|
North Platte River Basin (Overview) HUC# 101800Basin Geography:The North Platte River Basin in Wyoming is the most densely populated in the state. The river and its tributaries, the Encampment, Sweetwater, Medicine Bow and Laramie, drain most of the southeastern quarter of Wyoming. The basin covers about 28,000 square miles. The North Platte originates in the mountains of Colorado and flows north towards Casper, Wyoming where it turns towards the southeast and eventually flows into Nebraska. Several tributaries drain mountainous areas on the eastern continental divide. Five mainstem federal reservoirs, managed by the U.S. Bureau of Reclamation, have a combined capacity of over 3 million acre-ft to store spring runoff. This storage serves instate and Nebraska irrigators. About 528,000 acres are irrigated in Wyoming. The Laramie River also originates in Colorado and flows north to join the North Platte near Wheatland and has reservoir regulation of flows and extensive irrigation use. Wyoming depletes about 800,000 acre-ft of the North Platte River Basin surface flows; two-thirds for agriculture. Agricultural, industrial, and recreational uses of the river are widespread. Nationally recognized fisheries exist in the cold waters downstream of reservoirs. Natural selenium contamination of wetlands is a concern near Casper, as is groundwater contamination from industrial sites. In Goshen County, intensive agricultural production has led to groundwater vulnerability from agricultural chemicals. Groundwater control areas have been established by the State Engineer's Office because of the drawdown of aquifers in the Ogallala Formation. Relevant Compacts and Decrees: Wyoming's rights to use waters of the North Platte and Laramie Rivers are governed by U.S. Supreme Court decrees. The Laramie River decree of 1922 was amended in 1957 and specifies the diversions allowed in Colorado before the Laramie flows into Wyoming. All waters in excess of 49,375 acre-ft are allocated to Wyoming. The North Platte River Decree of 1945 was amended in 1952. The decree outlines complex limits to flows, storage and irrigated acreage in the Wyoming portion of the North Platte River Basin. The river is considered to be fully allocated. In 1986, Nebraska v. Wyoming re-opened this decree on the basis of eleven separate management issues. Leading issues included reservoir construction in Wyoming, conjunctive groundwater use in both states, endangered species in Nebraska and Wyoming's adherence to the 1945 decree. Presently, a cooperative agreement has increased negotiations between the two states and Colorado in a search for solutions. Wyoming has spent over $17 million defending its case and attempting to correctly define hydrologic conditions on the river. The Supreme Court case is still unresolved. Sources: Wyoming Water Development Commission. 1990. Wyoming Water Atlas. University of Wyoming, Laramie. pp. 47. US Geological Survey. 1985. National Water Summary-Wyoming: Surface Water Resources, Water Supply Paper 2300. pp. 494. US Geological Survey. 1986. National Water Summary-Wyoming: Ground-Water Quality, Water Supply Paper 2325. pp. 541. Wyoming Water Development Commission & Wyoming State Engineer's Office. 1996. Wyoming Water Planning: A Report for Updating the Process. Cheyenne, WY. pp.17-20
Index of the Statewide Data Inventory | |||||