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Watershed and Fisheries Ecological Restoration on the Six Rivers National Forest

Restoring healthy and resilient watersheds and fisheries habitat...

New: Water Quality Monitoring and Reporting Program Annual Report – August 2016 (Waiver No. R1-2015-0021)

This annual report is submitted to the North Coast Regional Water Quality Control Board each summer to disclose the prior field season monitoring efforts. The annual report focuses on efforts associated with water quality monitoring. One example is the Best Management Practice Effective Program (BMPEP) monitoring, which requires random assessment of sites in regard to potential erosion and sedimentation. The annual report also discloses estimated cubic yards of sediment prevented from potentially delivering to a waterbody due to road maintenance work and landslide removal along Forest Service roads.

Six River Aquatic Restoration Project

The Six Rivers National Forest is in the early stages of developing a project to restore aquatic habitats in selected stream reaches across the forest. The overall purpose of the restoration project is to improve riparian and instream conditions for anadromous fisheries including listed threatened and sensitive fisheries and their critical habitats. The forest is considering a suite of potential restoration actions including adding large woody debris to provide cover for juvenile coho salmon, and developing side-channel areas for winter rearing and riparian treatments to encourage species diversity.

See below for more information and maps related to past watershed and fisheries restoration efforts.


Restoration has long been a central focus of the watershed and fisheries management programs in the Six Rivers National Forest (Forest). As the name implies, the Six Rivers (Smith, Klamath, Trinity, Mad, Van Duzen and Eel) has an extensive network of streams that have a diverse array of fish habitats for salmon and steelhead. With over 400 miles of anadromous fish habitat within the forest boundary, the Forest manages some of the most significant and valuable salmon and steelhead habitat on the West Coast.


Multiple flood events, but most notable the 1964 flood, had major effects on many of the watersheds within the Forest including tributaries to the Klamath and Trinity Rivers such as Bluff, Red Cap, Horse Linto, and Willow Creek watersheds and other larger watersheds such as the Salmon, South Fork Trinity River and Mad River watersheds. These flood events, combined with past land management activities and naturally occurring landslides, resulted in many failed road systems which altered stream channels and riparian areas and negatively impacted spawning and rearing habitat in many watersheds throughout the Forest. These factors, in combination with ocean and river harvests, hydropower and hatcheries, have had dramatic impacts on anadromous fisheries. Almost all native anadromous fish stocks have declined in the North coast and inland watersheds. The Smith, Klamath, Trinity, Salmon, Mad, Van Duzen and Eel river drainages provide spawning and rearing habitat for coho salmon, listed as threatened under the ESA with the latter three also providing habitat for two additional ESA listed populations (Northern California steelhead and California Coastal Chinook). State (2005) and draft Federal (2012) Coho Recovery Plans have described types and locations of restoration actions specific to Forest watersheds that are necessary to improve in-stream habitat for Coho salmon recovery. Stream inventories have indicated a need to improve over winter rearing habitat and increase channel cover and complexity in selected stream reaches on the Forest.

Recognizing the declines in watershed condition and fish habitat quality, Forest Service fisheries biologists and hydrologists initiated in-stream and hillslope inventories in the 1980s and 1990s with the goal of identifying what factors were responsible for the degraded conditions and what actions might be taken to “jump-start” watershed recovery. These watershed and fisheries restoration efforts fall into two categories: 1) Instream Habitat Restoration and 2) Watershed Hillslope Improvements.

