Watershed: Palouse River
Stream Name: Paradise Creek
Date Established: 11/07/2001
Project Status: Complete, ongoing monitoring
Overview
Funding Agency: Department of Environmental Quality
Project Location: Latitude: 46.7552°N Longitude: -116.9579°W
Target Pollutants:
- Sediment
- Temperature
- Nutrients
Waterbody Type(s): Intermittent
Hydrologic Unit Code: 17060108
Description
The streambanks on the site were lacking woody riparian vegetation and the riparian area was managed as a pasture for livestock. Reed canary grass formed a dense monoculture in the stream channel and riparian area. These conditions led to highly erosive conditions for streambanks on the site. Bank slumping was evident. The channel was highly simplified, cut off from the floodplain by steep streambanks, and unshaded. Upstream from the restoration site, Paradise Creek was channelized into a roadside ditch. Channelization, dredging, undersized culverts, and removal of vegetation caused high inputs of sediment and increased water temperature.
The wetlands restoration project at the Willard site was primarily designed to function as a sediment catchment. During November 2001, PCEI’s contractors excavated the 10,000 ft2 wetland area adjacent to the stream channel. The wetland catchment receives sediment-laden water during high flows and allows the sediments to settle out. The catchment banks were sloped to a 3:1 slope and stabilized with geotextile erosion control fabric and riparian plantings. Riparian plantings occurred during Spring 2002. Coconut fiber-filled coir logs pre-planted with herbaceous riparian plants were installed at the toe of the streambanks in areas of high erosion potential. Large woody debris was added to the wetlands to further slow water velocities and increase channel complexity. Fencing was installed to exclude livestock from the wetlands area.
PCEI worked closely with the landowners to design, implement and maintain the wetlands project and riparian plantings. The North Latah County Highway District collaborated on the project by consulting and by replacing an undersized culvert directly upstream of the wetlands. AmeriCorps*NCCC members, Washington State University students, and community volunteers participated in the project by installing streambank stabilization materials, planting riparian vegetation, and performing weed control and maintenance activities. A private individual donated habitat structures.
Previous Conditions
Streambanks along this tributary to Paradise Creek were eroding due to a lack of woody vegetation and steep banks. Reed canary grass formed a dense monoculture, whose shallow root mats did not prevent slumping of the streambank. Thus, streambanks were frequently undercut during heavy storm events. The lack of trees or woody vegetation along this stream segment allowed direct solar radiation to heat the stream water. There were also high levels of sediments in this tributary that added to the sediment loads of Paradise Creek.
