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Large wood installation projects
Video: annual large wood meeting
On November 7th, 2024, King County's Water and Land Resources Division hosted a virtual presentation on the importance of Large Wood features in our habitat restoration projects. They also showcased a number of upcoming and continuing projects and their planning phases. that are based throughout King County. Project Manager contacts and resources are also presented in the video.
King County’s rules for public safety when adding large wood to rivers say that the Department of Natural Resources and Parks must create and keep a list of projects where large wood will be, or might be, placed in a river or stream. This list is updated often, and two public meetings are held each year to share information and talk about the projects. You can sign up to get updates about the projects and the public meetings below.
Upcoming and active projects
Desimone Levee Major Repair USACE
Location: The Desimone Levee Major Repair USACE project is in the City of Tukwila along the right bank of the Green River from River Mile 14.6 to 15.2. Manufacturing and warehouse buildings are located adjacent to the levee and the Green River Regional Trail runs along the top of the levee through the project area.
Purpose and importance: The Desimone Levee is part of a larger levee system along the right bank of the Green River which provides flood risk reduction benefits to highly developed areas in the cities of Renton, Tukwila, and Kent in King County, Washington. The levee incurred significant damage during flood events in February 2020, creating a flood and safety risk. Because of the high level of risk, there is urgency in repairing the flood facility.
Goals and objectives: The project is being implemented by the U.S. Army Corps of Engineers (USACE) under the P.L. 84-99 Levee Rehabilitation and Inspection Program (PL 84-99) and includes a Locally Preferred Plan (LPP). The project will repair levee slope failures, shift the levee alignment and trail landward to the extent possible for a more stable embankment, provide buried scour protection where needed, address seepage concerns through construction of a floodwall, and integrate habitat improvements. Habitat improvements will include placement of log sets, boulder features, and single logs, as well as extensive revegetation with native riparian plants.
Existing site conditions:The Lower Green River is physically isolated from its floodplain by a near continuous system of levees and revetments and is hydrologically isolated from the floodplain due to riverbed incision and altered flows from operation of the Howard Hansen Dam. Shoreline and riparian areas lack mature trees. Through the project reach the river channel is confined on both sides by levees and the shoreline and riparian areas lack mature trees. There is almost no naturally occurring large wood in the project reach; any wood that may be present at a given time quickly moves through the reach, since there is no structural complexity to functionally retain it. The project is in a section of the Lower Green River surrounded by dense development, which greatly limits opportunities for large-scale habitat restoration.
Recreational uses, timing, intensity: Low to moderate use for floating, boating, and fishing.
Intended large wood function: The primary purpose of the large wood placement is to provide areas of slower moving water for small out-migrating salmonids to seek refuge to feed and rest in a range of flow conditions.
Project status: The Corps of Engineers has issued a Draft Environmental Assessment (EA) (PDF) and 65% Plans Sept. 12, 2024 with a 30-day comment and review period. Opportunity for comments and feedback on this project was through the U.S. Army Corps of Engineers National Environmental Policy Act (NEPA) public consultation process and Draft EA. Please see the Draft EA for further information including Corps of Engineers contact information and project plans.
Anticipated construction: Spring 2025 through November 2026
Belmondo Levee 2020 Repair
Location: The Belmondo Levee is located approximately at River Mile 10.4 of the Cedar River, four miles southeast of Renton and four miles north of Maple Valley in unincorporated King County. It is just east of SR 169 (Renton-Maple Valley Road) and on the east side of the Cedar River Trail.
Purpose and importance: The Belmondo Levee protects critical infrastructure including the Maple Valley Highway (SR 169), Cedar River Trail, and a buried regional fiber optic trunk line. If unaddressed the damage will likely expand resulting in potential impacts to critical infrastructure and loss of public property.
Goals and objectives: The goal is to reduce flood risks and successfully inform area property owners, residents, tribes, permitting agencies, and other interested parties about the project. To garner tribal and stakeholder support through engagement in outreach, and ongoing communications about the project. Ensure effective communication to recreationalists about Cedar River Trail closures and construction impacts to land and river use to recreationalists.
Objectives towards achieving those goals include:
- Deliver clear, concise, and consistent messages about the project and its elements to build project understanding and support.
