In northern Idaho, Fish Creek once faced serious problems from sediment washing into the water during storms. The Idaho Department of Environmental Quality added the creek to the state’s Clean Water Act Section 303(d) list in 1996 after monitoring showed elevated suspended solids and concerns about sediment and temperature.Over the following years, local groups, landowners and government agencies worked on roads, streambanks and wetlands to reduce erosion.By 2017, Fish Creek earned the maximum possible 3.0 score for cold-water aquatic life, with monitoring showing healthier habitat and multiple year classes of salmonids, as per a report by the U.S. EPA Idaho Department of Environmental Quality.What caused Fish Creek’s sediment problem?Fish Creek is a tributary of Cocolalla Lake in northern Idaho and part of the larger Lake Pend Oreille watershed. Its 7,281-acre subwatershed is largely forested, with about 6,430 acres used for forestry along with smaller areas of rural residential development.You Might Also Like:The watershed has many landowners, including the U.S. Bureau of Land Management, Panhandle National Forest, Idaho Department of Lands, Idaho Fish and Game, industrial timber companies and private landowners.Water quality monitoring conducted by IDEQ in 1991 and 1992 found elevated total suspended solids in Fish Creek during storm events. The findings led the agency to place the 2.37-mile Fish Creek source-to-mouth assessment unit on the 1996 CWA Section 303(d) list for sediment and temperature.The sediment problem was linked to erosion from roads and unstable streambanks. The excess sediment affected cold-water aquatic life in Fish Creek and also posed problems for downstream Cocolalla Lake.IDEQ later developed the Clark Fork/Pend Oreille Subbasin Assessment and Total Maximum Daily Load document in 2001. The TMDL confirmed the sediment impairment and estimated that sediment loads needed to be reduced by 528 tons per year.You Might Also Like:The target load was 278 tons per year, which would allow Fish Creek to meet Idaho’s narrative water quality standard for sediment.The TMDL implementation plan identified road improvements and streambank stabilization as important ways to reduce sediment entering the creek.How did restoration reduce erosion?Restoration efforts unfolded over many years and involved a number of watershed stakeholders.In 1996 and 1997, the Cocolalla Lake Association helped implement Bonner County’s Stormwater Ordinance and developed a stormwater and erosion-control plan for Fish Creek Road and Cocolalla Loop Road. Improvements were also completed on Cocolalla Loop Road at Fish Creek with support from CWA Section 319 funding.Another major project came in 2009, when the Bonner Soil and Water Conservation District received a CWA Section 319 grant to further improve Fish Creek Road.The work included improving 15 culverts, installing nine new culverts, grading roads, improving ditches, adding erosion-reduction measures and improving road drainage.The Cocolalla Lake Association contributed matching funds and took responsibility for ongoing inspection and maintenance of the culverts.These efforts were part of a broader attempt to address the sources of sediment entering Fish Creek rather than simply responding to the effects downstream.What role did wetlands play?Wetland restoration became another important part of the work.In 2014, the Idaho Department of Fish and Game worked with the Bonneville Power Administration, IDEQ, the Natural Resources Conservation Service, Ducks Unlimited and the Cocolalla Lake Association on a CWA Section 319-funded wetland enhancement project near the south end of the lake.The project restored wetland function across 90 acres and restored more than 700 feet of Fish Creek by diverting the stream into historic, sinuous channels.The work helped reduce sediment, nutrient and temperature loads in Fish Creek. It also improved fish passage, spawning habitat and bank stability.At the mouth of Fish Creek, IDFG also received CWA Section 319 funding for channel improvements designed to restore sinuosity and capture water that had been diverted into a railroad ditch.Off-channel wetlands were added as well. When streamflow rose above bankfull conditions, the wetlands could collect water, slow its movement and allow sediment to settle before reaching Cocolalla Lake.Alongside the physical restoration work, watershed partners carried out outreach and education programs. These included the Pend Oreille Water Festival Environmental Education Program, the Idaho State Forestry Contest, stormwater erosion education and LakeASyst assistance for lakeshore residents.The Cocolalla Lake Association also held monthly and annual meetings to keep watershed stakeholders informed.Did Fish Creek recover?The results became clear through monitoring.Beneficial Use Reconnaissance Program data collected in 2017 showed that Fish Creek fully supported its designated cold-water aquatic life use. The creek received the maximum possible BURP score of 3.0, based on results from macroinvertebrate, fish and habitat categories.Fish monitoring also found multiple year classes of salmonids, including young-of-the-year fish.IDEQ’s five-year TMDL review, completed in 2017, found minimal road-related erosion. The data showed low cobble embeddedness, low percentages of fines and increased channel stability.The agency could not make a precise quantitative calculation of sediment-load reductions because the 2001 TMDL did not clearly explain how its sediment loads had originally been calculated.Instead, IDEQ considered the BURP results, other ecosystem information and evidence that nonpoint-source pollution controls had been implemented.Taken together, that evidence showed that the sediment reduction goals had been met. IDEQ determined that Fish Creek was supporting cold-water aquatic life and salmonid spawning uses.The creek was subsequently removed from the state’s impaired-waters list for sediment in the 2018/2020 Integrated Report, with the waterbody information identifying 2020 as the delisting year.The restoration did not end every water-quality concern. Fish Creek remains listed as impaired for temperature pending future review.Still, the progression from the sediment problems documented in the early 1990s to the maximum 3.0 cold-water aquatic life score in 2017 shows the results of sustained restoration work across the watershed.FAQsWhy was Fish Creek listed?Excessive sediment from erosion.What score did Fish Creek earn?A maximum 3.0 BURP score.