Truckee River Yacht Club, Rocks in the River,
Truckee River Restoration Project, Reno, Nevada
With the goal of enhancing fish habitat
and aesthetics within the Truckee River, H&C, Inc. examined the potential
effects of boulder emplacement within the section of the stream channel between
the Sierra Street and Virginia Street bridges, adjacent to the Reno City
Redevelopment Truckee River walk. Fish habitat was poor because this section of
the Truckee River flowed fairly uniformly through the 125-foot stretch, without
the boulder pools and eddies needed to produce variability. During high flow
periods, few pools and eddies existed for fish to rest and feed and during low
flow periods, shallow water warmed and failed to hold the oxygen necessary for
fish survival.
H&C, Inc. used the HEC-2 analysis to model
pre- and post-project river flood profiles to determine potential flooding due
to "random" boulder placement versus the creation of riffle pools. The
HEC-2 analysis showed that the creation of riffle pools would increase the
100-year flood stage by 0.19 feet more than random boulder placement. H&C,
Inc. recommended that 10 to 15 boulders be placed randomly in the deepest part
of the stream channel (the "thalweg") in an S-shaped pattern and/or in
small groups. The design would enable pool formation and variability, maximize
the creation of fish habitat by avoiding pool overlap, potentially decrease
water temperature, and create a more natural and aesthetic river scene. As a
result of our recommendations, scour pools have been created increasing a
healthy fish habitat within the downtown Truckee River corridor.