Mitigation for the Construction and Operation of Libby Dam

Chapter 2
Stream Restoration and Mitigation Projects in the Montana Portion of the
Kootenai River Basin
Abstract
A cooperative mitigation and implementation plan developed by Montana Fish,
Wildlife & Parks, the Kootenai Tribe of Idaho and the Confederated Salish and Kootenai
Tribes documents the hydropower related losses and mitigation actions attributable to the
construction and operation of Libby Dam, as called for by the Northwest Power Planning
Council’s Fish and Wildlife Program (MFWP,CSKT and KTOI 1998). A mix of mitigation
techniques is necessary to offset losses caused by dam construction and operation. In 2003,
Montana FWP implemented several projects to mitigate for a portion of the losses
attributable to the construction and operation of Libby Dam. In 2002, we began working
cooperatively with the Lincoln County Fair board to construct a community-fishing pond at
the Lincoln County Fair Grounds that will enhance angling and education opportunities for
young angler. This project was completed in 2003. We identified Libby, Grave and Young
creeks as high priority streams for restoration activities based on habitat quality, fish
community composition, and native fish abundance. Libby Creek has been identified as a
core area for native redband trout and bull trout, while Grave Creek has been identified as a
core area for bull trout, and Young Creek is one of the most important westslope cutthroat
trout spawning tributaries to Koocanusa Reservoir because it represents one of the last
known genetically pure populations of westslope cutthroat trout in the US portion of the
subbasin. We adopted a phased approach for restoring Libby and Grave creeks. The Grave
Creek Phase I Restoration Project represents the third phase of restoration efforts on lower
Grave Creek, and the upper Libby Creek Restoration Project was the second restoration
project Montana FWP has implemented on Libby Creek. Project objectives for the Libby,
Grave and Young Creek restoration projects focused on restoring channel stability and
increasing the quality and quantity of trout rearing habitat. Restoration activities on the
Libby Creek Cleveland Project and the Grave Creek Phase I Project were completed in the
fall of 2002, and Young Creek State Lands Project was completed in the fall of 2003. The
monitoring program for each of these projects includes pre- and post-construction monitoring
that allows comparisons to describe changes in the physical environment as a result of these
restoration activities. Dunnigan et al. (2003) demonstrated that the Libby and Grave Creek
projects decreased the bankfull width and bank erosion and increased stream depth, substrate
mean particle size, and the quality and quantity of salmonid rearing habitat. The monitoring
results presented in this document evaluate whether these physical changes were maintained
after the first spring freshet. The Young Creek State Lands Project effectively changed the
stream channel pattern profile and dimension. These changes resulted in a narrower, deeper
channel that are likely to improve the long-term quantity and quality of rearing habitat for
native salmonids. The monitoring program for this project will allow us to assess whether
the project continues to meet our objectives through time.
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