Trinity River
The Trinity River begins in the rugged Trinity Alps in northwestern California. On its journey, it tumbles through steep canyons and meanders through broad valleys until it joins with the Klamath River to flow into the Pacific Ocean. This powerful river once supported large populations of fall- and spring-run chinook salmon, as well as smaller runs of coho salmon and steelhead. Floods, as predictable as the salmon, refreshed spawning gravels, scoured deep holes and provided clear, cool water. Today, as for thousands of years, the Hoopa and Yurok tribes use the fish, plants and animals in and along the Trinity River for subsistence, cultural, ceremonial and commercial purposes.
In 1958, a plan was developed to increase water supplies and generate power for California’s Central Valley in part by transferring water from the Trinity River into the Sacramento River. Completed in 1964 for these socially and economically important purposes, the Trinity River Division of the Central Valley Project (TRD) began a decades-long era wherein up to 75-90% of the inflow to Trinity Lake was exported from the river each year.
The impacts of land use and dams combined to push the river past its regenerative capacity. By 1970, less than 10 years after the dams were completed, the extent of habitat alteration and decline in salmon and steelhead populations became obvious. Intent on reversing the decline, the U.S. Fish and Wildlife Service, Hoopa Valley Tribe and other agencies began studies that culminated in the Trinity River Flow Evaluation Study. Completed in June 1999, this study is the foundation of the Trinity River Restoration Program which is designed to restore naturally-spawning populations of salmon and steelhead to near pre-dam levels.
Overview
The Trinity and Klamath Rivers in northern California once teemed with bountiful runs of salmon and steelhead. Historically, hundreds of thousands of salmon and steelhead would enter the Klamath estuary and migrate upstream during several months of the year. Today's runs are much smaller, and are primarily fish of hatchery origin.
Both then and now, after traveling through the lower 44 miles of the Klamath River, many of these fish turned south at the confluence of the Trinity River and continue their journey to the middle and upper Trinity River. Adult salmon and steelhead spawned in the clean gravels of the mainstem Trinity and several of its tributaries. Millions of young salmonids would then emerge from the gravel between January and June and rear in the diversity of habitats found in the river. The young of some species would begin their downstream migration to the Pacific Ocean within a few months of emerging from the gravel where they were spawned. Others remained in the river for a year or more before beginning their downstream migration. Since construction of the dams, hatchery operations have substituted for these phases of the life cycle. All of these fish grew as they moved downstream through the Trinity, lower Klamath Rivers and Klamath estuary, undergoing physiological changes in preparation for life in the ocean. Suitable habitat and water quality were critical for the young salmon and steelhead during every stage of their outmigration in order for them to grow and become physically able to tolerate the transition to ocean life. After several years in the ocean, the fish returned to the Klamath River as adults and began the upstream migration to the Trinity River to spawn in their natal streams.
These impressive fish stocks defined the life and culture of the Hoopa Valley and Yurok Indian Tribes, and restoration of these resources is part of the federal trust obligation to ensure meaningful tribal fishing rights. The abundance of the region’s fishery resources also helped support the economy and way of life for the people of the region as a whole, and remains an important concern to commercial and sport fishing interests, as well as the growing recreation and tourism industry.