Hantush Automatic
Hantush Leaky Aquifer Automatic Analysis
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Recommended for:
- Leaky confined aquifers
- Simultaneous analysis of data for several wells
- Analyzing trends from early to late time to look for possible hydrogeologic boundaries
- Pump tests that have reached steady state
This is the Hantush Steady State Inflection Point method implemented by the slope matching techniques presented by Sen (1986). The solution requires no curve matching needed. At least three pairs of time/drawdown values are necessary to use the method however the method is not practical with less than about ten. The last drawdown value must be the steady state drawdown.
Slope-Matching Implementation
The method works by matching the slope of the data to the slope of a theoretical drawdown curve. Transmissivity, storativity, and leakage factor are calculated for pair of consecutive pairs of time/drawdown measurements. For n trials, n-1 transmissivity values and n-1 storativity values will be calculated.
Unsolvable Values
The slope matching method is based on theoretical principles. In real pump tests, some data anomalies will cause the calculations to fail for certain data pairs. If transmissivity and storativity can not be calculated, "-----" will appear in the output file.
A decrease in the drawdown to consecutive time measurements, due to variation in pumping rate, or error in measurement, will cause the method to fail for those values. For some pump tests with very little drawdown, it is possible that there may be no successful calculations of transmissivity, storativity, and leakage factor. This may indicate that the pumping rate did not significantly affect the aquifer for the solution to be valid.
Some data points may result in individual calculation results that vary significantly from the mean. These point should probably be excluded from the final calculations.
Applicability
This method is applicable for any leaky aquifer scenario where the Hantush solution is valid.