Groundwater Recharge to Address Integrated Groundwater and Surface Waters: The ESPA Recharge Program, Eastern Snake Plain, Idaho

The Eastern Snake Plain Aquifer (ESPA) Recharge Program aims to recharge an average of 250,000 AFY to mitigate the effects of groundwater pumping on surface water resources and, in doing so, to reduce conflicts between surface and groundwater users. The Idaho Water Resources Board (IWRB) partners with canal and irrigation companies to use IWRB's surface water rights to conduct aquifer recharge through in- and off-canal seepage and direct injection wells. The canal and irrigation companies are paid by IWRB to use their canals and property for recharge sites. From 2014 to 2019, the program achieved 249,028 AFY of average recharge per year. The ESPA Recharge Program serves as a good example of a statewide recharge program that addresses challenges in managing highly connected groundwater and surface water. Moreover, it illustrates the incentives that can emerge for joint management of groundwater and surface water based on legal regimes that integrate the two. The ESPA Recharge Program particularly benefited from its centralized structure, with one state agency, IWRB, given sole control of implementing the recharge program. Nevertheless, the program faces some future obstacles, namely, in securing long-term funding, building out conveyance capacity to transport water to recharge sites during wet years, and modeling groundwater resources adequately.