Editorial: Dams of Auburn Ravine - partnerships, problems, potential

Editor's note: Latest in a series. As it flows 34 miles from the foothills around the town of Auburn to where it enters the Sacramento River near Verona, the creek known as Auburn Ravine is beset by no less than nine dams. In a spirit of partnership, water users and water districts along Auburn Ravine have taken important steps to reduce the dangers these dams, and other water-management structures, create for migrating salmon, steelhead and Pacific lamprey. Unfortunately, the dams still cause serious problems. There is great potential to improve most of these dams to restore Auburn Ravine to its full potential as a natural spawning stream while preserving the dams' ability to deliver water to customers. In this article, we will celebrate the partnerships, describe the remaining problems and highlight the potential. Some background, and a note of appreciation None of the nine dams were built to store large amounts of water. They were built to allow diversion of water from the creek for irrigation of the surrounding farms, orchards, ranches and pastures. Most of these dams are semi-permanent – they can be partially removed during the fall and winter. One is permanent. The water these dams divert from the creek is delivered to Auburn Ravine from other watersheds via pumps, canals and pipes operated by PG&E, Nevada Irrigation District, Placer County Water Agency (PCWA) and South Sutter Water District. That water sustains an agricultural engine that powers the economies of Placer, Nevada and Sutter counties. It also helps to keep rural residential areas green during summer and fall, which reduces wildfire risk. To appreciate the benefits of the water delivered by these agencies, consider the fact that just one, PCWA, delivers water west of Lincoln that supports 3,500 acres of agricultural production, including rice, corn, wheat and pasture grass. Similarly, the estimated average annual economic impact of salmon caught in California over the last 10 years was about $200,000,000. The salmon, steelhead and lamprey that survive to swim upstream to spawn in our rivers and creeks provide food for the entire ecosystem, including otters, eagles, raccoons, giant oak trees and even the humble blackberry. And, not to be outdone, the larval lampreys aerate the streambed and filter the water of the creek. The partnerships (let's give credit where credit is due) First, a word about partnerships. We usually think of partnerships between people or organizations, but there are also partnerships between people and the environment. For example, rice farmers along the Sacramento River are testing ways to literally grow fish food in their flooded fields in the fall and winter. As natural processes decay the rice stubble, a multitude of tiny beneficial water animals proliferate. When the fields are drained for planting, those "bugs" can be released into the river to feed young salmon as they move downstream toward the ocean. That helps the salmon grow faster and healthier than they would have otherwise and gives them a good head start for survival in the ocean. So, what has been done along Auburn Ravine? The farmers, ranchers and water districts that operate the semi-permanent dams have for many years reduced the height of those dams between mid-October and mid-April to allow adult salmon and steelhead to swim upstream in the fall, and for their offspring to easily swim downstream in the late winter and early spring. In 2011, the Nevada Irrigation District (NID) partnered with Placer County, Granite Bay Flycasters, Dry Creek Conservancy and the California Department of Water Resources to modify their Lincoln Gauging Station so it would no longer block salmon and steelhead from reaching the good spawning areas upstream from Lincoln. In the first two seasons after that project was completed, more than 200 salmon were able to reach those good spawning areas. In the 2016-17 season, more than 300 made it. As the general manager of NID, Ron Nelson, said in 2012, this project grew from a conversation he had in 2008 with Jack Sanchez, president of Save Auburn Ravine Salmon and Steelhead (SARSAS). In 2013, NID put a notch in its Hemphill diversion dam to help young salmon and steelhead find their way downstream and reduce the risk that they would be sucked into the Hemphill Canal. In 2015, a partnership of Family Water Alliance (FWA) and South Sutter Water District came to fruition with the installation of fish screens at the intake to the Pleasant Grove Canal. Every spring since, those screens have saved young salmon and steelhead from certain death in the canal and have given them a chance to continue downstream to the river and ocean. This is one of 42 similar screens FWA has installed over the last 20 years in Northern California. In 2016 and 2017, Friends of Auburn Ravine partnered with the California Department of Water Resources to analyze possible designs for three of the semi-permanent dams to improve downstream migration of young salmon and steelhead while preserving the ability to deliver water to existing and future customers. PCWA plans to study one of those dams to see if it affects young salmon as they try to move downstream each spring. In 2019, Reclamation District 1001 secured approval for a multimillion-dollar, multi-benefit project along the far downstream section of Auburn Ravine known as the Cross Canal. The project will strengthen the levee on the north side of the canal to reduce flood risk, reconfigure the floor of the canal to create better habitat for fish and wildlife, and install screens on four pumps that are presently a danger to small fish. The problems (challenging but solvable) Only one of the nine dams has screens to prevent baby salmon and steelhead from being sucked into pumps or canal intakes. All nine dams interfere with the movement of young salmon and steelhead downstream after mid-April. When the dam structures are raised in mid-April, young fish often linger in the pools behind the dams, where they are eaten by predators or killed by warming water or low oxygen. After the dams are lowered in mid-October, one of them, the Hemphill Dam, located about 2 miles east of Lincoln, still blocks about 90 percent of the adult salmon and steelhead that try to get past it to reach 6 miles of good spawning areas upstream. This is because, unlike the other semi-permanent dams, it is about eight feet high even after its height has been reduced for the fall and winter. NID plans to issue a draft Environmental Impact Report in April 2021 that will describe ways in which this fish passage problem could be fixed. The one permanent dam, the 10-foot-tall Gold Hill Dam, about 6 miles upstream from Hemphill Dam, is a year-round barrier to upstream migration. It is also a threat to fish moving downstream because the canal intake is not screened. Additionally, when fish venture out of the pool and over the top of the dam, their fall onto the concrete and rocks below either stuns or kills them. Studies are underway to determine if salmon or steelhead can swim upstream to the foot of this dam. If they are "knocking on that door," the dam should be fixed to allow them to pass. Local residents have seen salmon about a half-mile below this dam but never immediately below this dam. The potential (a practical and possible future) All the semi-permanent dams could be modified to allow better downstream passage, and screens could be installed on all pumps and canal intakes. The ability to deliver water to customers could be maintained, and thousands more young salmon and steelhead could make it to the Sacramento River and then to the ocean. If Hemphill Dam is modified to allow salmon, steelhead and Pacific lamprey to easily migrate past it to the 6 miles of good spawning areas upstream, this single action would triple the total length of spawning areas in Auburn Ravine. Over the last eight years, the annual number of adult salmon that swam up Auburn Ravine to spawn east of Lincoln has varied from around a dozen to more than 300. The average was about 89 per year. Most years, many hundreds of baby salmon can be observed swimming downstream toward the Sacramento River. Those numbers show Auburn Ravine has a persistent population of salmon that should be protected and could be significantly enhanced if the improvements described above were to be implemented. Friends of Auburn Ravine is working in partnership with other local nonprofits, our local water districts, agriculture and government agencies to try to make that happen. For information, see www.auburnravine.org. We are grateful to the agencies and organizations mentioned above and the Northern California Water Association for its assistance in gathering facts for this article.