- Provide accurate and timely information, in multiple formats, to reach target audiences.
- Incorporate Department of Natural Resources and Parks (DNRP) Equity and Social Justice Policy around community engagement in outreach strategies.
- Engage in dialogue with the Muckleshoot Indian Tribe and stakeholders by providing a variety of opportunities for information sharing and feedback.
- Respond to concerns, questions, and suggestions in a timely manner.
Existing site conditions: The Belmondo Levee is approximately 600 feet long and located at approximately River Mile 10.4 the Cedar River. The levee protects the adjacent Cedar River Trail, SR 169, and a buried fiber optic line.
After flooding in January 2009, an emergency repair was implemented, with additional maintenance work in 2012 to rebuild 100 feet of the northern end of the levee. In 2013, an enhancement project reconstructed 370 feet of the facility, incorporated instream structures and enhanced the quantity and quality of aquatic habitat by establishing deep pools for fish, as well as shade and cover.
Flooding in February 2020 on the Cedar River damaged the upstream end of Belmondo Levee. Erosion and loss of toe and face rock resulted in an over-steepened and unprotected levee core. The damage is approximately 100 feet long and includes damage to the engineered log jam that is part of the flood protection facility. Upstream extension of the flood protection facility will be considered in anticipation of continued meander development and embankment erosion.
The Cedar River is popular with recreationalists, both in-water and on the Cedar River Trail, which will be considered in outreach throughout the project life, design, and implementation.
Recreational uses, timing, intensity: A partial closure and/or detour of the Cedar River Trail will need to be closely coordinated with King County Parks and communicated effectively to users of the trail.
Impacts to commuters on State Route 169 are currently unknown, but it is a heavily trafficked roadway and will likely require traffic control for trucks and equipment entrance and egress. Traffic control will be communicated through stakeholder outreach in advance of the project. The 2013 project had minimal impacts to SR169.
Intended large wood function: The intended function of the large wood at the project site is to shift high flow pace of the river away from the levee and toward the center of the river channel. The increased shading and cover will provide refuge for wildlife and serve as fish habitat. The flow patterns created by the deflectors should create conditions that encourage wood to pass through the main channel.
Project status:
- Instream project design checklist (1.58 MB)
- Belmondo Repair Determination of Non-Significance (342 KB)
- BelmondoSEPAChecklist_English (923 KB)
- Belmondo SEPA Checklist_Espanol (923 KB)
Anticipated construction: 2025
Momb Revetment 2020 Repair
Location: The Momb revetment is located near River Mile 10.4 of Issaquah Creek, near the intersection of Southeast 156th Street and Southeast Cedar Grove Road.
Purpose and importance: The Momb Revetment on Issaquah Creek helps reduce the risk of flood and erosion damage to Southeast 156th Street. The street provides sole access to approximately 30 homes. There is urgency to repair this damage due to probability of continued erosion that will likely exacerbate the damage and threaten Southeast 156th Street.
Goals and objectives: Construction will repair approximately 100 feet of damage to the revetment. The repair will reduce flood risk to people and property and will also benefit fish habitat in Issaquah Creek.
Existing site conditions: Flooding in February 2020 damaged the revetment creating a flood and safety risk to Southeast 156th Street, Cedar Grove Road Southeast, and public utilities. The damage includes loss of rock, exposed riverbank material, and two cottonwood trees at risk of falling into the creek.
Recreational uses, timing, intensity: Issaquah Creek has a low level of recreational use.
Intended large wood function: Wood will be placed for habitat enhancement along the channel and in the floodplain.
Project status: 60% design is anticipated during fourth quarter 2023.
Anticipated construction: 2025
Stossel Revetment Major Repair
Location: The Stossel Bridge Major Repair project is located approximately 2 miles north of the City of Carnation, in unincorporated King County, on the Snoqualmie River at river mile 21.9.
Purpose and importance: The purpose of this project is to address significant ongoing erosion, establish long-term protection provided by the Stossel Bridge Right Bank Revetment, and protect a sole access King County road.
Goals and objectives:
- Protect public and private infrastructure.
- Enhance aquatic and riparian habitat.
