Mitigation for the Construction and Operation of Libby Dam

Figure 46. Minimal detectible difference for Taxa Richness for Libby Creek. This graph assumes
a= 0.05, and b=0.1. With three replicates, the taxa richness must increase from 33 to > 46
for the change to be statistically significant. .....................................................................113
Figure 47. Minimal detectible difference for EPT Taxa Richness for Libby Creek. This graph
assumes a= 0.05, and b=0.1. With three replicates, the EPT richness must increase from 25
to > 37 for the change to be statistically significant. .........................................................114
Figure 48. Minimal detectible difference for Taxa Richness for the Grave Creek Phase I
Restoration Project. This graph assumes a= 0.05, and b=0.1. With three replicates, the taxa
richness must increase from 33 to >41 for the change to be statistically significant.
Similarly, if 20 samples are collected each year, a change from 33 to 36 taxa becomes
statistically significant. ......................................................................................................115
Chapter 2 Figures
Figure 1. A photograph of the Eureka fishing pond taken in the spring of 2003, with the
polypropylene pond liner installed. The pond has a maximum depth is 8 feet and a toal
surface area of 0.4 acres. The pond will be stocked for recreational family fishing in the
summer of 2004. ................................................................................................................124
Figure 2. Vicinity Map for Upper Libby Creek Cleveland Project. .........................................128
Figure 3. Detailed site location map of the upper Libby Creek Cleveland Project Area. ........128
Figure 4. The top cross sectional survey of Libby Creek (#12C) was surveyed by Montana FWP
in 1999, and is typical representation of the braided channel and large amounts of
deposition within the floodplain of the upper Libby Creek Cleveland Project site. The
lower figure characterizes the design criteria used to implement project construction
activities at this site............................................................................................................129
Figure 5. The longitudinal profile of the existing stream channel prior to the implementation of
the restoration project. The survey was conducted beginning at station 0 (upper project
boundary) to approximately 2350 feet prior to the implementation of the restoration project
in the fall of 2002. The survey was not completed for the lower approximate third of the
project area. Note the lack of pool habitat within the project area...................................131
Figure 6. The longitudinal profile of the constructed stream channel thalweg in 2002 (as built)
and 2003 after the project experienced the first spring freshet. The survey begins at the
upper project boundary (station 0) and proceeds downstream to the lower project boundary
(approximate station 3200). The stream channel prior to channel construction was not
located within the same general plan view as the newly constructed stream channel.
Therefore, the existing stream channel longitudinal profile (Figure 5) could not be
superimposed on this figure due to differences in stream channel length that resulted from
an overall increase in overall channel sinuosity and length after project construction. ....132
Figure 7. The longitudinal profile for the Grave Creek Phase I Restoration Project. The survey
was completed before (2001) and after (2002; as built) project completion and after the first
spring freshet (2003). The station (longitudinal location measured at the channel thalweg)
begins at the upstream boundary of the project. ................................................................138
Figure 8. General location map of the Young Creek State Lands Restoration Project area.....141
Figure 9. Detailed location map of the Young Creek State Lands Restoration Project area....141
Figure 10. The longitudinal profile of the reach of Young Creek located within the State Lands
Restoration Project. The survey was completed before (2002; existing) and after (2003;
post-construction) project completion. The station (longitudinal location measured at the
channel thalweg) begins at the upstream boundary of the project. The as built stream
channel was approximately 250 feet longer due to the increased meander frequency that
resulted from constructing the new stream channel...........................................................143
11