Common Problems at Dams - Obstructions in Outlet Channel

Probable Causes and Possible Consequences	Recommended Actions
Beaver dams, accumulated sediment, and other obstructions placed in outlet channels can back water up into spillway outlets, reducing their capacity. Reduced discharge capacity will cause the reservoir to rise and possibly overtop the dam. Prolonged overtopping can cause dam failure. Standing water in corrugated metal pipes accelerates corrosion	Remove beaver dams, sediment, and other obstructions in outlet channels so water does not back up into spillway pipes. Use extreme caution when attempting to remove accumulated debris during periods of high flow. Keep your distance when removing debris so that you don’t become trapped in flowing water when the flow increases after you remove the debris.

trees and other debris blocking outlet channel

Obstructions in this outlet channel caused the water to backup into the outlet of the principal spillway, increasing the deterioration of the conduit.