Watershed and fisheries restoration work accelerated in the 1990s associated with the Northwest Forest Plan. Beginning around 2000, with the recognition of the need for more resilient watersheds and the challenges associated with climate change, watershed and fisheries restoration efforts were expanded to include outside partnerships with Karuk, Yurok and Hoopa Tribes, as well as partnerships with agencies such as California Department of Fish and Wildlife, National Marine Fisheries Service, California Department of Parks and Recreation, and North Coast Water Quality Control Board. The Six Rivers Watershed Restoration Program has garnered over 10 million dollars in partnerships and grants to implement priority restoration treatments in key and priority watersheds. To date, the Six Rivers Watershed Restoration Program has inventoried and assessed watershed risk on 90 percent of the forest roads (2600 miles out of a total of 2850 miles on SRNF), decommissioned 462 mi of road and storm-proofed 197 miles of roads, and treated over 400 landslides. The instream restoration work, road decommissioning efforts and landslide treatment accomplishments of these multimillion dollar restoration partnership efforts are illustrated in the following maps:

A more detailed Restoration History was completed for the following watersheds: Middle Fork Smith River (link), South Fork Smith River (link), Bluff Creek (link), Horse Linto Creek, Cedar Creek (link), and South Fork Trinity River (link).

Watershed and fisheries restoration work is continuing in many watersheds throughout the Forest and is in various stages of development, ranging from field inventories, planning (NEPA) through to grant writing and implementation (Current Watershed and Fisheries Restoration Projects and Partnerships)

Instream Habitat Restoration

The habitat of many of the anadromous reaches was simplified by the 1964 flood. In the decades after the flood, anadromous fish-bearing streams were inventoried to determine if spawning and rearing habitats were limiting factors for robust fisheries. The 1980s through 1990s had an active in-stream restoration program designed to create diversity of habitat by placing boulders and large wood in the streams to provide cover and complexity (see photographs 1 and 2). Instream structures designed to improve rearing and spawning habitat were placed in a number of streams on the Forest (View Watershed & Fisheries Restoration Maps). The majority of instream fisheries enhancement structures were implemented on tributaries to the Middle and South Fork of the Smith River, Willow and Horse Linto Creeks on the Trinity River, and Bluff and Red Cap Creeks on the Klamath.

In addition to instream structures, several small scale hatcheries using wild, native stock were operated in Red Cap, Camp, and Horse Linto Creeks. The Horse Linto facility had the longest tenure of the three, operating from 1985 through 1994. These facilities are no longer in operation.

In addition to the legacy of simplified fish habitats from storms, many stream reaches also lost conifers from many riparian areas along key fish habitats leaving the riparian areas dominated by alders, thereby impacting future and long-term woody debris recruitment.

In many stream reaches, limiting factors may be impacting short and long term species recovery. Limiting factors include maintaining riparian process and function such as long-term channel shade, cover, and complexity through large woody debris recruitment (LWD) and riparian treatments to encourage species diversity. In order to facilitate LWD recruitment, riparian areas in anadromous reaches that are dominated by mature alders may need to be selectively treated to accelerate successional stand growth similar to conditions prior to the 1964 flood. In addition, instream reaches that have a need for increase channel complexity and over- winter rearing habitat may need new construction and or/maintenance of side channel rearing ponds, repair/enhancement of prior stream structures and access of heavy equipment to these areas.

In the late 1990s, an increased recognition of road culverts creating fish migration barriers and limiting access to historical ranges resulted in surveys to determine fish passage barriers across the forest. On the Six Rivers National Forest, the majority of culvert barriers to anadromous fish were identified along county roads and highways. A few anadromous fish passage barriers on forest service system roads were identified and corrected on Merrill, Ti and Griffin Creeks through partnerships with the 5 Counties Salmonid Restoration Group, Karuk Tribe and California Department of Fish and Wildlife grants (see photographs 3 and 4 of fish passage restoration efforts on Ti Creek).

More information on instream fish habitat improvement treatments are described in the watershed restoration histories for selected watersheds such as Middle Fork Smith River (pending), South Fork Smith River (pending), Bluff Creek (pending), Horse Linto Creek, Cedar Creek (pending), and South Fork Trinity River (pending).

