Idaho Water Board discusses drought, aquifer issues

Drought in the Idaho Panhandle has made it more difficult for water managers to maintain both summertime lake levels and streamflow below the lakes this summer.

That was one of the focuses of the Idaho Water Resource Board meeting held in July in Post Falls.

During its meeting, the water board toured sites within the Rathdrum Prairie Aquifer and Spokane River system where members learned about the water management challenges facing North Idaho. Low snowpack and streamflows have measured 10-20 percent of normal this year.

"It's a difficult balancing act to provide enough water for full lake levels and adequate stream flows, which has been exacerbated by drought conditions in North Idaho this year," said Brian

Patton, chief of the planning and projects bureau for the Idaho Water Resource Board.

The board also learned about the complexities of the Rathdrum Prairie and Spokane Valley Aquifers which interact closely with the Spokane River. Spokane River flows from Lake Coeur d'Alene naturally seep into the aquifer as the river flows west into Washington, significantly reducing river flows until water begins to come back to the river from the aquifer near Greenacres gage to the city of Spokane gage.

"The flows in the Spokane River in this stretch are more dictated by aquifer recharge and discharge than surface water from Coeur d'Alene Lake and Post Falls Dam," said Roger Chase, chairman of the Water Resource Board. "The dynamics of the geologic foundation of the river and the aquifer rule the day."

Due to the complexity of the aquifer and river system, officials in both Idaho and Washington monitor groundwater levels in the aquifer and how groundwater pumping impacts river flows. The board heard an update from Idaho Department of Water Resources staff on the Rathdrum Prairie Aquifer 28-well groundwater monitoring network.

Paul Kimmell from the Palouse Basin Aquifer Committee provided an update on efforts to initiate a study of alternatives to address declining aquifer levels and increase water supplies. The Palouse Basin Aquifer has been dropping continuously since the 1890s. It has dropped 40 feet in the last 40 years. The Palouse groundwater basin is the sole source of water for more than 60,000 residents of Moscow; Pullman, Wash.; and the outlying areas of Latah County in Idaho and Whitman County in Washington.

"The board is focused on supporting water projects statewide and understanding the water supply and management challenges facing water users across the state," Chase said.