When most people think of a "run-of-river" power project they visualize a free-flowing river with a small turbine generating electricity. The reality is far different. Typically, up to 80-90 percent of the mean annual discharge of a river is diverted into a pipe, which channels water downhill for several kilometers to a turbine where electricity is generated and the water returned to the ecosystem. Natural seasonal fluctuations in river flow will be blunted and there will be fewer aquatic insects, and less gravel and woody debris, all of which negatively impact stream health.