In 2009, the Eastern Snake Plain Aquifer (ESPA) Comprehensive Aquifer Management Plan was passed into law by the Idaho State Legislature. The plan establishes a long-term program for managing water supply and demand in the ESPA through a phased approach to implementation, together with an adaptive management process to allow for adjustments or changes in management techniques as implementation proceeds. Because of the inherent complexities in the management and responses of the river and aquifer to water budget changes, a very deliberate choice was made to incrementally implement the various mechanisms proposed in the plan.
The objectives of the plan are to:
- Increase predictability for water users by managing for a reliable supply.
- Create alternatives to administrative water-use curtailment.
- Manage overall demand for water within the Eastern Snake Plain.
- Increase recharge to the aquifer.
- Reduce withdrawals from the aquifer.
Sustain the economic viability and social and environmental health of the Eastern Snake Plain by adaptively managing a balance between water use and supplies.
The Eastern Snake Plain Aquifer
The ESPA is a key element of southern Idaho’s economy and covers approximately 10,800 square miles of Idaho. The ESPA region produces approximately 21% of all goods and services within the State of Idaho—resulting in an estimated annual value of $10 billion. Water is the critical element for this productivity.
For a variety of reasons, groundwater levels in parts of the ESPA declined, leading to a cumulative decrease in aquifer storage, decreased spring flows, and changing Snake River flows that resulted in insufficient water supplies to satisfy existing beneficial uses. IWRB , at the request of the Idaho State Legislature, prepared and submitted a Comprehensive Aquifer Management Plan to address the water supply-and-demand imbalance.