Managing stormwater

Stormwater is rainwater running off surfaces including lawns, roads, roofs, car parks and natural ground. We maintain stormwater infrastructure to drain rainwater and prevent flooding in built-up areas. Stormwater is not wastewater – it flows into our waterways untreated.

We maintain over 2800 kilometres of underground stormwater pipes and 490 kilometres of surface drains. Each year we implement a range of projects to maintain and upgrade our stormwater infrastructure to:

• improve safety and functionality of stormwater systems
• reduce flood risk during rainfall events
• improve water quality
• reduce ongoing maintenance requirements and costs.

Stormwater drainage

Landholders and developers are legally responsible for managing stormwater runoff from their properties. For information visit Stormwater drainage.

Water sensitive urban design

This approach to planning and design of urban environments supports healthy ecosystems through smart management of water.

As part of our urban sensitive design approach, we maintain over 1700 devices which improve the quality and control the flow of stormwater runoff into the city's creeks and channels. These include:

• Gross pollutants traps – physical structures to trap solid waste including litter and coarse sediment.
• Bioretention basins – densely vegetated basins to filter runoff during rain.
• Constructed wetland systems – shallow, extensively vegetated water bodies usually connected to a waterway. Water flows into the systems during rainfall events and is slowly released back into the waterway. In addition to treating stormwater, constructed wetlands can also provide habitat and recreation.
• Sedimentation basins – basins temporarily capture stormwater runoff to allow sediment to settle out of the water. These devices are extremely expensive to build and maintain and are only a small part of the solution. They treat the problem, but they do not fix it.

Stormwater drainage and water sensitive urban design standards are applied to new development and other activities through the City Plan.