- Minimize long-term maintenance needs and life-cycle costs.
Existing site conditions: The Stossel Bridge Right Bank Revetment protects a county road, utilities, agricultural and private property from erosion along the Snoqualmie River. The revetment has been repeatedly damaged over the years by ongoing erosion and was repaired in 2017 and 2018. Additional damage was found in summer 2020 that must be repaired to prevent bigger and more costly repairs from being needed. There is an urgency to repair the revetment due to the probability that erosion will continue, presenting risks to the adjacent road and threatening sole access to two private properties.
Recreational uses, timing, intensity: A 2013 River Recreation Study showed low recreational use within the project reach, with the majority of users being adults. Other observations included some jet ski use and personal fishing boat use.
Intended large wood function:
- Reconstruct and reinforce the right bank revetment while enhancing local habitat.
- Incorporate settling log structures to improve habitat and address toe erosion.
- Enhance toe protection and habitat complexity along the 2017 and 2018 repairs.
Project status: Final Design is complete.
Anticipated construction: 2025
NE Auburn Creek
Location: The NE Auburn Creek Restoration Project is located at river mile 25.3 in unincorporated King County between the City of Kent to the north and the City of Auburn to the south.
Purpose and importance: Restoration of the mouth and lower reach of NE Auburn Creek and adjacent wetland presents a rare opportunity in the Lower Green River sub-watershed to reconnect floodplain habitat to the mainstem channel, where there is a critical need for off-channel rearing and refuge habitat for juvenile salmonids, while providing more reliable flood protection to the adjacent property owners.
Goals and objectives: The overall goal of the NE Auburn Creek Restoration Project is to rehabilitate degraded floodplain in the Lower Green River and restore access to critical rearing and refuge habitat for juvenile salmonids. The project objectives include:
- Replace old flap gate with fish-friendly flood gate that will remain fish-passable whenever the gates are open while maintaining existing levels of flood protection for landward properties.
- Restore access to the 20,000 linear foot drainage network of NE Auburn Creek to serve as off-channel rearing & refuge habitat.
- Improve conditions and access to 2.7 acres of riparian wetland.
- Maintain and improve riparian buffer along 2,000 feet of the Lower Green River.
- Preserve access to Horsehead Natural Area and Horesehead Farm.
- Improve drainage where possible for Horseneck Farm.
- Maintain existing flood protection for adjacent lands.
Existing site conditions: The river in this reach flows through a deeply incised channel that has been simplified by the extensive flood control features along its banks. There is very little structure to the channel from woody debris or boulders. This reach of the river is very low gradient and flows through a broad floodplain created by both the Green River and, prior to its diversion, the White River, which drains Mt Rainier and therefore carries a much higher sediment load than does the Green. Sediment deposited in this floodplain by the White River to the south has pushed the Green River to the north and forced it to cut a deep channel through the sediment which is partially responsible for the incised geometry of the channel. Extensive flood control facilities, including the Nursing Home Levee on the opposite bank of the River from the project area, have further contributed to the simplification and incision of the channel. These factors also disconnect the floodplain from the river. At low flow, the wetted river channel is approximately 25 feet below the adjacent floodplain and the banks between are very steep, approaching vertical in places. Access to the river channel is therefore difficult from the floodplain above, though there are several places along the opposite right bank where access is possible from a paved trail that runs along the top of the Nursing Home Levee.
Recreational uses, timing, intensity: In 2013 during King County’s Synthesis of River Recreation Studies, in-water use of this reach of the river was low (.05 people per day). Compared to the other two reaches of the Green River studied (upstream at Whitney Bridge at RM 41.3, and Auburn-Black Diamond to Isaac Evans Park from RM 29.1-33.4), the Lower Green River through the project site had much lower numbers of people per day, the highest life vest usage, and the highest use of boats with paddles rather than rafts and inner tubes.
Intended large wood function: Wood placed in the newly constructed channel of NE Auburn Creek will serve primarily to enhance habitat for both fish and wildlife but will also stabilize potentially vulnerable channel banks and provide roughness and stability to the bed of the new channel.
