Hydraulic Cleaning

Techniques and methods used to clean sewer lines with water e.g.: water pumped in the form of a high velocity spray and water flowing by gravity or head pressure. Devices include high velocity jet cleaners, cleaning balls, and hinged disc cleaners.

Hydraulic Grade Line (HGL)

See Hydraulic Gradient.

Hydraulic Gradient

An imaginary line through the points to which water would rise in a series of vertical tubes connected to the pipe. In an open channel, the water surface itself is the hydraulic grade line.

Hydraulic Radius

The area of the water prism in the pipe or channel divided by the wetted perimeter. Thus, for a round conduit flowing full or half full, the hydraulic radius is d/4, Another term sometimes used for this quantity is hydraulic mean depth.

Hydraulic Reinforcement

The provision of an additional sewer which in conjunction with an existing sewer increases overall flow capacity.