CTWS Side Channel Restoration Implementation

Historically, the Clackamas River supported some of the most diverse and productive fish populations in the Columbia River Basin. Today, the Clackamas River still supports regionally significant fish runs. However, fish populations in the area have declined from historic levels, with some fish runs diminished to the point of being listed as “Threatened” under the federal Endangered Species Act (ESA). Despite dramatic growth and development, the region still supports a rich diversity of fish and wildlife habitats. Rivers and streams within the Clackamas River basin support some of the healthiest salmon populations in the region. The Clackamas River basin, for example, has the last vestige of a native wild late-run Coho salmon (Onchorhynchus kisutch) population in the lower Columbia Basin. Today, the late run Coho generally spawn on the mainstem of the Clackamas above the North Fork Reservoir. The Clackamas late-run Coho differ from other local hatchery influenced Coho runs because of their large body and egg size, spawn timing, and spatial segregation from other Coho. In addition to Coho, the Clackamas spring Chinook salmon (O. tshawytscha) population is trending in a positive direction due to new fish passage facilities at the dams east of Estacada on the upper mainstem Clackamas River. Overall, the prospects for salmon and steelhead (O. mykiss) in the Clackamas River basin are promising, but substantially more habitat restoration and increased productivity is needed to meet salmon and steelhead recovery goals and sustain the environment that supports native fish and wildlife populations.


The CTWS side channel restoration project is located in the mainstem Clackamas River approximately 8 miles upstream of Ripplebrook. More importantly the project is located several miles downstream of the Big Bottoms reach, the most important salmon spawning habitat in the upper Clackamas and one of the most intact spawning reaches in the Willamette drainage. The project will improve fish habitat in multiple locations along a one mile stretch of the river, including placing apex/mid channel log structures to bring water to side channels which are especially important rearing and spawning areas in the project reach. The roughly 7-acre unauthorized camping and parking areas will be graded, decompacted, loaded with large wood and boulders, eradicated of weeds, and replanted with native seed, plants, and shrubs.


The overall goal of the proposed project is to increase the abundance and productivity of Clackamas River Basin ESA-listed salmon and steelhead populations by accelerating the recovery of naturally functioning conditions within instream and side-channel portions of the mainstem Clackamas River. Excavating and grading of several low terraces to create additional side and off channel areas will increase the amount and quality of habitat for juvenile salmonids. Adding woody debris instream (and in side-channels) is a common strategy to enhance fish populations, and increases habitat complexity, provides food or habitat from prey species, reduces water velocity, increasing stream depth and pool frequency. Grading and restoring the impacted riparian areas at the site will improve water quality by increasing shade, reduce the delivery of fine sediments from the unapproved camping areas and reduce the amount of trash and human waste that reaches the river.


Worksite #1 Proposed Work:

Increase the quantity and quality of side and off channel areas at the site by excavating, grading, adding large wood and replanting. Increase large wood abundance in a one-mile reach of the Clackamas River. Increase connection to the floodplain and create complex mainstem habitat on 7 acres. Revegetate areas disturbed by the unauthorized camping and loitering as well as vegetating areas disturbed by the construction and grading actions of the project.


* Note: This project replaces the previous project 19-Warm-02, w

Clackamas River basin ESA-listed fish species; Spring Chinook, Lower-Columbia River Coho and Lower Columbia River steelhead are negatively impacted by loss of habitat, impaired water quality and lack of access to historic spawning areas, such as side channels. This project will restore habitat elements believed to be most limiting to these populations of salmon and steelhead.


Lack of Large Wood: Limited pieces of large wood were noted by surveyors within the active channel area of the project reach. A lack of mature conifers within the riparian and upland areas limits future recruitment of large wood from those areas and it is likely there is little recruitment from upstream reaches given that the highway continues as you travel upstream of the project area. Large wood, especially key pieces are an important component of creating and maintaining physical habitat diversity for the ESA-listed fish. Significantly increasing the density of large wood in the project area would greatly enhance biological conditions for these fish. Large wood creates hydraulic roughness along the channel and, in turn, recruits gravels needed for spawning fish. Spawning fish depend on appropriately sized gravel and cobble that are not always found in a river devoid of the roughness provided by instream wood. Rearing salmonids also depend on in-stream and overhead cover for refuge from predators. Large wood provides refuge for juvenile salmonids, as well as a substrate where food resources tend to accumulate, in the form of macroinvertebrates.


Loss of Side and Off Channel habitats: This project will directly benefit the salmonids by greatly increasing the amount and quality of side and off channel habitats at the site. The hot springs side channel will be enhanced by removing the user created water control structures and addition of large wood. Two new side channels will be excavated into low flood plains between the river and FS46 creating ~2,000 linear feet of side channel habitat. Two existing off channel areas will be loaded with large wood which is currently lacking in the reach.