In 2010, the Spread Creek dam, an obsolete, crumbling diversion dam for irrigation located just outside of Grand Teton National Park on Bridger-Teton National Forest lands  near Jackson Hole, WY, was removed through a partnership effort, opening up over 50 miles of Spread Creek to migratory Snake River cutthroat trout for the first time in over 50 years.

As a result of the previous project phase, Spread Creek is now connected to the Snake River system in terms of fish migration, and a modernized diversion structure requiring less annual and seasonal disturbances to the Spread Creek riparian area allows water users the ability to divert irrigation water while maintaining fish passage throughout the year.

Post-dam removal monitoring by project partners has documented the successful movement of migratory cutthroat trout throughout the Spread Creek drainage and through the former dam site. However, it has also illustrated the need for a fish screen on the Spread Creek irrigation system’s ditches, as many juvenile and adult cutthroat trout and other native fish species like bluehead suckers (a WY Species of Greatest Conservation Need) are being swept into the ditches when trying to out-migrate throughout the year. In addition, flooding has damaged the diversion structure’s rock weirs, leading to significant issues with water delivery and channel scouring, and associated sedimentation and extreme bank instability that continues to threaten water quality and habitat in the area, especially in high water years.

The second and final phase of the Spread Creek Fish Passage Project will ensure unimpeded migration between the Snake River and Spread Creek by installing a fish screen that prevents losses of native fish and by stabilizing, improving, and protecting the diversion and adjacent stream channel. It will accomplish this by: 1) installing a fish screen that will eliminate fish entrainment in ditches; 2) rehabilitating the diversion structure for long-term stability and improved fish passage; and 3) adding instream structures to protect banks, channel, and irrigation infrastructure within the project area. It will be true win-win-win for native fish, ranchers, land managers, and the public that recreates in the area. Hydrologic benefits include improved water quality, streambank stability, and native fish habitat and passage. The project will provide a good example of green, fish-friendly irrigation infrastructure in the area.

*Project removes artificial barriers that restrict passage and/or natural flow of water for some period of the year