Columbia River Fisheries Development Program: screening of irrigation diversions

The initial task in developing a screening program was to identify the actual need for screening of irrigation diversions. To define the problem, the CRFDP initiated watershed surveys of the mid-Columbia and Snake Rivers and their tributaries in the mid-1950's and early 1960's. The resulting sub-basin reports located and enumerated most unscreened irrigation diversions in the target watersheds. The reports described a serious problem needing corrective action. Construction began in the mid-1950's and has continued to some extent into the 1980's (Table 1).