Drainage Terms A-Z
O
off-line tank
Detention tank that is off the normal path of flow in a network, which comes into operation during periods of high flows.
on-line tank
A detention tank through which the flow of sewage is normally conveyed.
orifice
A constriction in a pipeline to control the rate of flow.
outfall
The point, location or structure where wastewater or drainage discharges from a pipe, channel, were, drain or other conduit.
overflow
The intentional or unintentional discharge of sewage to the environment before it has been treated.
overflow weir
Any device or structure over which any excess water or wastewater beyond the capacity of the conduit or container is allowed to flow.
overland flow
The flow of water over the ground or paved surface before it enters some defined channel or inlet, often assumed to be shallow and uniformly distributed across the width. |
