Combine observation and derivative data on a single plot for more effective curve matching!
Only available in AQTESOLV Professional, derivative analysis is powerful diagnostic tool that enhances the interpretation of data from pumping tests. Features difficult to discern in drawdown data alone are often readily apparent through the application of the derivative procedure. Groundwater hydrologists use derivative analysis to identify important flow regimes encountered during a pumping test, detect aquifer boundaries and select appropriate aquifer models.
Derivative analysis has its origins in the petroleum industry literature (Bourdet et al. 1983; Bourdet et al. 1989) and has been gaining attention among groundwater hydrologists for a number of years (Spane and Wurstner 1993; Renard et al. 2009).
In addition to providing this diagnostic method of analysis, AQTESOLV also lets you perform interactive visual curve matching with derivative plots to estimate aquifer properties.
A derivative plot for a pumping test in a nonleaky confined aquifer is shown to the right. You can use interactive visual curve matching to match both curves (drawdown and derivative) simultaneously.
Computation of the derivative requires numerical differentiation of drawdowns. Straightforward calculation of the derivative using neighboring points typically results in noisy data. Consequently, smoothing techniques are employed to reduce noise. AQTESOLV features three smoothing options including the methods of Bourdet et al. (1989) and Spane and Wurstner (1993).