Walking through Lincoln, California, our group turns off of a block of family homes and steps through a small wooden gate. We come out onto a lush oak woodland threaded by a paved path and a small flowing creek. This is our final stop on a tour of Auburn Ravine - a full day beginning at the Chaparral Cataracts, where the creek spills over towering rocks, dramatically shaped by water, wind and time.
At McBean Park, the flow has settled into something gentler, smooth water flowing downstream. Despite being yards away from highway 198, all we can hear is the gurgle of the stream. As we walk along, our guide points out a break along the bank where the grasses have been scraped away. Evidence of a river otter, he tells us.
It’s December, early Winter when anadromous fish - those who split their lives between fresh and salt water - are returning home to their birth streams. As I peek my head over the bank, a parade of small, silver-gray fish swim past. I find myself giddy - though these aren’t the fish I’d hoped to see today, they are a reminder of the abundant life supported by the creek.
Nestled in the center of Lincoln is Auburn Ravine, a 34 mile stream running from Auburn to Verona where it joins the Sacramento River. In the late Fall and early Winter, it is one of several Placer county waterways that is home to a native run of the fish I was hoping to see - chinook salmon.
Central Valley Chinook salmon begin their lives in fresh water streams, growing strong enough to venture through the delta and out to the Pacific ocean. They will spend the majority of their adult lives, anywhere from two to seven years, at sea before returning to their birth waterways to spawn.
After they spawn they will die, their bodies bringing nutrients upstream from the sea and becoming critical food sources for their ecosystem’s other inhabitants, including otters, eagles, coyotes, and other species of fish.
Placer’s Chinook salmon navigate from the Sacramento river into smaller tributaries - Auburn Ravine, Dry Creek, Putah Creek, to name a few. However, the number of fish returning to our creeks is weather dependent and highly variable. Salmon need adequate depth and flow of water to travel upstream in smaller waterways. High flow years in Auburn Ravine have seen as many as 358, whereas drier years have seen as few as 11.
Despite their presence here, our chinook populations are at risk. Historically, California was home to one of the largest salmon populations in the world - according to Dr. Carson Jeffers, over two million adult chinook salmon would return to the Central Valley before colonial contact. A mere fraction of that number of fish return to the Central Valley each year, with only 99,274 adult chinook returning to the Sacramento River Basin in 2024. Sacramento River Winter-run chinook have been listed as an endangered species since 1994 and Central Valley Spring chinook were listed in 1999.
Chinook in the central valley are adapted to California’s unique and extreme hydrology, defined by periods of flood and drought. But their life strategies have been interrupted as we have reshaped our waterways through damming, and levee building.
While adult chinook salmon face threats coming upstream, juvenile salmon face their own challenges as they head towards the ocean - primarily due to loss of side channel and wetland habitat, and construction of irrigation canals.
Ninety-five percent of California wetland has been lost, largely due to levee building on rivers for flood control. Under normal hydrologic conditions, rivers flood and span out over wetland flood plains. These are prime habitats for juvenile salmon to feed and grow before making their journey to the ocean. Without this natural "nursery” salmon face increased predation as they travel through the delta to the ocean due to their smaller size.
On rivers with irrigation canals, juvenile salmon face yet another danger - being pulled into unscreened irrigation drainages. As water is diverted from the river into dug canasl for agricultural irrigation, it creates a fast-moving current. Juvenile salmon are naturally drawn to faster moving water, and follow the flow into the canals, leaving them disconnected from the ocean where they inevitably die. In a study on Auburn Ravine, over 1,700 juvenile salmon were pulled into irrigation canals this way.
Though threats to salmon loom over our waterways, restoration efforts are active and promising - primarily through dam removal, irrigation screen installation, and side channel restoration. Get involved with the Sierra Club Placer Group and our partner organizations to assist in our efforts to save Placer salmon.