Managing Stormwater

Flooding on Ngauranga Gorge, October 1997

In managing the network that collects, transports and disposes of stormwater, the Council works hard to reduce the risks of flooding and pollution.

The Council's key objectives are to:

• Eliminate cross-connections
  Cross-connections occur when a property's sewerage is illegally connected to the stormwater network. Because stormwater ends up in the harbour, this can be a major source of pollution. The Council actively works to locate and remove cross-connections.
• Reduce sewage pollution
  Pipe damage and other problems with the sewerage network can pollute the stormwater network. The Council routinely collects stormwater samples for testing. If there is any sewage contamination, we investigate its source and make necessary repairs.
• Increase sewage storage
  The Council has undertaken a programme to provide more storage at sewerage pump stations. This will give more time to fix any problems before raw sewage overflows into the stormwater network.
• Implement Catchment Management Plans (CMPs)
  A catchment is an area where water, particularly rainwater, collects when it follows its path downhill. CMPs help manage stormwater, develop strategies to improve the network and address water quality issues.

A typical CMP addresses flood protection by recommending solutions for:

• pipes or channels that are too small
• areas where a stormwater system is needed
• flood pollution
• other issues, such as construction, that may have an impact on flood protection.

Department Details:
Capacity (Wellington Water Management Ltd)