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THE “CHEAT SHEET”: A NEW TOOL FOR THE FIELD EVALUATION OF WELLS BY STEP‐TESTING
Author(s) -
Kelly Jack E.,
Anderson Keith E.
Publication year - 1980
Publication title -
groundwater
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.84
H-Index - 94
eISSN - 1745-6584
pISSN - 0017-467X
DOI - 10.1111/j.1745-6584.1980.tb03403.x
Subject(s) - drawdown (hydrology) , extrapolation , artesian aquifer , dolomite , aquifer , geology , yield (engineering) , geotechnical engineering , line (geometry) , soil science , statistics , mathematics , mineralogy , groundwater , geometry , materials science , metallurgy
Step‐testing of wells penetrating a jointed, fractured, sometimes cavernous limestone‐dolomite artesian aquifer showed characteristic patterns of extreme variation in specific capacity at different discharge rates. The application of principles developed by Jacob for well‐loss determinations, and subsequent modifications by others, did not yield meaningful results. It was found that a log‐log relationship between discharge and drawdown, through a large number of steps, could be used to evaluate the degree of nonlinear head losses in and near the well bore and make possible the extrapolation of drawdowns at higher discharge rates. This technique also has been used to estimate transmissivity which, in at least one instance, was confirmed by the subsequent evaluation of observation‐well data by both straight‐line and type‐curve methods. The easy use and rapid initial evaluation of test data afforded by this method gave rise to the name “Cheat Sheet.”