Environmental activists have called on the US Army Corps of engineers to find emergency methods to prevent massive salmon die - offs in the salmon and Snake Rivers , which are being caused by contaminated water , in a bid to avoid last year 's catastrophe when high freezing temperatures killed tens of thousands of salmon returning from the Pacific Ocean . They warned that 96 % of endangered Snake River sock - eye salmon died before ever making it to the Lower Granite Dam in 2015 .
Environmental groups have called on the US Army Corps of Engineers to find emergency methods to prevent massive salmon die-offs in the Columbia and Snake Rivers, which are being caused by warming water, in a bid to avoid last year's catastrophe when high water temperatures killed hundreds of thousands of salmon returning from the Pacific Ocean. They warned that 96% of endangered Snake River sock-eye salmon died before ever making it to the Lower Granite Dam in 2015.