The Snake River is an interstate river with waters subject to laws of five states and the federal government. The flows and levels of the river in Washington state are heavily influenced by the operation of federally owned and federally licensed dams located upstream from Washington and within Washington, as well as by water diversions in the various states. The waters of the river support extensive irrigation, navigation, municipal, industrial, and power generation uses as well as nationally significant anadromous fish runs. These fish runs require for their survival clean, flowing water assured by minimum flows and special actions by all agencies sharing in the management of the river.

The department of ecology of the state of Washington recognizes that, under our federal constitutional system, regulatory power over the Snake River is shared between the United States and the states and that by various federal actions the state's powers may in some cases be superseded through the mandates of the Supremacy Clause of the United States Constitution.

This chapter is adopted to promote the proper utilization of the water resources of the Snake River and to protect and insure the viability of the instream resource values associated with the main stem of the river in the future.