Sixmile Creek Fish Passage Enhancement

Sixmile Creek is located west of Missoula in the Clark Fork River watershed. Sixmile Creek is an important tributary to the Clark Fork River and has potential to increase recruitment to the Clark Fork fishery.  As part of Lolo National Forest fisheries inventories in the early 2000s, the Rose Ditch on Sixmile Creek was identified as a major source of fish entrainment.  Furthermore, the culvert crossing on the access road has been identified as a fish passage barrier and imminent failure risk.

Working with the irrigators, the Lolo National Forest and Trout Unlimited will install a Farmer’s Conservation Alliance (FCA) fish screen in the Sixmile Creek irrigation ditch and remove the culvert. The FCA screen is a horizontal fish and debris screen that has no moving parts and is self-cleaning under normal operating conditions.

The FCA screen will allow delivery of the 2.5 cfs irrigation water while returning fish and debris to the creek via a bypass pipe. Currently, large numbers of native Westslope cutthroat trout (WCT) are entrained in this irrigation canal during the summer months. Electro fishing surveys conducted by Lolo National Forest biologists documented that between 145 and 183 entrained WCT die when the canal is shut down at the end of the irrigation season, so eliminating this entrainment will increase survival of native WCT and benefit the local population.

This project is collaboration at its best.  State and federal management agencies, local resource conservation groups, private irrigators and landowners have worked together to benefit WCT and other aquatic species while meeting the needs of the irrigators. The Westslope chapter of Trout Unlimited has contributed financial support towards this project among other funders including Montana Fish Wildlife and Parks, Lolo National Forest and the US Fish and Wildlife Service,