The Trinity River Restoration Program’s twenty-fourth year brought challenges and positive steps forward with agency collaborations, channel rehabilitation on the Trinity River, watershed restoration and environmental flow management.
Implementation Branch
In 2024 the Trinity River Restoration Program Implementation Branch acquired the training and licensure to fly a drone within the Trinity River watershed to better inform restoration practices and the community through aerial imagery. Small Unmanned Aerial Systems, also known as drones, are becoming a common place and vital tool for natural resource managers across the country. Drones provide a nimble, cost effective, easy to employ tool for collecting aerial photography and an array of topographic data.
In collaboration with agency partners and local landowners, the Program’s Implementation Branch completed the first phase of a two-year channel rehabilitation project in Junction City, Ca., the Upper Conner Creek Rehabilitation site. Crews restored 9.3 acres of riparian habitat, mulched and seeded upland areas, replanted riparian zones, added channel complexity and returned much needed low-flow habitat to juvenile Trinity River salmonids. The second phase of the project, to be completed in 2025, will further enhance habitat and recreational facilities for river enthusiasts in the area.
Science Branch
The Program facilitated it’s first in-person Science Symposium since 2016 in Weaverville, CA. The four-day event covered presentations on fish populations; habitat, flow and temperature; and the physical channel form. Nineteen scientists from around the world with specialties in geomorphology, hydrology, biology, and ecology gave presentations throughout event discussing their mutual impact toward management actions with the mission of restoring anadromous populations of Chinook Salmon, Coho Salmon, and Steelhead. The presentations were recorded with the help of the California Great Basin Public Affairs team and are available by clicking to this page: Science Symposium.
In December, despite initial disagreement on changes to flow management, all 8 partners came to agreement to adjust the timing of flow thus providing the Trinity River a schedule of water releases to better match the needs of rearing juvenile salmonids for water year 2025. This includes the Program’s first ever synchronized storm pulse flow, which occurred with a Dec. 23 storm event.
In recent years, scientists across the Trinity River Restoration Program’s partnership have recognized that program actions have more than doubled production of juvenile Chinook in the Trinity River, yet those increases have not translated into larger runs of adult Chinook. Efforts in the 1990’s identified only a single limiting factor: juvenile habitat. It is now apparent that Chinook have additional limiting factors which may, or may not, be controllable by the Program. The science branch has engaged a contractor (Cramer Fish Sciences) to develop a new Limiting Factors Analysis (and to provide an independent evaluation of limiting factors). The process is underway and will examine all life stages including when Chinook are in the Klamath River, estuary, and the Pacific Ocean.
2024 Funding Sources
Allocations were received from two funds within the Bureau of Reclamation in Fiscal Year 2024 totaling 86.6% of the Program’s funding source. Additionally, the U.S. Fish and Wildlife Service provided funds for 3.1% of the total budget. Both organizations are administrators of the Trinity River Restoration Program and serve as agencies in the Department of the Interior for the United States Government. An additional 10.4% of funding came from the Infrastructure Investment and Jobs Act for the Upper Conner Creek Project.
The fiscal year 2024 budget allocations went to three primary areas as shown in Figure 4 (right).
Funding supported physical modifications to the river and the associated modeling, designing, permitting, and monitoring of physical and biological responses. Other partner agencies were funded and/or contributed in-kind services to support Trinity River Restoration Program activities. It should be noted that staff positions and agency assistance funding can shift between categories so the levels of funding in Administration, Implementation, and Science are not directly comparable between years.
Thank you to all of the staff across our partnership who have made this year so successful. Here’s to an even better 2025.
Additional Accomplishments
Watershed Grantee Funding
The Program awarded $659,900 in fiscal year 2024 to two projects within the Trinity watershed. The grantees put forward $2,056,600 in matching funds for a total conservation impact of $2,716,500. The projects selected will improve aquatic habitat by reducing fine sediment delivery, improving fish passage, and pursuing increases to tributary flows in the dry season in tributaries of the Trinity River. We congratulate the grantees and are excited to see the outcome of each project. Please read below to learn about each grantee, proposal and award amounts.
Salt Creek Floodplain Restoration Project (CA)
Grantee: Watershed Research and Training Center
Grant Amount: . . . . . . . . . . . . . . . . . . . . . $470,900
Matching Funds: . . . . . . . . . . . . . . . . . $2,026,600
Total Project Amount: . . . . . . . . . . . . $2,497,500
This project is granted to improve 2,000 feet of heavily degraded salmonid habitat along Salt Creek, a South Fork Trinity River tributary, by reconnecting the creek to its historic floodplain using engineered and process-based restoration techniques. The project will increase aquifer recharge and storage for slow release to temper a thermal barrier for salmonids, restore geomorphic functions that will improve salmonid spawning gravels, create pools for summer cool water refugia, increase habitat heterogeneity for winter flow high-velocity refugia, and improve native riparian flora, all of which will increase the resilience of aquatic species from the impacts of climate change.