Rock Weir Hurdygurdy Photo 1 - Rock weir on Hurdygurdy Creek.
Photo 2 Boulder placement on Hurdygurdy Creek, 1981. Photo 2 - Boulder placement on Hurdygurdy Creek.
Photo 3 Culvert barrier to fish passage on Ti Creek – pre- treatment. Photo 3 - Culvert barrier to fish passage on Ti Creek – pre- treatment.
Photo 4. Post-treatment of culvert correcting fish barrier on Ti Creek. Photo 4 - Post-treatment of culvert correcting fish barrier on Ti Creek.

Watershed Hillslope Improvements – Roads and Landslide Inventories and Treatments

Watersheds within the Forest are characterized by steep and incised drainages and many of those watersheds have a natural susceptibility to landslides, particularly associated with high intensity storms and earthquakes. All watersheds across the Forest are listed as water quality impaired under the Clean Water Act, except for the Smith River watershed. The majority of water quality impairments are from detrimental levels of sedimentation and turbidity attributable to roads and road failures, but some watersheds also include temperature impairment. Past land management activities (e.g. road construction and timber harvest) combined with large storm events have resulted in sedimentation of many streams throughout the Forest. These sedimentation levels are gradually improving, as are in-stream habitats.

More information on roads and slides treatments are described in the watershed restoration histories for selected watersheds such as Middle Fork Smith River (pending), South Fork Smith River (pending), Bluff Creek (pending), Horse Linto Creek, Cedar Creek (pending), and South Fork Trinity River (pending).


In the Forest, roads are the leading source of management-related sediment inputs, predominantly associated with mass wasting features such as shallow debris slides and debris torrents. The majority of road-related erosion and sediment delivery are associated with large storm events that trigger culvert failures, stream diversions, and mass wasting such as debris slides and smaller slumps within the roadbed. With declining road maintenance funding, the risk of road failures and elevated sediment delivery increases, particularly in the event of future large storms.

Roads have the potential to substantially affect water quality and watershed condition through accelerating erosion and sedimentation (i.e. gullies, landslides), by altering channel widths and depths, and by changing the runoff characteristics of watersheds. These changes result in detrimental impacts to fish habitat, which in turn impact the viability of fisheries. Reducing adverse impacts caused by roads on watershed processes can be accomplished through road restoration activities such as road improvements (i.e. stormproofing) as well as road decommissioning (see photographs 5, 6 and 7). Storm-proofing measures include upgrading culvert sizes so that road stream crossings are less likely to fail during large storm events. Storm-proofing measures also include correcting stream channel diversion potential so that when culverts plug or fail during large storm events, the stream does not divert down the road and cause offsite erosion and sedimentation as shown in photograph 8. Road decommissioning involves the restoration the natural drainage of the hillslope and frequently involves the removal of culverts and recontouring of the stream crossing to mimic natural drainage.

The primary objective of road restoration is to minimize future erosion and mass wasting such as landslides through removing culverts and out-sloping (restoring the natural drainage pattern). Excavating fill from stream crossings and removing culverts is one of the most cost-effective treatments available for reducing sediment input into streams. Removing a drainage structure that is no longer maintained (and/or is failing) by excavating the road fill can prevent major fluvial erosion and/or landslides from developing, with potentially significant consequences to beneficial uses. Excavation of fill from stream crossings returns streams to more naturally functioning hydrologic systems.

Photo 5: Steinacher Road decommissioning – Salmon River Photo 5 - Steinacher Road decommissioning - Salmon River
Photo 6 Stream crossing restoration on decommissioned road 12N29 - Irving Creek. Photo 6 - Stream crossing restoration on decommissioned road 12N29 - Irving Creek.
Road decommissioning and stream crossing restoration on road 12N08 through partnership with Karuk Photo 7 - Road decommissioning and stream crossing restoration on road 12N08 through partnership with Karuk Tribe.
Photo 8 – Stream diversion from plugged culvert on abandoned road. Photo 8 - Stream diversion due to plugged culvert.

