Nearly 4,000 miles of Montana streams are dewatered each year. This is not the result of drought, rather an inefficient method of allocation. Water allocation in the west is defined by prior appropriation where priority use was given to the first water users leaving what remained for subsequent claimants. The right is maintained by annually diverting the water for use. The right to any water left unused risks being lost. Sharing or transferring the water right was historically prohibited.
While working with ranchers to enhance instream flow, Pat Byorth, a fisheries biologist turned lawyer with Trout Unlimited, began to understand the legal complexities of trout habitat. Farmers that left water instream risked losing the right and the economic value of it. To help the trout the law had to change.
Montana, among other states, now allows water trades and rights to instream flow. The right to transfer water through sale or lease encourages cooperation and consideration of alternative use values. Concern over lost habitat from low water on Wasson Creek in Montana, for example, led Trout Unlimited to partner with an adjacent ranch. Under the new law, rather than risk losing their water right, Mannix Brothers Ranch was able to skip late-season irrigation and leave water instream. In return, the ranch was compensated to cover the lost pasture production creating a win-win deal for both fish and farmer. The emergence of environmental markets for water is helping rewater the west.