Coldstream Canyon – Cold Creek Streambank Stabilization

The Coldstream Canyon Restoration Project is a partnership between TRWC and California Department of Parks & Recreation. The Coldstream drainage encompasses multiple tributaries to form the main stem of Cold Creek, which flows into Donner Creek and eventually into the Truckee River, which is listed as impaired for sediment (LRWQCB, 2008). Similar to the entire Truckee River Watershed, Coldstream Canyon has a long history of human disturbance including logging, railroad construction, gravel mining, stream realignment, and urbanization.

The watershed is still impacted by the past disturbances and has been identified as a significant source of sediment loading to the Truckee River by the TMDL Report (LRWQCB 2008). Coldstream Canyon is a major contributor of suspended sediment load in the Truckee River watershed, ranging from 380 to 2,253 tons annually depending on water year and flow events.

As documented in the Truckee River TMDL (LRWQCB 2008), the Truckee River is at or above its limit to assimilate sediment and still protect aquatic life and water supply beneficial uses. Excess sediment is the primary water quality problem in the Middle Truckee watershed. Factors contributing to excessive sediment delivery to the Truckee River include heavy streambank erosion, legacy land-use impacts and urban development.

The Coldstream Canyon Restoration project is planned for construction in 2023. However, contractor bids are over the available funding.  Funding from the Truckee River Fund could close the funding gap. Significant funding for this project is already secured from the California Wildlife Conservation Board ($1,380,000) and the California Water Board ($792,000). Again, funding from TRF would close the funding gap and provide sedimentation reduction along the one-mile reach of Cold Creek including bank stabilization, floodplain creation, and revegetation.

Specific work tasks for this project, and as related to TRF funding, include Project Management, and Project Implementation. Project implementation will include grading of steep erosive streambanks, re-creation of floodplain terraces and installation of boulder weirs to maintain channel grade.

TMWA Benefit:

II. Watershed Improvements: The project will decrease sedimentation and support attainment of the 303(d) listed TMDL pollutant to Truckee River. This project also enhances watershed function and habitat within the Middle Truckee watershed by stabilizing eroding streambanks, creating floodplain terraces to reduce velocity and increase inundation longevity and significantly enhancing riparian vegetation. Coldstream is in the top three producers of excessive sedimentation (LRWQCB 2008).

V. Support to Rehabilitation of Local Tributary Creeks and Drainage Courses: The project will restore a one-mile section of degraded stream channel in a key tributary that is a known contributor of sediment to the Truckee River. This project will improve watershed function and reduce sediment transfer to the Cold Creek and to Donner Creek, as well as to the main stem of the Truckee River.

VI. Stewardship and Environmental Awareness: The project will include outreach to community members through newsletters, email updates and project site tours. Outreach will be designed to increase understanding and importance of stream and habitat restoration and reduction of sediments and other pollutants within the watershed. Volunteers will also support the project on TRWC’s annual Truckee River Day.

VII. Meet Multiple Objectives: The project meets the three objectives listed above. The project also benefits meadow, riparian, and in-stream habitat, as well as the aquatic, terrestrial and human communities who rely on healthy watersheds.

VIII. Leverage Stakeholder Assets and Participation: Stakeholder prioritization of sediment reduction associated with erosive stream bank stabilization is documented in the CCWA (TRWC 2007) and in the Truckee River TMDL (LRWQCB, 2008). This project also leverages California State funding in the amount of approximately $2 million dollars.