Landslide Inventories and Treatments

Periodic incidences of landsliding are an inherent characteristic of watersheds in northern California, particularly during storm events. Landslides are the dominant mechanism of sediment delivery on the Forest. The combination of large storms, locations of roads on unstable or erodible terrain and limited road maintenance funding have contributed to incidences of management-related landsliding and mass wasting; nevertheless, the majority of mass wasting is an inherent and natural hazard on most lands on the Forest, regardless of management. Since the 1970's, the incidences of management-related landsliding and sediment delivery have declined, in large part due to more stringent forest practice rules, improved road design practices, implementation of Best Management Practices and significantly fewer new roads being built.

Beginning in the late 1980s selected landslides in key fisheries streams were assessed and stabilized to reduce chronic sedimentation of instream habitat. As a result of those early successes, a forest-wide inventory of all landslides on the Forest was conducted to identify locations of active landslides, trends over time, probable cause of landslide (natural or management-related) and treatment potential. Findings of this effort revealed that approximately one-third of active landslides are associated with roads and landings, and that the incidences of road-related landslides have significantly declined. Approximately 10,000 landslides were identified on lands within the Forest and 400 landslides were considered treatable, given the limitations associated with access, slope steepness, and active or ongoing instability (see map for locations of treated landslides). Methods to stabilize and reduce sediment delivery included revegetation (afforestation) with native tree and shrub species (photographs 9 and 10), heavy equipment (excavators, bulldozers, dump trucks), and installation of sediment traps or catchment basins. More information on the success of the afforestation effort of landslides on Forest is shown in the Power Point (5mb pdf).

Photo 9 - CCC's planting native vegetation Craigs Creek Photo 9 - CCC's planting native vegetation Craigs Creek
Photo 10 Landslide planting on tributary to Grouse Creek. Photo 10 - Landslide planting on tributary to Grouse Creek.

Current Watershed and Fisheries Restoration Projects and Partnerships

The need for continued restoration efforts to improve water quality and fish habitats for threatened and endangered species are clearly emphasized in both Forest Service policy and guidance as well as in multiple regulatory direction described in Total Maximum Daily Load Plans (TMDLs), Water Quality Waiver Terms and Conditions, and state and federal recovery plans for coho salmon (Federal Coho Salmon Recovery Plan pending). The Forest Service recently initiated the Watershed Condition Framework  as a means of improving watershed condition. As part of this framework, Bluff Creek and Upper Mad River are two watersheds that have been identified as Priority Watersheds for restoration treatments. Watershed Restoration Action Plans (WRAPS) have been developed for these watersheds.

In addition to restoration efforts in Priority Watersheds, other watershed and fisheries restoration planning and implementation efforts are currently under way in other areas of the Forest.

  • As a result of partnerships with the Karuk, Hoopa, and Yurok Tribes, California Department of Fish and Wildlife, NMFS, California Department of Parks and Recreation, 5 Counties Salmonid Restoration Group, and the USFS Legacy Roads program, watershed restoration efforts are in various stages of planning and implementation.
  • The decision for the Orleans Transportation and Road Restoration Environmental Assessment (EA) (2007) is in the final stages of implementation of road decommissioning and storm proofing.
  • Partnerships with the 5 Counties program, NMFS, California Department of Fish and Wildlife, National Federation of Watershed and Fisheries resulted in further efforts to remove fish passage barriers for anadromous salmonids in Griffin Creek on the Smith River and Sharber-Peckham Creek on the Trinity River.
  • West Ishi Transportation Analysis Process (TAP) was recently completed on the west side of the Ukonom District, Klamath River.
  • The Smith River National Recreation Area Restoration and Travel Management Environmental Impact Statement, Forest-wide Aquatic Restoration EA, and Forest Stormproofing Project EA are ongoing.
  • Future watershed and fisheries restoration efforts are also currently in various stages of planning and those projects can be found on the Six Rivers Schedule of Proposed Action list.

For more information on the Six Rivers Watershed and Fisheries Restoration Programs, contact Carolyn Cook or 707-441-3551.

For a broader look at ecological restoration program, refer to the Six Rivers Ecological Restoration overview.