The Truckee River is Lake Tahoe’s only outlet. Unlike most major rivers in the United States, it does not flow into the ocean. The Truckee River flows east into Nevada, passing through Reno and ending in the desert at Pyramid Lake, which does not have an outlet but loses water through evaporation. The Truckee River system relies on rain and snowfall in the Sierra Nevada. It receives water from Lake Tahoe and other reservoirs to maintain adequate flow for use in agriculture, for residential and recreational purposes, and for a fresh water fishery.
The system is managed under the Truckee River Operating Agreement (TROA), a federal program that must comply with the Truckee-Carson- Pyramid Lake Water Rights Settlement Act of 1990. The TROA provides procedures for the operation of storage reservoirs along the Truckee River in order to sustain water flows that, among other things, ensure adequate water and habitat for two fish species: the cui-ui (an endangered species) and the Lahontan cutthroat trout (a threatened species).