Therefore, it is possible to use the geometry of resistivity anomalies to estimate the hydraulic conductivity of the unconfined aquifer using the distance-drawdown equation for pumping tests in unsaturated aquifers.
Consistent distance-drawdown responses in all wells within a 3 km radius of the pumping well indicate that the ER-20-7 drawdown estimates are plausible.
The volume of aquifer system that can be characterized with aquifer tests is controlled by the distance at which drawdown can be detected.
This indicates that residual differences from the fit are driven by the measured environmental fluctuations rather than the drawdown magnitude or distance from the pumping well.
The monitored results indicate that the drawdown outside the pit at a distance of 1 5 m to the wall is less than 2 m, while the maximum land subsidence is 7.97 mm, which is of nearly no influence on the environment around the pit during dewatering.
Drawdown detection typically is limited to distances of less than 1 km, because environmental water-level fluctuations frequently exceed the maximum displacement from pumping (Risser and Bird 2003).
Figure 3 Drawdown as a function of time for a fixed distance.
Figure 2 Drawdown as a function of space and time.
This drawdown will continue.
Pressure buildup analysis and drawdown.
