Water: Nonpoint Source Success Stories
Protecting Bear Lake -
The Thomas Fork Stream Channel Project
The Thomas Fork Watershed in Bear Lake County, Idaho, and Lincoln County, Wyoming, is a 144,366-acre agricultural watershed near Bear Lake. This geologically old lake, which is one of Idaho's Special Resource waters, has developed unique physical, chemical, and biological characteristics. It has more endemic fish species than any other lake in North America, including five species found nowhere else in the world. Thomas Fork is a major tributary to the Bear River, immediately upstream from its diversion into Bear Lake.
Thomas Fork is a valuable resource to Bear Lake; however, its condition also concerns the Bear Lake Regional Commission. Excessive streambank erosion in the watershed and high nutrient levels in runoff from Thomas Fork and the Bear River have accelerated eutrophication throughout the watershed and lake. Historical data show the increase of phosphorus and nitrogen in the area. Bank erosion is largely the result of earlier channel modifications undertaken to support agricultural land uses. When the natural meander patterns of Thomas Fork were broken, severe down-cutting and unstable streambanks exceeded the river's capacity to restore equilibrium.
Project description lures local landowners Recently, the Bear Lake Regional Commission began to interest local landowners in streambank restoration. Several farmers and ranchers came forward to begin the project, which was funded through Idaho's section 319 program. Initial plans called for regrading a 600-foot section of the streambank to restore the nearly vertical 4 to 10 foot high banks along the stream to a 3:1 grade. Materials removed from the banks were used by area farmers to level the low spots in their fields.
The Bear Lake Regional Commission also obtained a U.S. Forest Service tree cutting permit and, with the help of area farmers and ranchers, cut and transported a number of trees to the site. The trees, approximately 15 to 20 feet in length, were placed in the stream channel in an overlapping fashion as flow deflectors and temporary fish habitat. They were anchored to the streambank using special anchors.
Large rocks and boulders were placed at intervals to also act as flow detectors and to protect willow plantings along the reconstructed banks. After a final grading, the area was seeded with native Sodar grass (a streambank wheat grass), and covered with a thin layer of straw to minimize erosion. The reseeded area was fenced to keep cattle from trampling the banks before the plants could mature and stabilize the banks.
During the summer of 1996, a project review found many fish in the area though none had been recorded before the restoration began. Photographs taken after the construction and during later stages help document the project. Community and area farmers have enthusiastically supported the project; and the site has been, and continues to be, the focus of many watershed tours. Area ranchers, farmers, county commissioners, state legislators, state and federal agency staff, and citizens have visited the site.
Additional work using 319 grants will be completed in 1997. When finished, the project will decrease the flow of nutrients to the Thomas Fork by 25 percent and to Bear Lake by 10 percent. The Bear Lake Regional Commission and the 319 program is slowing the pace of eutrophication in Bear Lake and reducing the impact of human activities on the watershed.
Idaho Department of Environmental Quality
Paradise Creek Restoration -
Trout Return, Citizens Learn
Paradise Creek, a fourth order tributary to the South Fork of the Palouse River, is approximately 19 miles long and drains a 34.5-square-mile priority watershed in northcentral Idaho. The watershed's upper portion is forested with very steep slopes, while the middle and lower portions are largely dryland agriculture with moderately rolling hills. Paradise Creek also flows through the city of Moscow, Idaho, where much of the sinuous nature of the original channel has been modified, that is, lost to channelization.
The Palouse-Clearwater Environmental Institute, using a grant from Idaho's section 319 program, took the lead in rebuilding a 1,200-foot reach of Paradise Creek. The project site is owned by Moscow School District, number 281; several state and city agencies, local conservation districts, and the nearby city of Pullman, Washington, actively supported the project. The Palouse-Clearwater Environmental Institute provided oversight and design, coordinated volunteers, and communicated with the public. Its information and educational program was extensive.
According to plan
Detailed design plans, including a site plan, revetments, plantings, and general erosion controls, were completed in 1994. Because no aerial views of the original channel were available, aerial photographs of an adjacent stream channel were used to provide a meander pattern and flood channel design. The final plan called for widening the channel nearly 200 feet to accommodate a low flow center channel with a 2:1 slope ratio and a floodway channel with a 3:1 slope.
The restoration began in September 1995 with permits from the state and the U.S. Army Corps of Engineers. Within a week, nearly 12,000 cubic yards of earth were moved to create the channel and a five-acre floodplain. Volunteers, including school children, university students, and community members, did much of the rest of the work.
Volunteers from the Palouse-Clearwater Environmental Institute built and demonstrated three revetment structures to stabilize the streambanks. These structures included a 175- foot log crib, a 175-foot rock and root wad, and a 175-foot BioLog . Volunteers also seeded and mulched more than 3,000 feet of stream bank and the five-acre floodplain, installed more than 6,000 feet of geotextiles, and planted more than 750 native plants.
A model for future projects
The new configuration is functioning as designed, and this project has become a model for future restoration work in the Palouse region. Not only are the project's partners pleased with the project, it has also become an educational laboratory for students from the Moscow City School District and the Universities of Idaho and Washington State. Long-term monitoring will help determine how long it takes such projects to fully restore beneficial uses within creeks. In the meantime, the physical evidence at this site points to improved water quality. The restored channel no longer looks like the old, muddy Paradise Creek, and trout have returned to the creek. The restored Paradise Creek now provides a working flood plain and stream channel system in an area frequently ravaged by spring floods, habitat for fish and wildlife, and a sense of community pride in protecting, restoring, and preserving its natural resource.
Idaho Department of Environmental Quality