Stan Church, Task Leader
Historical metal mining in the study area has been locally extensive and has affected water and sediment quality, riparian function, and fishery productivity in many areas. Evaluation of the extent and nature of these types of impacts is required by Federal statutes of the Clean Water Act to mitigate Federal lands and is an important component to this project. Both mined and unmined mineralized rocks in the Colorado mineral belt may create high background values of sulfate and potentially toxic metals that degrade surface water during weathering. A goal of this project is to develop a protocol that allows the identification of areas that may be problematic and to characterize the effects of sulfates and toxic metals on both the water quality and aquatic life in watersheds. Regional sampling is underway to characterize water, biofilm, and sediment chemistry, and how they affect aquatic biology, in the headwater regions of three types of basins: (1) those that have seen no historic mining activity, (2) those that are hydrothermally altered but not extensively mined, and (3) those that were extensively mined. Basins for these studies were selected using GIS-based queries of digital geologic maps, digital elevation models, and basin-area calculations. The biological investigations are a collaborative effort with biologists from Colorado State University, who will be conducting studies of macroinvertebrates at sample sites.
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Sampling macroinvertebrates (above left) and streambed sediments (above right) to investigate the influence of bedrock on the geochemistry of aquatic and riparian systems. |
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U.S. Department of the Interior | U.S. Geological Survey
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