Flood Hazard Mapping
Waipā District Council is undertaking a district-wide flood hazard mapping project to help plan for New Zealand’s changing climate, and the adverse weather events climate change could bring.
Extreme weather events – such as a 1-in-100-year event - could become more common as a likely impact of climate change. More frequent intense rainfall may increase the likelihood of rivers flooding and flash flooding when urban drainage systems are overwhelmed.
As a result, councils across New Zealand are required under the Resource Management Act to take a proactive approach to plan for adverse weather events.
This is why we are undertaking a district-wide flood hazard mapping project to better understand the areas that may be at risk of flooding in a severe weather event.
With this information, we will be able to look more closely at the capacity of our current stormwater and other infrastructure to plan what we will need for the future.
Information gathered during the project will identify if the current stormwater infrastructure meets the Council's present Level of Service and is fit-for-purpose going forward. It will ultimately help us to put the guidelines in place to help protect urban buildings against flood risk in the future through a range of mechanisms like the District Plan, bylaws, building and resource consents.
What area is covered?
The urban areas of Te Awamutu, Cambridge, Pirongia, and Ōhaupō were covered under this project.
What are the next steps?
Now that we have completed surveys of individual properties identified through the modelling as potentially at risk of over-floor flooding i.e. those expected to get wet carpets, in an extreme 1 in 100-year rainfall event, we have spoken to property owners who we believe are actually at risk as well as those who have been identified as no longer at risk as a result of the visual assessment.
It’s important to know that if you haven’t been contacted by Council to date, this is because your house is not considered as being at risk of over-floor issues.
We will now be using the modelled results to ensure our stormwater network meets the defined Levels of Service, e.g. road drainage to convey away a 1 in 2-year rainfall event, and to identify assets that don’t meet this level for upgrading through the planned renewal and upgrade projects.
We consider all verified, currently-available flood information and modelling when managing its assets and planning future stormwater network improvements. Decisions on the priority and timing of stormwater upgrade spending are made via our Annual Plan and Long Term Plan processes.
We will also use this latest flood modelling information in the District Plan and on the web viewer to manage new urban subdivision, development and use of land to help mitigate flood risk.
Access the: Stormwater Flood Modelling Tool.