Perazzo Canyon Creek were deeply entrenched and over-widened through the meadow. Both streams appeared to have been diverted during dairy operations in the early 1900s. The streams accessed the floodplains only once every five to ten years; a natural recurrence interval for overbank flow should be every one to two years. Stream surveys showed that many streambanks within the project area were highly unstable and most reaches had a much higher width-to-depth ratio than is natural or desirable.. The high width-to-depth ratio means that during low flow months, the streams were very shallow and water temperature exceeded critical levels for aquatic life.Prior to restoration, the Little Truckee River and
When completed, the project will halt the human-caused degradation in the geomorphic and hydrologic functions and thus restore the health of the riparian and aquatic habitat by:
- Increasing floodplain access, which re-waters the meadow surface and improves adjoining wetland habitat;
- Increasing capacity for water infiltration in the meadows by restoring the cut banks on the actively eroding channels;
- Moving flows to a stable, well vegetated channel which eliminates the currently eroding banks and decreases sediment supply;
- Moving flows across the meadow surface to filter out sediment and other materials and decrease sediment supply;
- Decreasing water temperature in the late season by returning the flows to a narrow, well vegetated channel;
- Decreasing sediment deposition by rebuilding alluvial fan function.
Restoration of Phases 1 and 2 are completed. Vegetation, surface water and ground water monitoring are continuing and the data will be used to finalize the restoration design of the remaining sites.
The Truckee River Watershed Council in partnership with the U.S. Forest Service – Tahoe National Forest, Sierraville District completed a geomorphic assessment of the Perazzo Meadows watershed (Swanson Hydrology and Geomorphology, 2008 link) and developed a restoration plan. NEPA, CEQA, and all environmental permits are completed.
Funding for this project comes from (listed in alphabetical order):
- American Reinvestment and Recovery Act
- California State Water Resources Control Board
- Donors of the Truckee River Watershed Council
- U.S.F.S. Tahoe National Forest