ABSTRACT
The third step in aquifer test modeling is the review of the mathematical modeling equation assumptions and the adjustment of data for any departures (herein called external influences) from the assumptions. Erroneous conclusions about aquifer parameter values and boundaries can be reached if the impacts of any external influences are not removed before aquifer test data are analyzed with mathematical modeling equations. External influence fluctuations include those caused by groundwater flow through the aquifer test domain prior to the test (antecedent trend), atmospheric pressure changes, surface water (tidal, lake, or stream) stage changes, earth tides, earthquakes, applications of heavy loads (railroad trains or trucks), evapotranspiration, recharge from rainfall, and nearby pumped well pumping rate changes.
