There are three hydroelectric facilities operating in WRIA 1. Other projects have been proposed, and are in various stages of local and Federal Energy Regulatory Commission permitting. The existing and proposed facilities are "run-of-the river" design, which takes advantage of natural elevation drop by diverting water into a pipeline that is run downhill to increase the head, or the vertical distance that the water falls, which in turn increases the amount of power generated. Typically, the water is then returned to the stream from which it came. When stream flow is diverted into a pipeline, the stretch of the stream between the point of diversion and where the water is returned to the stream is called the bypass reach. WRIA 1 does not have any facilities that use a dam and reservoir to create an artificial change in a river's elevation, which are known as "high-head" facilities. A 1950s study by the U.S. Army Corps of Engineers did not find any sites within WRIA 1 for high-head hydroelectric projects that were financially feasible.