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Part I: Urban Design Guidelines for All Subdivision and Development in the District


9    Infrastructure


9.1    Stormwater Management and Low Impact Design

Stormwater run-off within a catchment must be carefully managed to avoid (often cumulative) problems of flooding, erosion and pollution of water bodies. Stormwater systems should reduce stormwater flow and optimise interception, detention, and removal of waterborne pollutants from urban run-off before they are discharged to receiving waters.
If stormwater disposal is managed sustainably, there is less impact on the environment and lower longer-term maintenance costs. Stormwater management can provide attractive amenity features within and adjoining subdivisions.


Paved surfaces should be carefully controlled to reduce the number of water-resistant surfaces and resulting increases in stormwater run-off. Using narrower carriageways and semi-permeable paving (paving that will absorb some water) for on-road parking can help to reduce this issue. Wetlands or marsh areas and larger grass verges can allow groundwater recharge, slow the movement of water, and reduce pollutants in receiving water bodies.


Developers should consider the following design elements:

  • Ensure that post-development flows are restricted to pre-development levels using a suitable variety of stormwater methods within lots and throughout the drainage network.
  • Reduce stormwater discharge to reticulated networks by the use of street-edge wetlands and rain gardens to collect stormwater run-off from paved surfaces and provide onsite water storage.
  • Improve the quality of stormwater before it reaches streams by allowing it to flow over grass areas (such as swales and through constructed wetlands).
  • Consult with an engineer to determine the most appropriate solutions to address the site’s topography, soil types and ability to dispose of stormwater through groundwater recharge and soakage.
  • Encourage the detention and re-use of stormwater within each lot. Rainwater harvesting from dwelling roofs can significantly reduce the amount of stormwater discharged during storms.
  • Encourage single car-width driveways and vehicle crossings to reduce impervious surfaces.
  • Carefully design wetlands and ponds to avoid water quality problems.
  • Carefully select vegetation as some can become weedy and choke waterways.
  • Make use of permeable paving and landscaping.