Little Truckee River Fish Habitat Improvement Project
The Little Truckee River, located in Nevada County, California, is one of the most famous trout streams in the West, offering technical angling for trophy brown and rainbow trout. The Little Truckee Fish Habitat Improvement Project will enhance roughly three miles of the Little Truckee River downstream of Stampede Reservoir.
Fish numbers through the lower extent of the Little Truckee meadow are substantially lower than those of trout occupying upstream habitat due to lack of large woody debris and other instream structures. Fish creel data from the California Department of Fish and Wildlife show that catch-per-hour significantly decreases in the lower section of the river.
The lower Little Truckee River meadow is a high priority area for supplemental instream boulder structures and large woody debris, to increase cover and rearing habitat for adult and juvenile wild trout. Large woody debris and movement of large boulders -- historically present through natural recruitment -- are now limited due to Stampede Dam. Creating more places for fish to thrive will help to disperse angling pressure, protect the Little Truckee meadow and enhance the recreational fishing experience in one of California’s most popular wild trout fisheries.
Area 1: Secondary and main channel confluence
Primary goal: Enhance adult in-stream habitat
Area 1 largely lacks cover and the thalweg (deepest habitat) is narrow and limited in depth. In-stream wood structures and boulders will be introduced to encourage natural scouring, while mature willow transplants will be added to provide cover and bank erosion protection. Scour holes will be pre-excavated by large equipment to remove an armoring layer and facilitate natural scour under higher flows.
Area 2: Backwater site
Primary goal: Enhance juvenile and adult habitat
Area 2 already provides a low-velocity backwater environment over a range of flows that juvenile trout currently use. The main channel exhibits a limited deep channel with little cover. The backwater will be excavated to provide larger area for juveniles and wood will be introduced to provide some cover. Wood along the left bank will also provide scour and cover in the main channel. Exposed and submerged boulders will be introduced to the main channel.
Area 3: Steep Riffle Site
Primary goal: Adult habitat/velocity passage
Area 3 currently offers little complexity and is dominated by fast water. In-stream wood will be introduced to both banks to encourage hydraulics, scour and provide differing velocity environments. Scour holes will be pre-excavated by large equipment to remove an armoring layer and facilitate natural scour under higher flows. Transplanted willows will be placed in areas susceptible to bank scour erosion (to provide erosion protection and additional cover).
Area 4: Backwater site
Primary goal: Juvenile and adult habitat
Area 4 provides juvenile backwater habitat under a moderate range of flows and a deep thalweg along an outside bend of the main channel, but lacks cover. The backwater will be excavated, increasing habitat by 300%, to provide additional usable habitat. Wood will be used to create grade-control at the backwater entrance (to avoid capture of main channel). Wood will also be introduced to the inlet and deepest areas of the backwater to provide cover. The main channel (right bank) will be modified to include a number of habitat structures and bank erosion control (i.e., grading and transplanted willows). Wood will be placed such that they influence hydraulics over a range of flows, and submerged boulders will provide holding areas for adult trout.
Area 5: River bend
Primary goal: Adult habitat
Area 5 is similar to Area 4 such that it is characterized by a deep thalweg along an outside bend, but lacks cover. The main channel (right bank) will be modified to include a number of habitat structures and bank erosion control (i.e., grading and transplanted willows). Wood will be placed such that they influence hydraulics over a range of flows.
TU staff and the Truckee River Chapter secured Secure Rural Schools Act funding to hire Balance Hydrologic in May 2011 to complete a Preliminary Geomorphic Assessment of the Little Truckee project area. Balance Hydrologic and TU volunteers installed six monitoring sites along river to measure gauge height, data largely collected by local and regional volunteers. We then used terrestrial LIDAR (Light Detection and Ranging) along the project reach (in-kind value $10,000), which Balance used to produce an Opportunities, Constraints and Enhancement Memo and a Final Conceptual Restoration Design and Engineering Estimate for the project.
Since then, TU volunteers have logged over 1,000 hours on the river collecting data for project (in-kind value $20,000), we hired an intern to manage project for during the summer of 2011, and the California Department of Fish and Wildlife has logged pre-project fish monitoring work estimated at over $40,000, including habitat typing of the entire river.
Requisite NEPA (National Environmental Policy Act) planning for the project is underway and scheduled to be completed in summer of 2013, paid for by Trout Unlimited through another Secure Rural Schools Act grant. Project implementation is scheduled for 2014.
California Field Director