Upper Hayfork Creek Assessment and Planning Project (CA)
Grantee: Watershed Research and Training Center
Grant Amount: . . . . . . . . . . . . . . . $189,000
Matching Funds: . . . . . . . . . . . . . . $30,000
Total Project Amount: . . . . . . . . . $219,000
The Upper Hayfork Creek Assessment and Planning Project will assess over 17 stream miles and 700 floodplain acres within the upper Hayfork Creek watershed, a major tributary to the South fork Trinity River in California. The project goal is to identify restoration opportunities for the purpose of improving salmonid habitat quality and quantity. The Project will utilize GIS and LiDAR analyses, field measurements of salmonid presence and habitat characterization, and a comparison of ecological flow needs with water availability. The outcome of the Project will be one Restoration Assessment and Planning document presenting analysis, field data collection, and outreach results with a priority list of restoration projects and one restoration design to advance toward implementation.
In addition to the two new watershed projects mentioned above, one project that was granted Program funding was completed in 2024. Read below for the project accomplishments.
In September last year an opportunity to complete Phase I at the Indian Creek tributary restoration project arose from budgetary savings in FY24 and was approved by the Trinity Management Council at the September quarterly meeting. While most of the project had been restored in 2021, a key upper portion of the Environmental Study Limit was omitted during restoration due to an active mining claim on BLM land. Last summer the mining claim lapsed, and the Program was presented with a narrow window to complete the stage zero project as it was originally designed. After approval to allocate excess funds to the project, the Yurok Tribe Construction Corporation made quick work of leveling the highly degraded channel as the stage 0 floodplain design intended. In addition, large wood structures were placed to encourage habitat formation.
Final Publications and Reports
Publications and Reports
Thermal Refugia and Tributary Monitoring August and September 2021
Report for the Trinity River Restoration Program (TRRP).
Martel, C. 2023. Hoopa Valley Tribal Fisheries Department, Hoopa, California.
Juvenile salmonids, such as steelhead, Chinook, and coho salmon, rely on cooler water, known as thermal refugia, to survive during warm weather and low-water conditions. In 2021, a particularly dry summer in the Trinity River basin forced these young fish to seek refuge in the lower reaches of tributaries, especially on the Hoopa Valley Indian Reservation (HVIR). This reliance highlights the importance of monitoring the health of these tributaries, as drought conditions can pose serious risks to salmon populations.
To address this concern, the Hoopa Valley Tribal Fisheries Department (HVTFD) conducted regular surveys of six tributaries on the HVIR, assessing environmental conditions to ensure the habitats remain safe for juvenile salmonids. Additionally, reports indicated that adult Chinook salmon were crowding at the mouths of these tributaries, suggesting that high temperatures in the mainstem Trinity River were preventing their migration into cooler areas. Monitoring efforts are crucial for documenting and addressing any negative impacts on salmon populations.
Juvenile Survival and Migration Rate Study
Report for the Trinity River Restoration Program (TRRP).
Hoopa Valley Tribal Fisheries Department (HVTFD). 2023. HVTFD, Hoopa, California.
Juvenile Chinook salmon in the Trinity River tend to experience cooler temperatures and migrate later than other populations in the Klamath Basin. This delayed migration can put them at risk as they navigate through the warmer, inhospitable conditions of the lower Klamath River, which has higher disease levels. There is limited information available about how well these out-migrating fish survive as they travel from the upper Trinity River through the lower Klamath.
To better understand their survival and migration patterns, the Hoopa Valley Tribal Fisheries Department utilized juvenile salmonid acoustic tags (JSATs) in Spring 2022. These tags are designed to track juvenile salmonids as they move through river systems. Each tag emits a unique code at specified intervals, allowing researchers to monitor individual fish using submerged acoustic receivers. An array of receivers was set up along the Trinity and Klamath rivers to collect data on tagged natural and hatchery fish released near Pear Tree Gulch, facilitating the measurement of survival rates, migration speeds, and pathways taken by these juvenile salmonids.
A Method for Scheduling Lewiston Dam Releases to Mimic Diel Variations in Flow on Unregulated Streams
Report for the Trinity River Restoration Program (TRRP).
Buxton, T. H. 2024. TRRP, Weaverville, California.
Diel oscillations refer to the regular, periodic fluctuations that occur over a 24-hour cycle in environmental conditions, such as temperature or water discharge in streams and rivers. In streams, these oscillations can have different causes depending on the season. In winter, they often result from the melting of snow during the day, which affects how water moves through the soil and streams. From spring to fall, variations are influenced by evaporation and solar radiation. During the day, evapotranspiration can draw groundwater up to the soil surface, while at night, water in the vadose zone shifts back downslope. Additionally, evapotranspiration may tap directly into groundwater reserves during the day, with replenishment occurring at night through interactions between the stream bed and surrounding soil. Understanding these diel oscillations is crucial for comprehending ecological processes and the behavior of aquatic organisms.
Mapping Active and Exposed Coarse Bars and Fine Sediment Deposits in the Restoration Reach of the Trinity River, California
Report for the Trinity River Restoration Program (TRRP).
Buxton, T. H. and J. McSloy. 2024. TRRP, Weaverville, California.