Project status:
- Instream design checklist (588 Kb)
- 30% Design (14 Mb)
- Final Design anticipated February 2026
Anticipated construction: Summer of 2026, pending construction funding.
Tabor-Crowall-Brodell Revetments 2020 Repair
Location: Right bank of the Cedar River at River Mile (RM) 2.7 (Tabor-Crowall) and 3.4 (Brodell).
Purpose and importance: Repairing these revetments reduces flood risks to people and property. Timely action may also minimize damage to fish habitat and prevent the need for costly emergency repairs in the future.
Goals and objectives:
- Reduce flood risk to people, property, and infrastructure.
- Ensure new flood protection infrastructure meets current engineering standards to minimize maintenance costs and seismic risk.
- Improve natural river processes, function, and habitat, where feasible.
- Meet FEMA requirements to design and implement repairs to the Tabor-Crowall revetment.
These goals align with the stated goals of the DNRP to protect and restore aquatic habitat and to reduce risk to public safety.
Existing site conditions: Predevelopment geomorphic conditions at the project sites likely resulted in relatively low channel migration rates and potentially even sediment-starved, incised conditions. This condition relates to deglaciation and the relative patterns of deposition and incision as the major rivers in the Puget Lowland begin to develop an equilibrium profile in a formerly glaciated landscape. Since European settlement in the basin, three major changes have further accentuated the natural incision and lack of channel migration at the project sites. The first of these major changes was at the Cedar River’s outlet near Renton. Before 1912, the Cedar River drained into the Black River, not Lake Washington. A series of actions caused the Cedar River tailwater to become
controlled by the locks in Ballard, which were considerably lower thus increasing the local gradient of the river. Second, the hydrology and geomorphology of the Cedar River changed due to operations at Seattle Public Utilities facilities in the upper basin (i.e., Masonry Dam, Chester Morse Lake, and the Landsburg Diversion). These facilities have changed the high- and low-flow characteristics of the river and reduced sediment supply to the project sites. Third, development and land-use conversion affect hydrology and sediment supply similar toother urbanized environments (i.e., peakier hydrology and increased sediment input).
Recreational uses, timing, intensity: Recreational use of the river in the project sites is intense compared with equivalent river stretches in King County, although most boaters exit upstream of the project sites; The Cedar River Recreation Study: Floating the Cedar River (King County 2011). The recreation study also documented that most vessels observed on the river were floating tubes. Because this study was conducted during the summer when usage is higher due to warm weather, it does not address whether there are differences in use during the spring, fall, and winter seasons.
Intended large wood function: The large wood installation at the Tabor-Crowall and Brodell revetment repairs will create channel complexity and will allow natural movement and settling of the wood over time. Added deflector jams in places will provide safety for Cedar River recreational users.
Project status: 30% Design
Anticipated construction: Summer 2026
Fort Dent Levee 2020 Repair
Location: The Fort Dent Levee is located in the City of Tukwila along Interurban Ave S, it is on the right bank of the Green River adjacent to Fort Dent Park between river mile 11.02 and 11.84.
Purpose and importance: The Fort Dent Levee protects the Green River Trail, Fort Dent Park, and Starfire Sports Complex from flooding. Additionally, the project goals align with the stated goals of DNRP of protecting and restoring habitats, ecological functions and aquatic conditions, as well as fostering community-building and healthy living. The project goals also align with the reach goals listed within the 2019 Tukwila Shoreline Master Program and the 2021 WRIA 9 Salmon Habitat Plan.
Goals and objectives:
- Reduce flood risk to people, property and infrastructure.
- Enhance aquatic and riparian habitat.
- Minimize long-term maintenance needs and life-cycle costs.
- Construct project in the summer of 2026.
Existing site conditions: The Fort Dent Levee is over-steepened and has experienced damage at multiple locations in recent years. The lower Green River has been heavily influenced by two notable historical events: the permanent diversion of the White River into the Puyallup basin in 1906, and the construction of Howard Hanson dam in 1961.
The project reach is channelized, with hardened banks, levees, and infrastructure on either side of the river. The 100-year flood is contained within much of the channel and there was no naturally-deposited large wood observed at the time of the site visit. The riparian zone consists of steeply sloped banks and a narrow corridor at the top of bank adjacent to the trail. Himalayan blackberry is the dominant species vegetating the bank; shade, litterfall and insect fall from the bank is limited. There are a few scattered trees riverward of the trail, including willow species, birch and poplar.
