Muddy Creek, a tributary to the Little Snake River, is a semi-arid catchment that drains about 1,200 mi2 in south-central Wyoming. The drainage basin is characterized as a sagebrush steppe ecosystem. The area is undergoing energy exploration and development, including conventional natural gas wells and coalbed natural gas wells. Geologic formations that underlie the drainage basin include soluble marine shales, which are a natural source of dissolved solids (for example, sodium, chloride, and sulfate) and Se. As a result, the water quality of Muddy Creek is naturally high in dissolved constituents, including Se. The WDEQ has listed chloride and Se as impairments to aquatic life for Muddy Creek. Dissolved solids are a concern also because [...]
Summary
Muddy Creek, a tributary to the Little Snake River, is a semi-arid catchment that drains about 1,200 mi2 in south-central Wyoming. The drainage basin is characterized as a sagebrush steppe ecosystem. The area is undergoing energy exploration and development, including conventional natural gas wells and coalbed natural gas wells. Geologic formations that underlie the drainage basin include soluble marine shales, which are a natural source of dissolved solids (for example, sodium, chloride, and sulfate) and Se. As a result, the water quality of Muddy Creek is naturally high in dissolved constituents, including Se. The WDEQ has listed chloride and Se as impairments to aquatic life for Muddy Creek. Dissolved solids are a concern also because Muddy Creek is part of the Colorado River Basin, where salinity control has been a concern for decades. The overall goal of this multi-disciplinary, synoptic study has been to evaluate watershed processes as a means of understanding how land-use changes may affect the occurrence and distribution of dissolved solids and Se in the Muddy Creek drainage basin.
To characterize concentrations of major ions, Se, and other trace element in surface water, groundwater, soil, bed sediment, and in aquatic and riparian insects, samples were collected during the 2010 and 2011 field seasons. In FY2012, sample analyses were completed and products were drafted. Results indicate that water chemistry of Muddy Creek varied spatially, with dissolved solids (including sodium, chloride, and sulfate) generally becoming more concentrated from upstream to downstream. Dissolved solids and Se concentrations in samples from the drainage basin generally were elevated in areas underlain by marine shales. The chemistry of groundwater samples from flowing wells was dominated by sodium and bicarbonate, and generally the concentrations of trace elements that are more soluble under reduced conditions (such as iron) were greater than they were in stream samples. In contrast, concentrations of other trace elements (such as Se) tended to be greater in stream water than in groundwater samples. Overall, results suggest that the dissolution of mineral salts at or near the surface is an important process controlling the stream chemistry in the Muddy Creek watershed.
Holloway, J.M., Bern, C.R., Schmidt, T.S., McDougal, R.R., Clark, M.L., Stricker, C.A., and Wolf, R.E., 2012, Evaluating natural gas development impacts on stream ecosystems in an Upper Colorado River watershed, presented at the Wyoming Landscape Conservation Initiative Science Workshop, May 15-17, 2012, Rock Springs, Wyo.
Holloway, J.M., Bern, C., Schmidt, T.S., McDougal, R.R., Clark, M.L. Stricker, C.A., Wolf, R.E., December 2011, Evaluating natural gas development impacts on stream ecosystems in an Upper Colorado River watershed: EOS, Transactions of the American Geophysical Union, v. 92, Fall Meeting Supplement, Abstract H31A-1124.
Schmidt, T.S., Wolf, R.E., Stricker, C.A., Holloway, J.M., Bern, C.R., Clark, M.L, and McDougal, R.R., 2012, Riparian consumers as indicators of aquatic contaminants: Society of Freshwater Science Annual Meeting, Louisville, Ky., May 20-24, 2012, at http://www.sgmeet.com/sfs/sfs2012/viewabstract2.asp?AbstractID=6837.
Products Completed in FY2011
Holloway, J.M., Bern, C., Schmidt, T.S., McDougal, R.R., Clark, M.L. Stricker, C.A., and Wolf, R.E., 2011, Evaluating natural gas development impacts on stream ecosystems in an Upper Colorado River watershed: American Geophysical Union, Fall Meeting 2011, abstract (submitted for a poster to be presented in late fall 2011; now available online at http://adsabs.harvard.edu//abs/2011AGUFM.H31A1124H).
