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Belle Fourche/Cheyenne River Basin (Overview) HUC# 101201, 101202Basin Geography:The Belle Fourche and Cheyenne Rivers of northeastern Wyoming exhibit different hydrology than other regions of the state. Streams are ephemeral or seasonal and not supplied by mountain runoff. Rather, spring snowmelt on the plains, summer thunderstorms and groundwater contribute to variable flows. Two seasonal flow peaks are generally experienced. The Belle Fourche River drains the area north and west of the Black Hills and flows northeastward into South Dakota, The Cheyenne River drains the area south of the Black Hills and flows eastward into South Dakota. Keyhole reservoir on the Belle Fourche has storage for 340,000 acre-ft, mostly for use outside Wyoming. Groundwater is a crucial element of the water supply picture in Northeastern Wyoming although supplies are variable. The Madison, Fort Union, Minnelusa and Lance-Foxhills aquifers are utilized. The effects of energy development on groundwater supplies is one issue of concern. This region has some of the most important reserves of coal in the nation. Minimum pool levels in Keyhole Reservoir are a local recreational issue. Future downstream demands in Rapid City, South Dakota are another concern. Relevant Compacts and Decrees: The Belle Fourche River Compact, of 1943, allocates only 10% of the river's flow at the South Dakota border to Wyoming. All rights prior to 1943 are recognized. Limitations on reservoir size below Keyhole Reservoir are stipulated. A compact on the Cheyenne River was negotiated by Wyoming and South Dakota but never ratified by the Wyoming Legislature. Groundwater compacts between the two states have been discussed. Sources: Jacobs, James & Donald Brosz. 1993. Wyoming's Water Resources. University of Wyoming Cooperative Extension Bulletin B-969, Laramie, WY. pp 4. US Geological Survey. 1985. National Water Summary-Wyoming: Surface Water Resources, Water Supply Paper 2300. pp. 494. US Geological Survey. 1984. National Water Summary-Wyoming: Groundwater Resources, Water Supply Paper 2275. pp. 457. Wyoming Water Development Commission & Wyoming State Engineer's Office. 1996. Wyoming Water Planning: A Report for Updating the Process. Cheyenne, WY. pp.15-6
Index of the Statewide Data Inventory | |||||