WAT-2005-01 Turkey Creek Watershed Case Study


A detailed study of nonpoint source (NPS) pollution in the Turkey Creek Watershed in Jefferson County, Colorado. 77 pages. Digital PDF download. WAT-2005-01D

Summary of Accomplishments

Construction Water Erosion Model: Using data collected on soils, vegetation, and topography, the CGS created a Best Management Practices tool that estimates and compares soil loss from different soil types, slope, and practices. Land managers and construction professionals can use the tool to select the most effective Best Management Practices for a site. The tool describes the limitations of typical BMPs recommendations for reducing nonpoint source pollution from construction sites.

Post Construction Water Erosion Model: A river basin scale model was used to compare the impact of land management practices on water and sediment yields in the large, complex Turkey Creek Watershed with varying soils, land use, and management conditions over long periods of time. Tools developed from the model allow planners to assess the effects of growth and development and/or changes in management practices on water quality.

Outreach: The Jefferson Conservation District sponsored a regional workshop on using polymers as a Best Management Practice on construction sites. CGS conducted a technical transfer session, at an international construction industry conference, on using a watershed model to evaluate land-use and water quality in an urban mountain watershed.

Jefferson County hosted numerous open houses during development of comprehensive plans. During these collaborative planning meetings, community organizations, citizens, and local stakeholders viewed project maps showing where development may cause water-quality impacts. In this interactive environment, citizens formulated action strategies and goals for water quality improvement, many of which are now part of county land use plans. Similar meetings with other watershed stakeholders were held.

A 1990 Clean Lakes study found that the ecological health of Bear Creek Reservoir is at risk due to nutrient and sediment loading. At times, the reservoir does not meet beneficial use classifications due to excessive phosphorus and nitrogen loading, algal blooms, potential for fish kills, and elevated concentrations of metals in fish. Phosphorus loading, from point and nonpoint sources, is a key water quality concern. The study also recommends reducing sediment loading into the reservoir.

Monitoring indicates that Turkey Creek is an important contributor to nutrient and sediment loading in the reservoir. Although the Turkey Creek (sub)watershed covers only a small portion (25%) of the Bear Creek Watershed, at times, it contributes over 40 percent of sediment and nutrient loads. The primary source of sediment and nutrient loading is thought to be nonpoint sources from urban development. The major land use in the Turkey Creek Watershed is residential development.