Aquifer volume up 350,000 acre-feet in 2020

BOISE -–The Idaho Water Resource Board's latest analysis of aquifer water levels shows that the volume of water stored in the Eastern Snake Plain Aquifer has increased more than 350,000 acre-feet this year and 2.2 million acre-feet in the last five years.

Mike McVay, an IDWR hydrogeologist, explained his method for estimating the change in the volume of water stored in the ESPA, which relies on water level measurements from 269 groundwater wells and a conservative approach to provide more confidence in long-term trends. “I removed some of the flashier wells that are close to recharge sites to increase our confidence,” McVay said.

Aquifer discharge in the Thousand Springs area and along the Snake River between Blackfoot and Minidoka also is trending upward over the last five years, IDWR hydrologists said.

“If we’re seeing higher levels in the aquifer, we should be seeing higher discharge from the springs – the primary outlet for the aquifer,” noted Matt Anders, IDWR hydrologist.

In an annual accounting of the aquifer withdrawal reductions agreed to by ESPA groundwater users in the 2015 historic water settlement between the Idaho Ground Water Appropriators (IGWA) and the Surface Water Coalition, IGWA has met and exceeded their annual target of 240,000 acre-feet of water in the last year, officials said.

IGWA members reduced groundwater use by 260,000 acre-feet and provided an additional 90,000 acre-feet of water as aquifer recharge, said Brian Ragan, an IDWR hydrologist who tracks the settlement agreement on an ongoing basis.

“What a great time to work on water resources because I get to share in your accomplishments,” IDWR Director Gary Spackman told the Board.

“It’s great to see the upward trend continuing,” added Board Chairman Roger Chase. “Our plan is working.”

In other news, the Board approved 12 flood-management grants statewide at a cost of $860,000. The Board followed staff recommendations and rankings of 14 projects that were submitted statewide.

The grantees are as follows:

Lewis Soil Conservation District - $18,425.30

Clearwater Soil and Water Conservation District - $24,687

City of Bellevue - $57,880

Twin Falls Canal Company and City of Twin Falls - $51,000

Flood Control District #10 – Eagle Island North Channel project - $47,500

Flood Control District #10 – Canyon County project - $175,000

City of Orofino - $200,000

Idaho Soil and Water Conservation District – Lower Cottonwood Cr. project - $27,935

Idaho Soil and Water Conservation District – Sill Creek project - $10,960

Idaho Soil and Water Conservation District – Clear Creek project - $18,570

Raft River Flood Control District #15 - $80,525

Pioneer Irrigation District - $148,500

All projects required a 50 percent match. See this link for more detail on the flood grants:

https://idwr.idaho.gov/files/iwrb/2020/20200730-IWRB-Board-Meeting-Materials-6-20.pdf

In other action, the Board received a briefing on the Boise River Feasibility Study, which is evaluating the feasibility of raising Anderson Ranch Dam by up to six feet on the South Fork of the Boise River to create more storage water. A Draft Environmental Impact Statement was released on Friday, July 31, on the BOR’s web site: https://www.usbr.gov/pn/studies/boisefeasibility/index.html

The public comment period opens on July 31 and will close on Sept. 14, BOR officials said. A virtual public meeting is planned for Aug. 26 from 6-8 p.m.

The Board also approved the use of funds from the Idaho National Laboratory and the U.S. Department of Energy to track groundwater levels and water quality in the Raft River area.

For more information on the July 30 Board meeting, go to:

https://idwr.idaho.gov/files/iwrb/2020/20200730-IWRB-Board-Meeting-Materials-6-20.pdf