The Green River in the project site is used as a transition zone for smolts to adjust to saltwater environments. With a bed composition of sand and other fines, this is not a spawning reach. The following species with various designations under county, state, or federal programs were noted to occur in the Green River in the project vicinity: Coho salmon, Cutthroat trout, Steelhead trout, Chum salmon, Chinook salmon, Pink salmon, Sockeye salmon, and bull trout.
Recreational uses, timing, intensity: The project site is adjacent to the Green River Trail and Starfire Sports Complex, both of which remain active and heavily utilized throughout the year. The main channel is used for recreational floating in the summertime, but there is no river or boating access at the project area.
Intended large wood function: The primary purpose of the large woody material structures are to increase hydraulic complexity and provide habitat diversity for fish that is available over a range of flows, as well as to provide additional bank roughness. The logs structures are oriented with the rootwad facing upstream and are shingled so that the root bole is tucked behind the next upstream log. This orientation minimizes risk to recreational boaters while still providing bank roughness, stability, and habitat benefits. The elevation of the toe logs will be approximately 9-11 feet, ensuring frequent inundation even during low flows.
Project status:
Anticipated construction: Summer 2026
North Fork Confluence Revetment Removal
Location: North Fork Snoqualmie River in Three Forks County Park.
Purpose and importance: The Scott Revetment was built around the year 1960. The purpose of the Scott Revetment was to reduce erosion of a privately-owned property used for livestock grazing, Today, the project area is entirely within a natural area owned by King County Parks. The revetment is not needed because it no longer protects farmland, roads, or infrastructure, yet public funds are still being spent to inspect and maintain it. Removing the Scott Revetment, which is approximately 570 feet long, will restore natural, habitat-forming processes, reconnect the river to the floodplain, and be cost-effective with flood risk reduction public funds. Removal of the Scott Revetment is also consistent with recommendations in the Upper Snoqualmie Resilient River Corridor Management Plan published by the Snoqualmie Tribe in 2022.
Goals and objectives:
- Restore natural river processes by reconnecting the North Fork Snoqualmie River to its floodplain
- Improve habitat conditions for fish and wildlife
- Reduce cost of maintaining a revetment that provides no public benefit
- Collaborate with Snoqualmie Tribe to implement the project consistent with Upper Snoqualmie Resilient River Corridor Management Plan
- Install educational signs in Three Forks County Park
Existing site conditions: The North Fork Snoqualmie River is geomorphically dynamic and subject to ongoing channel migration. An examination of historic aerial photos and LiDAR imagery provide strong evidence that this area of the upper Snoqualmie River valley has a long history of ongoing river channel changes, especially upstream of the 428th Avenue SE Bridge. Naturally occurring large wood is present in the river and actively recruited to riverbanks and other riverine features.
Recreational uses, timing, intensity: Recreational use of the River in the project stretch is fairly light and predominantly casual users in the warmer months of the year. This includes fishing, wading and casual tubing and floating. American Whitewater does not recommend rafting or kayaking in the project reach given rapidly changing river and wood conditions. Upstream from the project reach, the river is considered an expert-level white water system. On the landward side of the revetment an older grove of trees nearby is used for tree climbing classes. There is no or little hiking in this area, although dog walkers are observed near the river in the project area.
Intended large wood function: The project is not installing large wood, but will place approximately 30 unanchored trees near the edge of the river after their removal during construction. This wood is expected to become mobilized during high flows. Mature cottonwood trees that are growing near the top of the bank will be retained as possible during project construction. However, natural recruitment of these trees following project implementation is expected to occur over time as the project site evolves. Re-establishing this natural large wood process at the project site is consistent with the approach at the nearby Shake Mill area and open space management at Three Forks Park.
Project status: The King County Flood Control District is considering project alternatives at this time. 30% plans and the large wood checklist are expected to be available in Spring 2025.
