Consider the hypothetical desert-basin, stream-aquifer system, as illustrated in Figure 17. Does the position of the pumping well relative to the stream affect the response of the system? Specifically, how does it affect (1) the magnitude and timing of the effect of pumping on surface water, and (2) the relative sources of water to the well? What is the nature of these effects? Consider two alternative well locations – one further from the river and one closer to the river. Are any or all of these pumping scenarios sustainable? If you were a water manager for this stream-aquifer system, which well location would you consider preferable, and why? And are there any tradeoffs, such as the amount of drawdown in the pumping well?
Suggested approach: Download the files for the Case Study 1 model as described in Box 3. To determine the effect and importance of the distance between the well and a stream, if any, generate and simulate two additional variants of the base case in which the well position is changed. Move the location of the pumping well a distance halfway closer to the river (to the east) for one variant, and then also halfway closer to the distal “mountain” boundary (to the west). For these two new cases, the distances from the well to the center of the river are 4 km and 20 km, respectively. In the original “base case,” that distance was 8 km (Figure 17). Plot the depletion and capture fractions over time for 200 years. The analyses can be completed using public domain United States Geological Survey software.