Attenuation, Delay and Spatial Propagation of Pumping Effects: Response Functions and Double-Entry Accounting

When the prior-appropriation administration of groundwater use and surface-water use are linked, it becomes necessary to quantify in time and space the depletion effects that pumping has upon surface water.  The propagation of pumping effects is dampened and delayed in transit through the aquifer.  If more than one surface-water body is hydraulically connected to the aquifer, the pumping effect must be partitioned between the surface-water bodies for just and equitable administration of prior appropriation.

In large aquifers such as the Eastern Snake River Plain Aquifer of Idaho, different pumping locations can vary trememdously in the degree of dampening and the time of delay of propagation of pumping effects.  Simple mass-balance accounting that ignores temporal differences in matching mitigation to pumping can injure surface-water right holders and natural systems.

One administrative alternative is the individual calculation of depletionary effects for each individual transaction (i.e. withdrawal permit application or change in point of diverison application).  This has proven to be costly and time consuming.

If aquifer response functions are used to quantify the propagation of effects in time and space, all events may be condensed into a "common currency" of time series of effects at surface water bodies.  If double-entry accounting principles from the financial-accounting field are adopted, all impacts and activities can be addressed in a single administrative system.  The power of this mechanism is that it automatically enforces the prior-appropriation "no-harm rule" and at all times maintains a record of past impacts and a projection of future impacts upon surface water resources.

If an administrative goal is to allow market forces to aid economically-efficient exchange and allocation, this mechanism also provides market-requisite transparency, information, and commodity homogeneity.