Anticipated construction: Summer to fall 2025
Dutchman Road Revetment Repair
Location: The Dutchman Road Revetment is located on the north bank of the Snoqualmie River, about one mile downstream of the Northeast Woodinville Duvall Road Bridge.
Purpose and importance: In recent years, high river flows have damaged parts of the revetment causing a safety risk. The riverbank could erode further and damage West Snoqualmie River Road Northeast. This repair project will reduce flood and riverbank erosion risks to property, local utilities, and roads.
Goals and objectives:
- Repair damage and improve stability of the revetment to reduce flood risks.
- Conduct repair in a timely manner to prevent more expensive emergency repairs and long-term maintenance needs.
- Maintain or improve habitat for salmon and other fish.
Existing site conditions: Information will be provided soon.
Recreational uses, timing, intensity:
- River-wide use of small boats, rafts, and jet skis limited to summer recreational activity.
- Taylor Landing boat launch approximately 1 mile upstream of the project area.
Intended large wood function: Information will be provided soon.
Project status: 30% Design is complete.
Anticipated construction: Summer 2026
Lower Frew Levee Setback
Location: The Lower Frew Levee Setback project is in the City of Carnation on the northern bank of the Tolt River, between SR 203 and the Snoqualmie Valley Trail.
Purpose and importance: Replace the existing Lower Frew Levee with a new levee built farther away from the river and replace a frequently flooded culvert under State Route (SR) 203 with a new raised bridge. This will help reduce flood risks, improve vehicle access on SR 203 during floods, and improve habitat along the lower Tolt River.
Goals and objectives:
- Reduce risk to people, property, and infrastructure due to flooding and channel migration hazards.
- Restore river processes and functions.
- Provide safe trail access and public use of the site
Existing site conditions: Information will be provided soon.
Recreational uses, timing, intensity:
- Low recreational use within the project reach relative to Snoqualmie River mainstem and the confluence of the Snoqualmie and Tolt rivers with most users being families and swimmers (2013 River Recreation Study).
- Other observations: walking (on trails and gravel bars) and cycling (on trails)
Intended large wood function:
- Deflect flow away from the setback levee and protect the new bridge piers with wood structures.
- Enhance habitat complexity with wood structures.
Project status: King County is working toward 30% Design in spring 2025.
Anticipated construction: First phase of construction planned for summer 2027.
Rutledge Johnson
Location: The Rutledge Johnson levee is located on public property on the south bank of the Cedar River in the Mouth of Taylor Creek reach between River Mile 13.1 and 13.5. The site is about 1.1 miles northwest of the State Route 18-Highway 169 interchange near Maple Valley. The site is accessible by foot at the address: 19934 218th Pl SE Maple Valley, WA, 98038.
Purpose and importance: This project emphasizes floodplain reconnection and improved access to critical off-channel habitat through removal of an obsolete section of the Rutledge Johnson levee, and is prioritized in the WRIA 8 Chinook Salmon Conservation Plan. The loss of critical habitat features due to bank armoring and disconnection of the river channel from side-channels and floodplains has been identified as a primary factor limiting Chinook salmon productivity in the Cedar River.
Goals and objectives: In reconnecting the floodplain, the project outcomes will be to improve salmon habitat, specifically:
- improve the quality, quantity and sustainability of in-stream and off-channel habitat for Chinook, steelhead and other Puget Sound salmonids that rely on the Cedar River for spawning and rearing through restoration;
- maintain or reduce current levels of flood and erosion risk to people, property and infrastructure; and
- allow public access to the site for safe, passive recreation considering the changing nature of the river and its banks.
Existing site conditions: Previous homes on the site were demolished after King County acquired the parcels for flood protection purposes. These areas have been replanted, and the 16-acre site is a mosaic of upland and wetland floodplain habitat with a mix of forested, shrubby, and grassy areas.
Recreational uses, timing, intensity: Innertubers use this reach of the Cedar River in summer months in fewer numbers than downstream areas like Renton. The site is open to passive recreation at all times of year and limited parking is available at the entrance to the site off of 218th Pl SE.
Intended large wood function: Improve habitat and geomorphic function.
Project status:
- Information will be added soon.
Anticipated construction: Summer 2025.
