Fate and Transport of Metals and Sediment in Surface Water

Principal Investigators

Pierre Julien, Chester Watson, and Brian Bledsoe
Colorado State University

Objectives: This effort will focus on surface water and sediment transport, with an emphasis on the fate and transport of metals in rivers from mining wastes. The main thrust of this two-year proposal is to: 1) develop a predictive scientific methodology for evaluating impacts on resulting from both point and diffuse sources of metal pollution; and 2) improve and develop computer modeling tools for the simulation of point-source and non-point source metals and fine sediment contamination in surface waters. The ultimate goal of our research is to improve our mechanistic understanding of the interaction between heavy metals and fine sediment.

Approach: The study entails: 1) field monitoring of contaminated streams; and 2) computer modeling of advection, mixing and dispersion of fine sediment and heavy metals from point and diffuse sources. The models will be calibrated and tested with field data at a few sites on the 303(d) List. One of the main hypotheses to be tested is the relative importance of riffles and pools in the detention and storage of contaminants and as a potential added mechanism for the dispersion of contaminants in mountain streams. Other sites will be determined in collaboration with the remediation and risk assessment groups of this center proposal, as well as with the Water Quality Control Division of the Colorado Department of Public Health and Environment.

Expected Results: The two most important expected benefits of this research are: 1) an improved understanding of the mechanics of heavy metal fate and transport in mountain streams; and 2) development and validation of numerical models for the simulation of advection, mixing and dispersion of fine sediment and heavy metals in mountain streams. Field measurements will be used to calibrate and test numerical models at several sites where the water quality has been altered by mining waste contamination. Funding is requested to support two graduate students to be supervised by three academic faculty members for a period of two years.

Progress to Date: During year one, soil samples were taken at contaminated sites. Researchers also collected:

• various reports of the remediation projects carried out at the California Gulch operable units 4 and 6;
• AVIRIS data from the U.S. Geological Survey;
• USGS orthophotos downloaded at one-meter resolution from the Terraserver web site;
• a digital elevation model and land use grids obtained at 30-meter resolution;
• GIS line and polygon coverages obtained for the California Gulch basin boundary and channel network at a scale of 1:100,000;
• runoff data for the 2002 rainfall events.

Planned future activities are as follows:

• data on hydrography and soil type at finer resolutions will be obtained;
• digital elevation model pre-processing, watershed and channel network delimitation will be obtained for input into the CASC2D-SED model. The model will be run initially for the 100-year, 24-hour, and two-hour storms; and
• the AVIRIS raster data will be evaluated to determine how to derive pH and metal contents.

Progress Reports

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