Minimum Stream Flow

The complete GIS representation of state-protected waters includes three datasets: Minimum Lake Level, Minimum Stream Flow (Lines) & Minimum Stream Flow Points. Idaho's Minimum Stream Flow Program was approved by the Legislature in 1978 to preserve stream flows and lake elevations for public health, safety, and welfare. The minimum stream flow is the amount of flow necessary to preserve desired stream values, including fish and wildlife habitat, aquatic life, navigation and transportation, recreation, water quality, and aesthetic beauty. Minimum stream flow water rights are held by the Idaho Water Resource Board in trust for Idaho citizens (Idaho Code, Title 42, Chapter 15). Any person or entity can make a request to the Idaho Water Resource Board to file an application for stream flow on any water body within the state. To be approved, a minimum stream flow water right must be in the public interest, must not adversely affect senior water rights, must represent the minimum flow and not the desirable flow, and must show the flow is capable of being maintained.