Mitigation for the Construction and Operation of Libby Dam

We compared samples collected in September 2000 (before the ULCC restoration)
with samples collected in August 2003. Three samples were collected from separate riffles
with a Surber Sampler (0.098 m 2 , 500-µm mesh), preserved in the field with ethanol and sent
to EcoAnalysts, Inc. (Moscow ID) for analysis.
We used the standard protocols for macroinvertebrate sample analysis, as outlined by
Bukantis (1998) for the Montana DEQ. These protocols use a 300-organism subsample and
genus- or species-level taxonomic determinations for all organisms. Occasionally specimen
condition or maturity prohibited taxonomy to the species level, and taxa were identified to
family or genus only.
Rapid bioassessment protocols (RBP) for Montana compare biological metrics from
study site to a population of regional reference sites located throughout the state. The original
framework was developed by Bahls et al. (1992) and modified by Bukantis (1998), Bollman
(1998), and Marshall and Kerans (2003). We used the metrics recommended by Marshall
and Kerans (2003) for the assessment of mountain streams in Montana because statistical
power analysis indicated these metrics were sensitive to environmental changes.
It is important to note that RBPs and their regional reference criteria are not scaled to
assess local-scale or reach-scale ecological changes. Furthermore, the field collection
methods used by an RBP design use different techniques and are not replicated. Therefore we
used a simple replicated statistical design to test for differences before and after restoration.
To avoid ethical problems with data-snooping, we selected the metrics prior to analysis. We
included the metrics recommended by Marshall and Kerans (2003) because they have been
successfully used in Montana mountain streams. We also used several others that have
historically been used in Montana that summarize different kinds of information. We used
these metrics because they summarize portions of the community and provide indicators of
community function.
The metrics were included Taxa Richness, EPT index (e.g., , Contribution of
Ephemeroptera, Plecoptera, and Tricoptera-taxa), Simpsons Diversity (D), the Ratio of
Baetidae: Ephemeroptera, the Contribution of Diptera, the proportional abundance of
burrowers and sprawlers (sediment tolerant), and the contribution of collector-gatherers. The
metrics were compared using two-sample t-tests. The critical level of alpha was kept at 0.05,
following the conventions of modern ecology.
The Grave Creek Phase I Restoration Project
Montana FWP entered into a cooperative agreement that was coordinated through the
Kootenai River Network to retain a consultant to develop and implement a restoration plan
for approximately 4,300 feet of channel within the lower three miles of Grave Creek (WCI
2002). Additional contributors to the project included Montana Department of
Environmental Quality, the National Fish and Wildlife Foundation, the Steele-Reese
Foundation, the U.S. Fish and Wildlife Service (Partners for Wildlife Program), the Montana
Community Foundation, the Montana Trout Foundation, and the Cadeau Foundation. The
project is termed the Grave Creek Phase I Restoration Project, and begins at the downstream
end of the Grave Creek Demonstration Project (see Dunnigan et al. 2003). Stream
restoration work began and was completed during the fall of 2002. Numerous structures
were installed including 12 rootwad composites, 11 debris jams, 8 log J-hook vanes, 4 cobble
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