FAQ – Stormwater Terms
Any action that reduces factors such as the level of intensity of peak stormwater discharge, pollutant concentrations or loads, during storms or floods.
The process of sucking up or drawing in of a liquid by a porous substance.
An opening constructed in a structure to permit human access for the purpose of construction, inspection and/or maintenance. This term is replacing MANHOLE.
A system of field gullies, access chambers and underground pipes constructed within private property to convey flows through and from allotments.
A water treatment system utilising wetland processes that do not necessarily reflect the natural environment, and where significantly high levels of maintenance are required to achieve their design performance. Examples may include some constructed sub-surface flow wetlands (i.e. gravel bed biological filters).
A modified stormwater pit fitted with baffles that are specifically designed to encourage heavy sediments and floating debris to remain in the pit.
Also known as a CATCH BASIN or TRAPPED STREET GULLY.
BEST PRACTICE ENVIRONMENTAL MANAGEMENT
The management of activity in a manner that achieves ongoing minimisation of environmental harm through cost-effective measures assessed against the measures currently used nationally and internationally for the activity.
A basin designed to temporarily hold storm or floodwaters, and release such waters in a controlled manner to attenuate outflows. No water is retained within the basin between storm or flood events.
Any stormwater detention management system—basin, parking lot, depressed grassy area, rooftop storage, buried or aboveground tank—used to temporarily detain storm or floodwaters for the purposes of delaying or attenuating outflows from a site or catchment.
A drain that transports stormwater runoff from the 5 shoulders of a road or table drain to a disposal area.
Also known as a SPUR DRAIN, TURNOUT DRAIN or MITRE DRAIN.
A constructed channel or conduit used for drainage purposes.
A shallow, low-gradient, grass-lined drainage channel used to convey and treat shallow, concentrated stormwater runoff. The swale may or may not contain a subsoil drainage system. Grass swales treat stormwater by settling, filtration and infiltration; they remove pollutants such as sediment, grit, nutrients and hydrocarbons.
A grid of metal or other material used to prevent debris 2* from entering a drain or pit while allowing pedestrians
and vehicles to pass safely over the opening.
A grill, grate or other barrier located across a channel or pipes to trap litter and debris. The bars may be vertical, horizontal or angled (relative to the direction of inflow) depending on hydraulic and environmental requirements,
Routine work required to maintain existing works and systems in a safe and functional condition.
On-Site Detention or On-Site Stormwater Detention
The point at which water discharges from a river, creek or other flow line; lake, tidal basin or drainage depression; or pipe, channel, dam or other hydrologic structure.
A structure or wall built across a channel, drain or watercourse to raise the water level to allow diversion or measurement of discharge rate.
Weirs may be either sharp-crested or broad-crested, and may operate in either a state of free discharge, or a submerged or drowned state.