In summer 2023, a mapping study of coarse and fine sediment deposits was conducted on the Trinity River, specifically between Lewiston Dam and the North Fork Trinity River. The study identified a notable deficit of fine sediment, particularly upstream, demonstrating insufficient fine deposits extending up to near Steiner Flat. In contrast, coarse bar areas showed significant growth, increasing by 45% from about 1.34 million square feet in 2014 to nearly 1.96 million square feet in 2023, alongside a 30% rise in the number of bars. This growth suggests that sediment management efforts, such as gravel augmentation, can effectively mimic natural sediment supply to the river.
Coarse bars were primarily found in areas of channel expansion, bends, and reconstruction projects, while fine sediment deposits were linked to similar factors, with vegetation playing an important role as well. The primary limitation on the accumulation of fine sediment appears to be the lack of supply from Lewiston Dam downstream. To address this deficit, the addition of fine sediment near the dam and increasing channel complexity could create more suitable environments for sediment deposition. Furthermore, introducing large wood and enhancing channel roughness could facilitate the development of both fine and coarse bars.
Trinity River Restoration Program Objectives and Targets Summary
Trinity River Restoration Program (TRRP). 2024. TRRP, Weaverville, California.
The finalized Objectives and Targets document, approved by the Trinity Management Council in 2022, outlines refined ecological goals for the Trinity River Restoration Program (TRRP). The need for this update arose from the limitations of the Integrated Assessment Plan completed over a decade ago, which encouraged the need for a more organized and streamlined set of objectives. Starting with a workshop in 2013, the process faced delays but regained momentum after the TRRP Interdisciplinary Team provided new guidance in 2018.
In early 2021, the Fish, Flow, Physical, and Riparian and Aquatic Ecology technical workgroups presented their recommendations for new objectives and targets. This document summarizes their efforts, detailing how the previous objectives were assessed and the new ones developed. While some objectives are still conceptual and pending completion, the document aims to serve as a living resource that will be updated as progress is made. It is structured into five sections: four report on each workgroup’s recommendations, and the final section outlines the next steps for prioritizing, updating, and addressing outstanding questions regarding the objectives and targets.
Environmental Reports and Findings
Sediment and Wood Augmentation along the Trinity River Restoration Reach Environmental Assessment and Initial Study
U.S. Bureau of Reclamation Trinity River Restoration Program (USBR-TRRP), North Coast Regional Water Quality Control Board, and U.S. Bureau of Land Management (USBLM). 2024. July, 2024.
DOI-BLM-CA-2023-0033-EA, CGB-EA-2022-028, California State Clearinghouse No. 2008032110. USBR-TRRP, Weaverville, California.
Available: https://www.trrp.net/library/document?id=2652
The Trinity River Sediment and Wood Augmentation Project aims to enhance the river’s health by creating better habitats for salmon and steelhead fish. Developed by the U.S. Department of the Interior and its partners, the project involves strategically placing sediment and wood in the river to support spawning and rearing habitats. This initiative is informed by previous environmental assessments and recommendations established in 2011.
The project complies with the National Environmental Policy Act (NEPA) and the California Environmental Quality Act (CEQA) to carefully evaluate its potential environmental impacts. The Trinity River Restoration Program (TRRP) will implement sediment placement at five key locations to improve the river’s ecosystem, ensuring it remains a vital resource for biodiversity and future generations.
Trinity River Variable Flow Project Environmental Assessment
Project Proponent and Lead Agency U.S. Department of the Interior Bureau of Reclamation – Trinity River Restoration Program. 2024. December 2024. CGB-ED-2024-047. USBR-TRRP, Weaverville, California.
Available: https://www.usbr.gov/mp/nepa/nepa_project_details.php?Project_ID=55082
The Trinity River Restoration Program plans to adjust water releases from Lewiston Dam to benefit salmon and steelhead fish during the winter and spring months. By shifting the timing of these releases while staying within authorized water volumes, the program aims to replicate natural river flow conditions more closely. This adjustment will help create habitats for young fish, improve conditions for their growth, and support earlier migration by providing necessary food sources and favorable environmental conditions.
The modified flows will occur in two key periods: the Flow Synchronization Period and the Elevated Baseflow Period. These changes are designed to enhance the river ecosystem by flooding rearing habitats before and during the emergence of fry, reducing cold water impacts in spring and early summer, and promoting the availability of food for juvenile fish. This project was previously recorded under tracking number CGB-EA-2024-011.
Environmental Reports and Findings
East Weaver Creek Dam Intake Relocation & Dam Removal Project & McKnight Ditch Water Conservation Project
Report for the Trinity River Restoration Program (TRRP). 5Cs, Weaverville, California.
Five Counties Salmonid Conservation Program (5Cs). 2024.
A Trinity River Restoration Program watershed grant helped fund two important projects to restore salmon habitats in the East Weaver Creek area. These projects returned over 2 cubic feet per second of water to flow back into it. These projects improved habitat conditions for salmonids in more than 3 miles of the creek downstream from East Weaver Creek Dam and will also reconnect 2.5 miles of habitat upstream that had been blocked.