Investigations in Western South Dakota and Northeastern Wyoming

The field work on which this report is based was carried out during the summer of 1948 by a field unit of the Missouri Valley Project, River Basin Surveys, Smithsonian Institution. The unit consisted of Mr. J. M. Shippee and myself; we were assisted during part of the time by Messrs. H. F. Wilson, S. J. Phelps, and R. F. Worden of Hot Springs, South Dakota. Investigations covered the four-month period from June 1 through September 29.Five proposed reservoir sites in the Cheyenne Basin were investigated more or less intensively. All are Bureau of Reclamation projects, in various stages of development, located in or near the Black Hills of western South Dakota and northeastern Wyoming. Angostura Reservoir received much more thorough exploration than the others; work at this site forms the basis for the present report. Edgemont and Keyhole reservoirs are omitted because the data from them have not yet been evaluated. Pactola and Johnson Siding reservoirs, alternate projects, were unproductive and require no discussion.