tests
Published in Zekâi Şen, for Scientists and Engineers, 2017
Hydraulic properties of an aquifer can be determined by an aquifer test that involves abstraction of water from a well at a constant rate and observing with respect to time the water level changes in the pumped and/or observation wells. Properly completed aquifer tests provide the following useful information about The general aquifer parameters, such as transmissivity, storativity, leakage factor, drainage factor, and hydraulic resistance. It is also possible to determine hydraulic conductivity if the aquifer thickness is known.The geometry of the aquifer including distance, direction, and nature of impermeable barriers and recharge boundaries.The lateral variations in the well vicinity.
Modeling and Wellfield Design
Published in Thomas M. Missimer, Ian C. Watson, Water Supply Development for Membrane Water Treatment Facilities, 1994
Thomas M. Missimer, Ian C. Watson
Design of an aquifer test is very important in order to obtain the most accurate aquifer hydraulic coefficients possible. There are a number of important factors that must be considered at each test site including the general specifications of the test-production well, the number and specifications of the observation wells, the spacings of observation wells away from the production well, the estimated test-pumping rate, the method of pump discharge measurement, the disposal of pump discharge water, the methods of measuring pressure changes in the production and monitoring wells, and several other less important factors. Some good references on the design of aquifer performance tests are Driscoll (1986) and Kruseman and DeRidder (1991).
Hydraulic characteristics of a fractured crystalline basement aquifer in Nzhelele area, Limpopo Province, South Africa
Published in Cogent Engineering, 2021
R. Makungo, J.O. Odiyo, J.G. Ndiritu
where xi and yi are the ith observed and estimated drawdowns, respectively, and n is the number of estimated parameters and n is total number of observations. Aquifer hydraulic characteristics (storativity, transmissivity and hydraulic conductivity) were computed based on the aquifer test solution model selected by the software for each set of pumping test data. Cooper–Jacob solution was also used to compute transmissivity from flow characteristics (FC) programme. Storativity values could not be estimated based on the methods used in the FC programme. This was because the methods used in the FC programme are very insensitive to changes in drawdown and the calculated storativity values are therefore biased (Dippenaar, 2008). Hydraulic conductivity was computed from the relationship: