Operation of the Garrison Diversion Unit in North Dakota will divert water from the Missouri River near Lake Audubon into the upper James River basin (fig. 1). The diverted water will augment flows in the James River sufficiently to permit expanded irrigation and to provide additional water supplies for municipal and industrial use. The proposed Garrison Diversion Unit development and associated expanded irrigation has caused environmental concerns regarding potential mobilization, transport, and concentration of potentially toxic trace elements. In order to address'these concerns, a study of trace elements was made cooperatively by the U.S. Bureau of Reclamation and the U.S. Geological Survey during 1986-88. The traceelement study area consists of approximately 130,000 acres and includes the Turtle Lake, Lincoln Valley, Harvey, New Rockford, LaMoure, and Oakes areas. As part of this study, Severson and others (1988) reported on the baseline geochemistry of soils, with special emphasis on selenium, for an irrigation test area of about 15 square miles near Oakes, N.Dak. This report presents the water-quality data collected during December 1986 through September 1987 from selected wells and drain sites in the Oakes study area.
