Fender Mill Alcove

Yakama Nation Fisheries Upper Columbia Habitat Restoration Project contracted Inter-Fluve to perform a reach assessment, and design of a 2,200-foot-long groundwater-fed side channel to provide year-round rearing habitat for summer chinook and steelhead. The side channel intercepts groundwater, collecting hyporheic water near the river, and conveys it to the head of the side channel. The developed spring provides approximately 4 cubic feet per second of flow in the new side channel during the lowest Methow River flows.

Why groundwater? Groundwater buffers the water temperature, helping to maintain a more consistent and optimal fish rearing temperature. During the peaks of winter and summer, groundwater-fed side channels provide critical thermal refuge habitat for juvenile fish which experience physiological stress with overly warm or cool temperatures.

Aerial view of the 2,200-foot-long groundwater fed side channel being constructed. Photo: Yakama Nation

A 500-foot-long ground water infiltration gallery collects groundwater (yellow dots) and conveys it to the side channel to provide year-round rearing habitat for summer Chinook and Steelhead.

Aerial view of the channel being constructed. Photo: Yakama Nation

Hundreds of imported and salvaged large wood pieces were used to create complex cover habitat in created pools.

Clackamas River Basin

In 1877, Livingston Stone, employed by the U.S. Fish Commission to explore potential hatchery sites throughout the Columbia River Basin, professed that “probably no tributary of the Columbia has abounded so profusely with salmon in past years as this river (the Clackamas).” Unfortunately, over the next 150 years, salmon populations in the Clackamas plummeted as a result of overfishing, dams, logging, mining and habitat destruction.

Since 1996, Inter-Fluve has completed 22 projects on the mainstem Clackamas River and its tributaries aimed at recovering lost salmonid habitat. Projects have included a flood damage assessment following the 1996 100-year-flood, the $4 million dollar River Island Channel & Floodplain Restoration project, the design and construction of a 700-foot-long side channel and a groundwater-fed backwater channel at Milo McIver State Park, and development and implementation of a side channel monitoring plan. Below are examples of some of the work we’ve done throughout the Clackamas watershed.

Salmonids find cover under one of hundreds of pieces of Large Woody Material that were placed in a side channel at Milo McIver State Park on the Clackamas River.

In 1889, after a day of steelhead fishing on the Clackamas River, Rudyard Kipling proclaimed: “I have lived! The American continent may now sink under the sea, for I have taken the best of it, and the best was neither dollars, love, nor real estate.”  Photo: Fishing at the mouth of the Clackamas River circa 1937. Credit: Courtesy of Old Oregon Photos (Original from Clackamas County Historical Society)

We developed design plans and oversaw construction for the River Island Channel & Floodplain Restoration project. It involved rebuilding riparian-forested floodplain (right side of photo), reclaiming alcove habitat, and reconnecting Goose Creek (left side of photo) to the Clackamas River mainstem.

Pre-project photo of a historical side channel at Milo McIver State Park. In 2015, in this location, a 200-foot-long perforated pipe underground collects hyporheic flow (water moving through gravel bars) and delivers it into a 700-foot-long backwater channel.

Post-construction photo. Excavated along a historical channel alignment, hyporheic flow now mixes with groundwater, and provides salmonids cool water in the summer and warm water in the winter.

In 2004, Inter-Fluve worked with the Oregon Wildlife Heritage Foundation (OWHF) and Portland General Electric (PGE) to design and construct 4,400 feet of perennial side-channel habitat known as the Parson’s project.

One year post-construction, vegetation begins to re-establish along the Clackamas Parson’s project.

Juvenile salmonid observed utilizing large wood placed as part of the Milo McIver project.

Dry Creek Habitat Enhancement Feasibility & Alternatives Analysis, & Detailed Design

Dry Creek has been managed intensively for forestry, agriculture and gravel mining since the 1850s, resulting in 25 feet of channel incision. Since the mid-1980s, Dry Creek has also been highly regulated for flood control and water supply. The terms of the effective biological opinion for flood control and water supply operations in the Russian River system include substantial habitat enhancement in Dry Creek, with a target for enhancement of 6 miles of habitat in a 14-mile study reach. The habitat enhancement is focused towards ESA-listed coho salmon and steelhead trout. Since 2007, our work has included:

  • Feasibility and alternatives analysis study along a 14-mile reach.
  • Survey, habitat unit inventory, hydrologic analysis and hydraulic modeling, feasibility and alternatives analysis, project identification and prioritization.
  • Designed and constructed the Dry Creek Demonstration Project, which included habitat enhancements over a 1.1-mile reach (constructed 2012-2014).
  • Initiated design of an additional mile of projects which began construction in 2016 and are expected to be completed in 2018.
  • Begun design of a third mile of enhancement work be constructed starting in 2018.
  • Development of illustrative handbooks used to communicate designs with the community.
  • Extensive collaboration with stakeholders, resource agencies, and community and the US Army Corps of Engineers.

Dry Creek Valley is a renowned wine producing region in northern Sonoma County, California where more than 150 winegrowers and 60 wineries are located. (Photo Sonoma County Watershed Agency)

Detailed habitat and geomorphic field assessment helped develop our understanding of current conditions in Dry Creek.

Bank failures resulting from 20 ft+ of channel incision threaten infrastructure and contribute fine sediment.  Photo: before construction.

Project elements include bioengineered bank stabilization, constructed backwaters and side channels, installation of boulders and log jams, and riparian restoration.

Our bioengineered solution involves intensive revegetation to improve riparian ecology and future bank stability in addition to large wood that provides fish habitat in the channel.

Constructed off-channel habitat provides critical summer and winter habitat for ESA-listed coho and steelhead. (before)

As riparian vegetation matures, the project realizes additional aquatic and terrestrial habitat benefits.

Working with the Sonoma County Watershed Agency, we developed a handbook to communicate designs to adjacent landowners.

Intensive monitoring of the completed project has shown robust fish use in the constructed habitats.