Our drainage system

Drains convey stormwater run-off to compensating basins, rivers, wetlands or the ocean, and often follow the natural watercourses that existed before any land developments or clearing took place. The drainage system includes roadside drains and pipes and open channel systems.

We manage about 2250 kilometres of rural main drains and 828 kilometres of drains in the metropolitan area, diverting water from more than 400 000 hectares of land and preventing the flooding and waterlogging of approximately 260 000 properties.

Local councils manage most of the smaller reticulation drains of Perth's urban drainage network, with some main drains managed by the Corporation. Elsewhere in the State, urban drainage is solely the responsibility of local councils, although in some cases it is managed by the Corporation.

Our drains convey and dispose of stormwater from 76 catchments in the Perth metropolitan area and from many others in the six South West drainage districts.

Many local authority drains connect into our main drainage catchment area system, although local authorities also have their own drain outlets to rivers and oceans. Other agencies, such as Main Roads of Western Australia, have separate drainage networks that may or may not be connected into our or local authority networks.

Privately owned and local council drains swell the network, discharging water into our system. Eventually, it all flows into rivers, lakes and the ocean, or infiltrates groundwater.