Watersheds to Watch: WRIA 33 — Lower Snake River

by Nick Manning

Water Resource Inventory Area (WRIA) 33 encompasses the Lower Snake Watershed, including a large portion of the Snake River and its numerous tributary creeks and streams. Originating in the mountains of Idaho and Wyoming, the Snake River runs through southeast Washington, meeting the Columbia River before flowing west into the ocean.  Of the watershed itself, 84% is privately owned, a majority of which is cropland. As a result, most—if not all—of the available water in the Lower Snake Watershed has already been spoken for, according to the Department of Ecology (Ecology) in its WRIA 33 report. Especially during summer months when demand is highest and flow levels are lowest, growing populations, declining groundwater levels, changing climate patterns, and existing excessive damming and pollution have reduced water availability to dangerous levels for local communities and the environment. As of this report, no instream flow rule or watershed plan exists to address this issue.

The Lower Snake Watershed has been designated by the National Oceanic and Atmospheric Administration (NOAA) as critical habitat for four threatened species of salmon. As recently as 1930, half a million salmon ran through the Snake River annually, but by 1990, only 78 made the full trip. In their recovery plan, NOAA reports that more than half of historic salmon habitat has been blocked by dams, with remaining spawning areas in wide river valleys often degraded by development, withdrawals of water, and erosion. Despite being listed as threatened for decades, most wild Snake River salmon and Steelhead returns remain at about the same levels as when they were first listed in the late 1990s. More importantly, the wild returns are still nowhere near NOAA recovery targets, which must be met for eight consecutive years. Federal courts have ruled repeatedly that salmon recovery is impossible without dam removal along the Lower Snake River, but no action has materialized.

Exacerbating the damage to salmon populations and water scarcity is the issue of pollution in the Lower Snake Watershed. In a study conducted by the Natural Resources Conservation Service (NRCS), it was reported that the Lower Snake waters are degraded enough as to be listed under Section 303(d) of the Clean Water Act. This designation is reserved for waters that do not meet the standards of the Clean Water Act and requires Washington State to establish Total Maximum Daily Loads (TMDLs) of discharge into the river. However, most of the land in the watershed is private cropland whose owners have senior irrigation water rights. Therefore, it is extremely difficult for Ecology to monitor all activity affecting the river. This irrigation, combined with grazing livestock and sedimentation from forest roads, causes unmitigated runoff and poses an ongoing threat to salmon populations and overall ecosystem health.

While water levels are declining, and water is not legally available, Ecology has not closed the watershed to new appropriations. However, Ecology has stated that new water appropriation is unlikely without full mitigation. Despite this, the watershed and salmon populations that rely on it are in danger. There is currently no minimum flow level established for the watershed, nor any state recovery plan. New water appropriations have mostly halted, but senior rights holders are still able to take water beyond recoverable levels, and several dams along the river are detrimental to threatened salmon runs. In watersheds like this one where multiple issues intersect, establishing instream flow rules is critical. Instream flow rules in the Lower Snake River Watershed could ensure sufficient water levels and habitat for salmon runs, make the stream more resilient to pollution, and help mitigate overuse from senior water rights holders. CELP urges the Department of Ecology to follow up on its responsibility to set instream flows for WRIA 33 to ensure quality and quantity of water for critical salmon populations and local communities.