Grant #284

South Euer Valley Road Improvement Project

Project Description:

The goal of the South Euer Valley Road Improvement Project is to reduce the sedimentation within the South Fork of Prosser Creek, a key tributary of the Truckee River. Restoration actions implemented will include road and drainage improvements along South Euer Valley Road; specifically replacing failed culvert systems and installing rocked low-water crossings to reduce road capture, implementing rolling dips to improve drainage and incorporating willow wattles downstream of drainage crossings to ensure sediment capture.

The project will reduce the suspended sediment load to the Truckee River by 1.83 tons/year. This is calculated as a relative percentage of the annual suspended sediment load estimates for Prosser Creek per the TMDL staff report (Amorfini & Holden 2008) and the size of the project site (30 acres) relative to the Prosser Creek sub basin (20,791 acres). The importance of this reduction is amplified by the “headwater” nature of the project site. Situated at the head of the 350-acre Euer Valley meadow complex, the degradation at the project site threatens to unravel functional portions of the system. Addressing this relatively acute site not only reduces the suspended sediment load to the Truckee River, but also protects against future increases.

TMWA Benefit:

Watershed Improvement: 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 significantly reducing erosion and sediment transfer from an active loading source to South Prosser Creek. Project components funded by other cost-share sources will help to stabilize eroding streambanks, improve aquatic habitat, enhance riparian vegetation and provide sustainable recreational use to reduce impacts on sensitive habitat areas. Prosser Creek is in the top three/four producers of excessive sedimentation (LRWQCB 2008).

Support to Rehabilitation of Local Tributary Creeks and Drainage Courses: The project will restore a 1.5 mile stretch of degraded roadway with direct connectivity to a key tributary that is a known contributor of sediment to the Truckee River. At present, failed culverted systems, poor drainage and improperly constructed roadways result in continuous erosion and high transfer of sediment loads that lead to increases in turbidity and temperature and a decrease in dissolved oxygen. The improvements proposed through this project and increased vegetative cover and density will mitigate the continued degradation of water quality. This project will improve watershed function and reduce sediment transfer to the Prosser Creek, as well as to the main stem of the Truckee River. Beneficial water quality improvements to Prosser Creek and to the main stem of the Truckee River will be realized through decreased erosion and a significant reduction in sediment transfer.

Re-Forestation and Re-Vegetation Projects: This project addresses and restores local resources and waterways that have been significantly impacted by historical logging operations. Legacy land-uses and improperly constructed road networks are considered to be high sources of excess runoff and sediment that further degrades stream and riparian habitat and has long-term effects on water quality and on the management of water impoundments, including Prosser Reservoir.

South Euer Valley Road is one such road that exhibits road capture at multiple perennial and ephemeral stream crossings. Restored hydrologic connectivity will reduce road capture and increase the amount of water that is available in stream channels and adjacent riparian/wetland habitat. This increased water availability will allow for greater retention later into the summer months and water will slowly be released in times it is needed most, particularly in the later summer and fall months and will help to increase late-season water supply in years where drought conditions are present.

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 improvements to water quality through reduction of sediments and other pollutants within the watershed. Specific tasks of the program include leading project site tours, producing interpretive signage, and publishing articles in our on-line and print newsletters. Volunteers will also support the project on TRWC’s annual Truckee River Day.