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LOWER
RED RIVER MEADOW RESTORATION PROJECT
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Aerial
view of Red River post restoration |
TerraGraphics is the Engineer of Record, Design Engineer, and Construction Engineer
for the Lower Red River Meadow Restoration Project. This project is comprised
of four separate land parcels and approximately 4.5 miles of river channel passing
through a large high mountain meadow within the South Fork Clearwater River Basin,
Idaho. The Red River Restoration Project was developed to address watershed impacts
in the meadow resulting from logging, road building, and gold mining activities.
These impacting activities altered the watershed hydrology, sediment delivery,
and wildlife and salmonid spawning habitat. Due to dredge mining and maximizing
grazing area throughout the meadow, local activities specifically dredged and
straightened the river channel and eliminated riparian vegetation. The river ecosystem
has responded in the following ways: 1) River length has been reduced, 2) River's
erosive power has increased, 3) Channel bed has downcut, 4) Meadow groundwater
table has lowered, 5) Meadow floodplain is inundated less frequently, 6) River
has less diversity of instream fish habitat (pools, riffles, overhanging banks,
woody debris, spawning gravels), and
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| Steambank
stabilization activities |
7) River's Summer water temperatures are elevated. River hydrology and hydraulics
have utilized the MIKE 11 and HEC-RAS computer models to establish dominant flow,
floodplain extent, scour/shear stresses, sediment transport, and new river channel
parameters. Sediment and discharge data have been collected from the Red River
and Sites gauges to develop dominant discharge measurements for channel sizing.
Reconstructed river planform was based on a 1936 photograph of the meadow showing
river meandering patterns, amplitudes, and frequency. Calculations were also employed
to confirm selected planform configuration. River restoration design was performed
to incorporate these new planform and hydraulic parameters. In addition, design
was based on deformable riverbanks to encourage historic meandering patterns.
Pool, riffle, and run sequences were incorporated into the river profile to encourage
fish habitat and river function. Revegetation of riparian and upland plants occurred
throughout the project.
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