1. Project detail, basin map

Water users in part of the Upper Salmon River Basin must install control and measurement devices before irrigation season begins, according to the Idaho Department of Water Resources.

About 960 water users in administrative basin 75, which is part of Water District 170, were notified of the requirements in June 2024 and again recently, according to a department news release.

The devices are required on diversion infrastructure. State law requires water control and measurement devices on surface and groundwater diversions in all water districts.

Starting in 2026, water users in other areas of district 170 have been notified that they must install measurement devices on surface water and groundwater diversions and to have a means to control the flow of water, such as a headgate, according to the release.

The Salmon River has federal Wild and Scenic Rivers Act protections, and salmon, steelhead and bull trout have Endangered Species Act protections. Idaho and the federal government in the 2000s reached an agreement whereby the state retained water management largely through the water districts.

In the Upper Salmon basin, the department has been working progressively, starting with a 2008 due date in the Stanley-Clayton-Challis area. Due dates followed in 2014 and 2019 to the north and east, respectively.

This year’s installation deadline applies in the north-northeast area that includes the city of Salmon.

As the final area of the basin subject to the requirement, it is key to full basin compliance “and also improved management and to balance multi-use,” Upper Salmon basin watermaster David Graybill said in an interview. “This piece is focused on populated areas and ag activities” including pasture irrigation.

He has been informing water users, checking device compliance and answering questions. He is available for technical assistance.

Graybill and WD 170 sub-district watermasters plan to visit all 2,400 Upper Salmon basin diversions in coming years to ensure that water-control and measurement devices are installed and working properly, according to the department.

Measurement and control devices are necessary for the local watermasters to properly distribute water in the districts. Watermasters use the devices to ensure that only the authorized amount of water is diverted by each user.

Watermasters are required to record and report the amount of water delivered to each user.

Most domestic and stockwater users are exempt from the measurement requirement, according to the release. Users authorized to irrigate 5 acres or less, or users authorized to divert less than 0.24 cubic feet per second, are not required to have a measurement device but must have a lockable control structure such as a headgate.