Court Decrees & River Compacts

Before Wyoming became a state, when settlers first moved to the west, water rights were established. When water users disagree about how much water each one is entitled to a court or judge decides which is in the right, or how much water each party is allowed to use. The involuntary water agreements that result are called court decrees. They contain the same information as a compact but are not the result of negotiation of water users but the decree of a judge or judges. Wyoming has three court decrees that manage interstate water use. These decrees only deal with bordering states by circumstance not definition.

Interstate Compacts and Decrees for Wyoming's River Basins

River Decree, 1957

The Laramie River begins in north central Colorado and quickly enters Wyoming where it flows north along the Laramie mountain range in Albany county before heading west through the range and across to Goshen county where it meets the North Platte River at Fort Laramie. Colorado is restricted from using more than 19,875 acre-feet per year from the Laramie River, the remainder of which must flow into Wyoming. Stipulated by the North Platte River Decree Wyoming is not allowed to irrigate more than 39,000 acres from the Laramie River below Wheatland Number 2 Tunnel.

North Platte Decree, 2001

The North Platte River Begins in the Colorado Border County of Jackson and flows north into Wyoming. The North Platte River then goes north to central Wyoming out of the mountains and curves southeast where it exits the state to Nebraska from Goshen County Wyoming. From there it flows east the width of Nebraska where it meets the Missouri river at the Nebraska-Iowa border. The Supreme Court decided in 1945, 1953, and 2001 a new legal distribution of the water of the North Platte River and how it was to be divided between Nebraska, Wyoming, and Colorado. Of the natural flow of the river between Guernsey Dam and Tri-State Dam Wyoming is allotted 25% for use. Wyoming is not allowed to use more than 1,280,000 acre-feet above Pathfinder Dam and 890,000 acre-feet between Pathfinder and Guernsey Dam in any ten year period.

Roxana Canal Decree, 1941

This decree covers Teton Creek and South Leigh Creek which flow off of the west side of the Teton Mountains a short distance into Idaho and eventually flow into the Henrys Fork River. For Teton Creek, Wyoming water users are allowed unlimited diversions when the flow is above 170 cubic feet per second. Under this threshold 1 cfs is permitted for diversion per 50 acres of land. South Leigh Creek allows unlimited Wyoming water use over 16 cfs of creek flow. When the flow is reduced below 16 cfs Wyoming is allowed to use half of the creek’s flow.

Interstate Compacts

Compacts are agreements between states and water users about how the water in a river or basin will be divided up. They often have many stipulations concerning how much water or precipitation the river has received over a set period of time. There are several ways compacts divvy water. It can be by percentages allowed for withdrawl, set volumes of water allowed for withdrawl, area of land that may be irrigated, amount of water that may be stored, or a combination of any and all forelisted methods. Compacts are legal documents, often written in very complicated and obtuse language which can make it hard to decipher the details or specifics concerning water allocations. Wyoming is party to seven interstate compacts that regulating the use of water coming to or leaving the state. These compacts include all bordering states and many downstream states that do not share a border with the state.

Amended Bear River Compact, 1978

The Bear River starts in the Uinta Mountains and flows north into Wyoming. It passes through Evanston then crosses into Idaho in northwestern Uinta County. The Bear River then reenters Wyoming in southwestern Lincoln County and passes through Cokeville and makes its final exit from the state into Utah. For water use purposes it is divided into three divisions, one of which includes Wyoming. The Upper Division has two Diversion Sections in which Wyoming is allotted water. The Upper section from its original entrance to Wyoming to its first exit of the state into Idaho and the Lower Division section from the Bear River’s reentrance to its final exit into Utah.

Wyoming is allowed by the compact to divert 49.3% of the water in the river in the Upper diversion section and 9.6% of its flow in the Lower diversion section. These restrictions only apply however when the total divertible flow in the Bear River is less than 1,250 cubic feet per second. The State of Wyoming’s southwestern irrigators are also allowed to store 17,750 acre-feet of water in any one year (shared with the Upper Utah Division) and 70,000 acre-feet in any one year (shared with the Upper Idaho Division).

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