Physical Sciences and Mathematics Commons^™

Impacts Of Irrigation Development On Anadromous Fish In The Yakima River Basin, Washington, Robert L. Tuck

All Master's Theses

Prior to Euroamerican development, the Yakima River Basin was a major producer of salmon. Total runs of approximately 800,000 have declined to 3,000-5,000, or less than 1% of original run size. Three species are extinct in the basin, including summer chinook, coho, and sockeye.

Irrigation development, including the construction of unscreened diversions, the blockage of spawning and rearing habitat by reservoir dams, and the dewatering of spawning and rearing habitat, began in the mid-1800's and today totals approximately 500,000 acres. Historical records provide a wealth of information documenting irrigation development and its consequences on anadromous fish populations.