Two bills approved by the Idaho Legislature are expected to enhance water management in the state, Idaho Water Resource Board officials said following its March 29 meeting.

“Some water users will be affected by these proposed changes,” said IDWR Director Mathew Weaver in a press release. “We need to do more research to understand how many water users could be affected. We will officially notify affected water users in the coming months about the change in administrative scope and the impact on their individual water rights.”

The first bill, House Bill 687, would allow the Idaho Department of Water Resources to petition a District Court judge to commence a water rights adjudication in North Idaho's Kootenai River Basin, most of which lies in Boundary County and a small percentage in northern and northwestern Bonner County. Local legislators supported an adjudication in the basin to define and confirm existing water rights. 

Water rights adjudications are under way in the Bear River, Clark Fork-Pend Oreille, Coeur d’Alene-Spokane River, and Palouse River basins in Idaho. The Snake River Basin Adjudication, completed in 2014, was the largest water rights adjudication ever completed in the western United States.

The Kootenai River Basin Adjudication is expected to take five years and cost $3.25 million, using existing IDWR staff to work on the project, officials said. 

In Idaho, citizens have natural water rights for domestic and stockwater use — also known as de minimis water rights. For surface waters such as springs, creeks, and lakes, uses that started before May 20, 1971, and in-stream stockwater uses regardless of the date, do not require the water user to file for a water rights permit with IDWR. Any use of surface water that started after May 20, 1971, requires a water rights permit with IDWR, except for allowing livestock animals to drink from a stream.

The second bill, Senate Bill 1341 creates a process for IDWR officials to expand the boundary of the Eastern Snake Plain Aquifer area of common groundwater supply. The bill passed both chambers of the Legislature in an unanimous vote; it was signed by Gov. Brad Little on March 20.

Adjusting the boundary of the ESPA area of common groundwater supply is needed to conform with the latest and most accurate ESPA groundwater model.

The change would ensure that IDWR’s management of surface water and groundwater rights in the aquifer could be accomplished under the Prior Appropriation Doctrine, officials said. Under that water law, senior water users, or those who have the oldest water rights, receive priority in times of water shortages, officials said.

SB 1341 provides for a process for IDWR to follow to notify ESPA surface and groundwater users about the proposed change in boundary, hold public hearings and take public feedback. The bill also provides an opportunity for water users to appeal the final decision.

The Idaho Water Resource Board said two pieces of legislation passed by the Idaho Legislature in the 2024 session will enhance water management in North Idaho and southern Idaho.