Posted on behalf of Bill Tramp, Science teacher at Custer County District High School

7/30/2010

For the first time in over 100 years, fish are able to bypass Twelve Mile Dam and migrate upstream. When the Twelve Mile Dam was built for irrigation it blocked fish migration and during irrigation season, many downstream migrating fish were diverted into the irrigation canal and onto fields.

Thanks to the efforts of local, Roger Muggli and the US Fish and Wildlife Service among others two structures were built to help fix this problem. The first was a fish diversion that diverts downstream migrating fish around the dam and back into the Tongue instead of the irrigation canal. The second structure is a boulder filled channel that allows fish to swim around the dam and get upstream.

These projects are good models for what can be done with diversion dams like the ones on the Yellowstone at Glendive and Forsyth.