Response Functions & Aquifer Recharge
Most of the above discussion and examples related to depletion of streams resulting from aquifer pumping.  In conditions where response functions can be used, pumping and aquifer recharge create equal but opposite effects on stream and spring discharge.  Where ground water pumping results in a depletion of surface water resources, aquifer recharge will result in an increase in flows.  The rate of increase will be proportional to the rate of recharge.

In the second example, if the well were recharging at a rate of 2 cfs, rather than pumping, then the stream gains would have increased, rather than decreased, by 1 cfs (the response ratio was 0.5) after 100 days.

Combinations of pumping and recharge can be evaluated by adding responses from individual activities on the stream reach of interest.

Information supplied by Idaho Water Resource Research Institute, University of Idaho December 1998
Authors: Dr. Gary Johnson, Donna Cosgrove, and Mark Lovell.
Graphics: Sherry Laney and Mark Lovell
All State of Idaho images and graphics created with GIS files obtained through Idaho Department of Water Resources Public Domain GIS unless otherwise noted.
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