How the Christchurch City Council responds to wet weather and flooding events.

Flooded park

We're always monitoring weather, rainfall and tide forecasts so we can be well prepared for any rain event that might cause flooding. 

When wet weather is forecast to cause flooding we take action before and during flooding to reduce the impacts on our city.

What we do to keep our community safe

During significant wet weather and flooding events staff from our Transport, Three Waters, and Civil Defence and Emergency Management teams are available round the clock to respond to issues. They're also out and about keeping an eye on our roads and infrastructure.

Transport 
  • Close roads as required. You can find out what roads are closed on Facebook(external link). 
  • Put up signs and cones to warn of flooding and divert traffic. 

Infrastructure
  • Monitor vulnerable areas and ensure stormwater infrastructure is clear and working. 
  • Clear large stormwater pipes that discharge to our coastline. 
  • Clear grates that are critical to our stormwater network. 
  • Close the stormwater retention basins at the top of the Heathcote River to store stormwater and reduce flooding. 
  • Use temporary pumps in key locations to support our stormwater network. 
  • Where possible, clear slips and landslides caused by flooding. 

Health and wellbeing
  • Work with Te Whatu Ora - Health New Zealand to monitor flood water contamination. 
  • Keep the public informed about how wet weather and flooding are affecting our district.

Stormwater retention basins

We have stormwater retention basins within the upper Heathcote River catchment. In periods of regular rainfall, the gates to the basins remain open and water flows through the basins and into the river as normal. 

When significant rain is forecast we close the gates between the basins and river as rain begins. Stormwater collects in the basins limiting the amount of water flowing into the Heathcote River and reducing flooding. 

Once the rain subsides we slowly release the water that has amassed in the storage basins. We do this to make room in the basins in case we get more rain. 

Wetlands

We’re building a series of new working wetlands across Christchurch to capture and naturally treat stormwater. The Sparks Road and Curletts Road wetlands are already complete and play a significant role in our stormwater network. 

Wetlands help reduce the risk of flooding, improve water quality and include beautiful new recreational spaces for our communities to enjoy and interact with nature. They are stormwater treatment facilities that capture and naturally filter stormwater from the local neighbourhood before it flows into our rivers and streams.

Wetlands help reduce the risk of flooding during heavy rainfall by capturing excess rainwater. This water is slowly released, reducing downstream flooding.