BOISE — The Idaho Water Resource Board surpassed the 250,000 acre-feet milestone this week in terms of recharge flows going into the Eastern Snake Plain Aquifer this winter.
The board still expects to recharge as much as 370,000 acre-feet by spring, building upon last year's record of 317,000 acre-feet of ESPA recharge last year. The board has until mid-April or the beginning of irrigation season to send water flows into the ESPA under its winter water rights.
“It’s imperative to recharge as much water as possible during these surplus water years,” said Wesley Hipke, recharge project manager for the board.
The Board has committed to recharging an average of 250,000 acre-feet into the ESPA each year to help restore the aquifer to sustainable levels. It has been overdrafted by about 200,000 acre-feet per year since the 1950s.
The recharge flows — combined with a commitment from the Idaho Ground Water Appropriators under an historic settlement agreement to reduce their water use from the ESPA by 240,000 acre-feet — are expected to bring the aquifer into balance and restore its long-term viability.
The water resource board pays canal companies and irrigation districts on an acre-foot basis to distribute water from the Snake, Big Wood and Little Wood rivers via canals and settling basins throughout the ESPA region, allowing water to seep into the aquifer.
The Board benefitted from a quick start to recharge operations late last August with a contribution of 61,100 acre-feet of surplus water from the Surface Water Coalition. There also has been a big surplus of water stored in Upper Snake River reservoirs, which caused the U.S. Bureau of Reclamation to release more water than usual below Minidoka and Milner dams this winter.
More than 115,300 acre-feet have been recharged in the Upper Snake region, and more than 138,343 acre-feet has been recharged in the Magic Valley region, with multiple canal companies and irrigation districts participating in both regions.