These are systems constructed by humans to convey stormwater through urban areas without undue damage to property or danger to persons from floods, and to minimise environmental damage to drained areas and receiving waters.
Older systems are combined with sanitary sewer systems, so that both sewage and stormwater flow through the same pipe and channel systems. More recent systems, such as those used throughout Australia, provide separate pipes for sewage and stormwater, although there are many interconnections and leakages between the separate networks.
In the 1980s, stormwater pollution control became part of urban stormwater management in Australia, and in the 1990s, water harvesting of stormwater was introduced. In integrated urban water management, stormwater is considered along with water supply and sewerage, in considering urban water in its entirety.