Auburn Narrows Floodplain Reconnection Project
Location: The Project is located within the Auburn Narrows Natural Area on the left bank of the Green River downstream (west) of Highway 18.
Purpose and importance: The lack of off-river salmon rearing habitat in the Green/Duwamish watershed negatively impacts native fish species, especially Chinook salmon and steelhead (both listed under the Endangered Species Act). The lack of this habitat type is the greatest limiting factor for the recovery for these two species in the watershed. Greater riverine/floodplain connectivity and improved floodplain flow patterns mean that fish can access important habitat features like adjacent wetlands and side channels for more time of the year and through a variety of channels. Inducing channel aggradation will also result in a rise in baseflow water elevations, which will encourage the river to flow throughout the floodplain more frequently, providing even more access to habitat over time.
Goals and objectives:
- Remove remaining impediments to channel migration and habitat-forming processes from the channel and floodplain to increase off-channel and channel margin fish habitat (for rearing and refuge), which may include removing the buried revetment beneath the access road (initially placed to protect Tacoma Public Utility’s mitigation project) and removing the levee’s toe rock.
- Install instream structure and hydraulic roughness (i.e., large wood and gravel bars) to induce channel aggradation within the reach and increase floodplain connectivity. New roughness elements would be patterned after natural features intended to deform over time. Large wood structures will be designed and installed to resist drag and buoyant forces for the predicted 100-year flow, but stability will change over time as the channel adjusts in response to flow. Structures are intended to initiate a sustainable change in channel form but will not persist in their as-built configuration.
- Revegetate areas lacking sufficient native vegetation and place large wood, snags, and/or slash piles throughout the site.
- Remove remaining infrastructure in floodplain, including groundwater well.
Existing site conditions: The middle Green River sub-watershed provides spawning and rearing habitat for eight species of salmonids, including Chinook, steelhead, coastal cutthroat trout, coho, pink, and sockeye. Salmonid habitats associated with the project site include both mainstem and side channel habitats. Little instream large woody material is found in this straightened section of the river, but a large logjam is present downstream at approximately RM 32.5.
At the project site, the river shows evidence of impacts from flow control, levee construction, railroad and road bridge construction as well as more recent efforts toward restoration. The first major action to impact geomorphology at the site was the construction of the Burlington Northern Rail Line and the construction of bridge crossings for Auburn-Lake Holm Road. These crossings have constrained the floodplain to roughly one third of its historic width and held the channel along the north valley wall for over 100 years. This constriction was lengthened when the Highway 18 bridge was constructed and it has contributed to a simple, straight, channel for approximately 1500 feet upstream and downstream of the bridge crossings.
Recreational uses, timing, intensity: The Auburn Narrows Natural Area is mostly used for informal recreation. The riverbanks are popular with anglers during the fall. The river itself is closed to boating in this reach due to the presence of a large log jam downstream at RM 32.5. The Auburn Narrows Natural Area also has encampments, which are being taken into consideration in site use, design, and constructability discussions. The right bank of the Green River in this reach is owned by Green River Community College and the Washington Department of Natural Resources. There is an access trail from the college to an existing side channel on the right bank, which is presumed to be used for recreation.
Intended large wood function: Large wood at the site consists of mid-channel key logs, inlet jams, bank jams, standing snags, and habitat wood piles.
The mid-channel key logs are intended to act as the primary nucleation points for the Project’s wood lattice. The mid-channel key logs will be distributed throughout the Project reach of the Green River and will be primarily salvaged from on site.
The purpose of the inlet jams is to provide cover near the confluence of the inlet and the mainstem Green River as well as to direct flows into the thalweg of the inlets.
The purpose of the bank jams is to provide additional cover and complexity within the mainstem Green River as well as connect to the mid-channel key logs to provide additional nucleation points and increased complexity in the wood lattice.
Standing snags will be placed throughout the graded areas to provide valuable wildlife habitat and to naturally recruit floodplain wood. Snags will be embedded vertically in the soil to emulate dead trees and provide valuable nesting and foraging habitat. Habitat wood piles and downed wood will also be placed throughout the floodplain and graded areas to provide additional wildlife habitat and hydraulic roughness.
Project status: In final design,
Anticipated construction: Summer 2026