Irrigation district not a threat to steelhead, study says

LEWISTON – An irrigation district in North Idaho isn’t jeopardizing the continued existence of threatened Snake River steelhead or adversely affecting designated critical habitat, according to a biological opinion by the National Oceanic and Atmospheric Administration fisheries division.

The agency released the opinion earlier this week on the operation of the Lewiston Orchards Irrigation District following a lawsuit last July by the Nez Perce Tribe.

The tribe had alleged that NOAA Fisheries had failed to release the study in a timely manner.

The opinion sets operational and maintenance guidelines for the district for the next 15 years. The Bureau of Reclamation owns the system of dams and diversions that is operated by the irrigation district, with the water coming from Webb and Sweetwater creeks.

The biological opinion requires a minimum stream flow below Sweetwater Creek diversion dam, which began April 1.

Barney Metz, irrigation district manager, said the minimum flow can be met most years, and that there is a drought exemption that could reduce the minimum flow one year out of 10.

The district and bureau have until 2012 to attain minimum stream flows below the Webb Creek diversion dam.

Other NOAA requirements include replacing gravel for steelhead spawning in both Sweetwater Creek and Webb Creek, monitoring stream flows, and studying the benefit of installing a fish passage at the Sweetwater Creek diversion dam.

Metz told the Lewiston Tribune that the irrigation district has worked with the tribe for the past two years to improve creek flows.

The bureau gave the irrigation district $181,000 last year to replace about half a mile of the Sweetwater Canal with an enclosed pipe that will reduce seepage and evaporation.