An NID Watershed Improvement Project
In 2010, residents and fishermen in Lincoln, Placer County, witnessed a phenomenon not seen in years. At least 30 fall run Chinook salmon were counted in Auburn Ravine Creek inside Lincoln city limits.
Several small modifications to downstream irrigation water diversion points in Sutter and Placer counties had allowed the salmon to migrate from the Central Valley as high as Lincoln (elev. 167 ft.). However, continued migration of the fish to higher spawning grounds was hampered by a growing waterfall, caused by tail water erosion below a water measurement station.
The station is owned and operated by the Grass Valley, Nevada County-based Nevada Irrigation District (NID) and has been used since 1981 to chart water flows from NID to other nearby agencies.
Soon the possibility of bringing more natural conditions back to Auburn Ravine came into wider public focus. The fish passage concept had originated a few years earlier when the Auburn Ravine-Coon Creek Restoration Plan was adopted as part of the Placer County Conservation Plan.
Through a series of meetings, NID and Placer County worked out preliminary details of a project that would allow fish migration at any flow level over and through the six-foot barrier at the water measurement station and the eroded creek bed below it. The goal was to bring a more natural condition to Auburn Ravine.
The collaborative effort would become known the Auburn Ravine Fish Passage Project. The project drew wide industry and community support. Placer County secured a CALFED grant that would fund part of the project, NID took the role of lead agency and pledged further funding. Soon the Dry Creek Conservancy and Granite Bay Flycasters were on board with additional funds.
Project planning and environmental studies were completed in early 2011 and construction was scheduled for the fall of 2011. Needed water deliveries and the potential for early fall storms left a narrow window for streambed construction so a very tight construction schedule was developed.
Another construction concern was that the project, located in the Lincoln Crossing Nature Preserve, is surrounded by homes and used by residents for walks and outdoor enjoyment. NID addressed issues of access, noise, dust and safety to the satisfaction of neighbors.
Construction was scheduled for Oct. 1-Nov. 30, 2011 and Sacramento contractor Preston Pipelines, Inc. was brought on board to do the job. Complexities in stream construction led to a lengthy and detailed state and federal permitting process, with final permitting obtained just in time.
During the narrow two-month construction window, a temporary bypass was constructed to dry the creek bed while continuing the required downstream flows. “There are risks involved in creek bed construction at this time of year,” said NID Project Engineer Keane Sommers. “We were very concerned about rainwater coming down the creek and flooding our construction site so we oversized the bypass.”
Once the bypass was in place, 200 feet of the overgrown, eroded creek channel was cleared and tapered back to a more natural form. A “nature-like fish way” with a series of rock chutes and step pools was sculpted into the streambed. Concrete cutoff walls designed to stem erosion were buried up to 13 feet into the channel and stabilized by large rock and smaller materials. Native plants were added to the newly-reconfigured steam banks. Surrounding areas were restored to pre-construction conditions. NID agreed to monitor the site for five years to ensure that the grasses and 125 trees that were planted provide a suitable riparian habitat.
The project received accolades from nearby residents as well as from fishing and environmental advocates who are enthusiastic about opening an additional mile of Auburn Ravine to fish movement. Upstream, in Auburn, city officials viewed the project as an initial step in a long term vision of opening Auburn Ravine all the way to their city.
“Watershed stewardship is an important part of our mission,” said former NID General Manager Ron Nelson, who spearheaded the project. “We have a watershed improvement fund and this was a community effort that fit our mission well.”
NID contributed in excess of $500,000, CALFED $304,000, Placer County $50,000, Bella Vista Foundation $55,000, and Granite Bay Flycasters $10,000.
By January 2013, in the first full fall migration season, more than 270 salmon had been counted in the one-mile stretch of Auburn Ravine above the NID fish passage project.