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Wolfe Creek Instream and Riparian Enhancement Project

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The TEP has initiated a project to enhance instream and riparian habitats along Wolfe Creek, a tributary of the Nestucca River. The project will:

1) Restore fish passage by replacing a culvert,
2) Enhance salmon spawning and rearing habitat through additions of large wood, and
3) Restore riparian habitats degraded from years of grazing.

Wolfe Creek

Draining 2.9 mi², Wolfe Creek enters the mainstem Nestucca River at approximately rivermile 13, 2.5 miles east of Beaver, Oregon. Swab Creek, a small tributary, drains into Wolfe Creek from the east at rivermile 0.50. Wolfe Creek flows from US Forest Service land, meanders through low gradient private agricultural land, and empties into the Nestucca River.

Over three miles of salmon spawning and rearing habitat exists in the Wolfe Creek watershed, 2.3 on the mainstem and 0.9 miles on Swab Creek. Coho, winter steelhead, fall chinook, and coastal cutthroat all inhabit Wolfe Creek.

Limiting Factors

culvert outlet

Fish Passage
Wolfe Creek Road crosses Wolfe Creek by way of a 60-foot long, 9-foot wide by 11-foot tall elliptical corrugated metal pipe culvert. This undersized culvert is sloped at 2% is not embedded in the stream channel, and the outfall is slightly perched. The narrow shape of the culvert and the perched outfall hinder the ability of the culvert to hold streambed material. The high water velocities in the culvert and an 18 inch jump over bedrock at the inlet result in a difficult passage situation for migrating fish entering Wolfe Creek. Under most conditions water depth in the culvert is less than a foot deep and the water velocity is at the upper limit of that passable by adult and juvenile salmon.

18" drop

The Nestucca/Neskowin Watersheds Culvert Prioritization and Action Plan for Fish Passage identifies the Wolfe Creek culvert as a high priority for replacement. Located only 50 feet from the mouth of the Nestucca River, this culvert is the only one in the Wolfe Creek watershed.

Lack of channel complexity and wood
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Instream Habitat
The USFS surveyed Wolfe Creek and Swab Creek in 1980 and Wolfe Creek in 1997, collectively painting a picture of the past and present conditions. The 1980 survey described an abundance of large log jams (natural and accumulations from upslope logging in the headwaters) on both Wolfe and Swab Creek that were recommended for removal or modification to enhance fish production. These large accumulations were removed and the 1997 survey reports low amounts of instream wood. Wolfe Creek's lower reach retained much of its historic meander, channel braiding, and abundance of spawning gravels despite the loss of instream structure.

Degraded riparian area
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Riparian Habitat
The lower 0.7 miles of Wolfe Creek (Reach 1) meanders through private agricultural land (hobby farm and commercial dairy) that is heavily impacted from past and current grazing practices. A 300 ft section near the mouth on the west side of the stream is impacted by a hobby farm with horses, and soon livestock. The rest of the lower reach above the culvert (both sides) is impacted by the commercial dairy. Some fencing on the west side excludes livestock in most places, but offers no riparian buffer. A wide buffer that is not currently grazed, up to 100 ft in a few locations, exists in the lower reach between Reddaway Road and the stream. This allows for the relatively intact riparian area that is dominated by blackberry and scattered alders and poplar.

Logging in the upper reaches of Wolfe Creek and Swab Creek between the 1950's and 1990's significantly contributed to the loss of intact riparian areas. Some of the private land has never been logged and offers a healthy riparian area.

Project Goals

An engineering solution is required to replace the existing culvert with a crossing structure that will allow for the adequate passage of flood waters and sediment, and provide long-term fish passage for adult and juvenile salmon. In addition, a solution is desired that will provide for a real or simulated stream bottom underneath Wolfe Creek Road.

The goals of this project are to:

restore adult and juvenile fish passage to critical spawning and rearing habitat
enhance freshwater fish habitat
improve hydrologic and sediment routing processes
improve water quality in the lower reach of private agricultural land
educate the local community on watershed processes and restoration benefits

The Project

Culvert Replacement
This project proposes to replace the existing 9-foot wide, 11-foot tall, 60-foot long elliptical culvert with a 22-foot wide, 11-foot tall, 68-foot long bottomless arch culvert that will span the entire 22-foot active channel width. All in-water work will occur during ODFW's in-water work period (July 1 - September 15, 2007). A water diversion will isolate the work area and a detour road will provide continuous access to private residences on the west side of Wolfe Creek.

The proposed culvert replacement design approach follows the ODFW Stream Simulation Method for Fish Passage Criteria at culverts and bridges (ODFW, 2004). The main criteria of this method is that any bridge or culvert stream crossing shall not alter the character of the stream significantly from that found just up and downstream of the crossing. The proposed culvert width (22 feet) is sized to meet the upper end of the existing active channel width range (18-22 feet) found in the lowest reach of Wolfe Creek. The project design includes constructing a 'roughened channel' streambed beneath the open bottom arch culvert.

Carcasses from spawned-out salmon in Wolfe Creek

Instream Enhancements
Large wood placed in Wolfe Creek and Swab Creek will trap spawning gravels, scour deep rearing pools, and provide cover. The addition of logs to the stream channel, combined with existing large wood in the channel, will approach ODFW benchmarks. This density is agreeable to the landowners and will enhance salmon spawning and rearing habitat. All instream work will occur during ODFW's in-water work period (July 1 - September 15, 2007).

Excavator Log Placement
Excavator log placement will occur in the lower reaches of Wolfe Creek and Swab Creek where the stream is accessible. The USFS is providing 137 conifer logs, 18 of which will have a rootwad. Logs will be hauled from upland areas of another watershed and staged at the project site. An excavator will place logs at natural pinch points where wood would normally collect and wedge between riparian trees for stability. Where riparian trees are not present, boles will be buried into the banks for stability with rootwads protruding into the stream. Wood used will be sized to ODFW guidelines. There will be no cabling or pinning to restrict wood movement.

On the Wolfe Creek mainstem, the excavator placement ends where stream access further upstream may compromise the integrity of the stable riparian area bearing large conifers. There are also no roads near the stream.

Helicopter Placement
Helicopter log placement will occur upstream of the excavator placement. The USFS is providing 52 conifer logs, 19 of which will have rootwads.

The Wolfe Creek helicopter placement is tied to an existing 2007 helicopter placement project planned by the BLM on Bear Creek in the upper Nestucca. Combining the two projects reduces the helicopter move-in costs for each project. After the BLM project is completed, Columbia Helicopters Inc. will place wood in Wolfe Creek (likely the same day).

Riparian Enhancements
Fencing and off-channel watering will be constructed along the lower half-mile of Wolfe Creek, beginning at the mouth (total of one mile with both banks). Fencing setbacks will meet the standard 2 x bank height + 10 feet. Approximately 810 native shrubs and trees, including spruce, cedar, hemlock, maple, and cottonwood, will be planted within the newly fenced riparian areas. In the upper forested reach where the helicopter large wood placement will occur, conifers will be planted in openings and beneath alders.

In Winter 2006/2007 the SWCD constructed fencing between the lower half-mile and the helicopter reach. The NNWC planted the newly fenced riparian setback with native trees and shrubs.

Schedule