Storm drain

Categories: Architecture stubs | Sewerage | Subterranea | Water streams | Physical infrastructure

A storm drain, storm sewer, stormwater drain (Australia) or surface water (UK) system is designed to drain excess rain and ground water from an area. Storm drains vary in design from small residential dry wells to large municipal systems. They are present on most motorways, freeways and other busy roads, as well as towns in areas which experience heavy rainfall, flooding and coastal towns which experience regular storms.

Ideally, storm drains should be separate from sanitary sewers, though in some places the runoff from storm drains is subjected to sewage treatment when there is sufficient capacity to spare. In these systems a sudden large rainfall that exceeds sewage treatment capacity will be allowed to overflow directly from the storm drains into watersheds via structures called combined sewer overflows.

Building codes vary greatly on the handling of storm drain runoff. New developments might be required to construct their own storm drain processing capacity for returning the runoff to the water table and bioswales may be required in sensitive ecological areas to protect the watershed.

An international subculture has grown up around the exploration of stormwater drains. Societies such as the Cave Clan regularly explore the drains underneath cities. This is commonly known as 'urban exploration', but is also known as 'urban caving' or 'draining' (when in specific relation to storm drains).