WHAT’S HAPPENING WITH TODAY’S DAMS

This 96-inch jet flow gate valve is installed in Hoover Dam.

Hoover Dam replaced all 16 of its first generation 84-inch and 96-inch needle-type regulating valves and their companion cast “Paradox emergency gate valves” in 1998 because of safety concerns. The Paradox block valves were in line upstream of each needle valve to allow for the maintenance of the complex needle valves when required. All those valves were replaced with fabricated jet-flow valves.

Some reservoirs may use a form of globe valve located in a valve house in a deep part of the lake near the dam. These inlet structures offer a path for water to pass through the dam differently than over its top or through sluice gates. In the simplest of dams, this may be only a passive intake pipe open to the top to allow water over a certain depth to bypass the dam and flow through piping to the other side of the dam structure.

While the valves in a simple reservoir-only dam may be rudimentary, the valving in a large hydroelectric dam can be extensive and unique because of how the water flows through the dam and through turbines to create electricity.