Analysis of aquifer depletion criteria with implications for groundwater management

Groundwater is critical to many aspects of life on the Great Plains. Overdevelopment of this resource can have serious social, economic, and environmental consequences. Aquifer depletion criteria are used in many areas of the Great Plains to implement management responses and limit groundwater development. This study addresses groundwater-level triggers and depletion limits-criteria commonly used in Nebraska- within the context of interconnected ground- and surface-water systems. Generic models are used to calculate transient water budgets in three hypothetical systems given depletion limits of 5%, 10%, 15%, and 25%. In each simulation, the source of water to the wells changes from aquifer depletion to surface-water depletion, but at rates varying from 1 day to several hundred years. Separate simulations test the effectiveness of groundwaterlevel triggers at achieving a desired depletion limit. Results suggest that universal application of generic depletion criteria may lead to unintended consequences such as excessive surface-water depletion, excessive aquifer depletion, or conversely, unnecessary constraints on pumping. A holistic process framework for groundwater management is presented to promote the use of aquifer depletion criteria in conjunction with an adaptive management strategy. Such strategies can help ensure the future sustainability of water resources in Nebraska and elsewhere in the Great Plains.