Big Timber Reconnection and Upper Lemhi Flow Improvement

Project Narrative

The project actions and deliverables were implemented as proposed, however, the timeline varied from the original proposal for both the Big Timber and Upper Lemhi Flow components as indicated below. Deviations from the original timeline were caused by delays in receiving designs, necessary design modifications, a lengthy approval process for CoE and IDWR permit applications, required revisions for environmental compliance documentation, and the need for construction postponement and re-initiation of ESA consultation for the Big Timber phase. Major construction for the Upper Lemhi Flow phase was completed in late summer/early fall 2007, with reestablishment of the Hawley/Eighteen-mile historic channel one year later in the fall of 2008, and measuring flumes installed in June 2009. The Big Timber phase experienced the majority of delays due to those issues noted above. Additional delays for the Big Timber phase included an objection to the water rights transfer made by an adjacent landowner, lengthy negotiations for a power line easement, and an administrative stalemate in approving additional engineering that was deemed necessary in order to connect the intake system with the irrigation system. Once these issues were resolved, construction moved quickly and implementation was completed in five months.There was a deviation at the Big Timer Reconnect worksite. Because the existing gauge was deemed satisfactory a new gauge was not installed.Stream dewatering due to irrigation posed a barrier to fish at the Big Timber Reconnect worksite. Completion of the project provides a seasonal reconnection during irrigation season March 15 through November 15, every year.A call for 3.5 cfs of water from a water right at the Upper Lemhi Flow Improvement worksite did not involve installation of a screen because there was an existing screen at the site.The Whitefish irrigation ditch was eliminated at the headwaters of the Lemhi River and significantly improved stream flow in the upper river. Fish passage barriers that existed in Hawley Creek, Eighteenmile Creek, and Canyon Creek were removed. All of these actions will improve spawning and rearing conditions and allow access for Chinook salmon and steelhead.The proposed project will provide a significant quantity of good quality spawning and rearing habitat that is currently unavailable to ESA listed Chinook salmon, steelhead, fluvial bull trout, and other non-listed salmonids. It will also improve the existing habitat condition in the Lemhi River. Fifty-six stream miles in Big Timber Creek will be connected to the Lemhi River throughout the year. Additional flow will be provided in the upper Lemhi River where the majority of Chinook salmon spawn and rear. As a result, three viability criteria: abundance, distribution, and productivity critical for fish to persist in the Lemhi sub-basin will be improved.