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Best Practice Guideline 1 - Stormwater Outlets
Introduction
The purpose of this guideline is to provide information on the construction of stormwater outlets and spillways to minimize erosion and damage to riparian habitats and foreshore banks from stormwater outflow into watercourse and on waterfront land.
This Best Practice Guideline applies to all stormwater outlets from all infrastructure including roads, buildings, constructed basins/wetlands, swales or other drainage works.
Locations of existing stormwater outlets that are directed into the Pittwater Estuary and its tributary creeks are available on request to Pittwater Council.
Brief outline of the process involved
- Identify the specific point of discharge and wherever possible, select a rout along an existing cleared or disturbed area.
- Choose a stable section of the stream mid-way between bends or incorporate outlet discharge points into disturbed/eroded areas which are to be stabilized/rehabilitated
- Discharge velocities and flow rates should mimic existing natural flows to minimize erosion, bank stability and other detrimental impacts to the foreshore banks and bed
- Outlet should direct flows downstream and avoid ‘jet’ effects on the adjacent stream banks
- Rock rip-rap is the preferred material to provide a natural outlet and should cover the full extent of the design scour apron (including adjacent banks if required). The outlet must align with the existing bank
To access the full details of the Best Practice Guidelines click here
Further Reference
- Guidelines for controlled activities – Outlet Structures (Water Management Act 2000)
- Assessing the habitat values of stormwater drains in coastal areas
- Managing Coastal Stormwater drains for fish habitat
- Retrofitting coastal stormwater drains using water sensitive urban design principles
- Preparing a stormwater drain management plan in coastal areas
