Responsible natural hazard planning by people working in councils includes helping communities manage the risk from hazards such as flooding – now and into the future.
Porirua has experienced significant weather events over the past few years and these have been a reminder of the flooding risks that we live with. To help us plan for the future and understand these risks, people at Porirua City Council are working with Wellington Water to complete computer models of the likely impact of extreme rainfall on most of Porirua's urban areas.
Wellington Water is responsible for modelling the flood depth and producing flood hazard maps across Porirua city. These models show areas where there is at least a 1% possibility that substantial flooding may occur on any given year (known as a one-in-100-year flood risk). The modelling shows localised flooding issues, overland flow paths and stream corridors.
These maps aim to help reduce the impact of flooding in the future by giving us a better understanding of flood events, so we can improve our infrastructure and our planning of how we respond to emergencies.
Flooding information is provided on issued Land Information Memoranda (LIMs) for appropriate properties. Recent changes to the Local Government Official Information and Meetings Act 1987 require any information relating to natural hazard information, including drafts, to be provided on Land Information Memoranda (LIMs).
The flood hazard maps are also incorporated into Porirua City Council’s Proposed District Plan once it is made operative, to ensure that any future developments are undertaken in an informed manner and do not increase the flood risk to surrounding properties.
If you would like more information about the flood modelling process please email [email protected]. If you would like more information about the flood hazard maps and how flood risk will be managed through Council's plan-making process, please contact the Climate and Environmental Planning team at [email protected]
People working at Porirua City Council and Wellington Water are currently in the process of updating and developing flood hazard mapping in various stream catchments throughout Porirua.
Please navigate through the sections below to find out more information and see the latest updates for each of the modelled catchments.
Wellington Water on behalf of Porirua City Council, has created two flood depth maps to show the impacts of flooding in Aotea/Paremata and Whitby/Duck Creek.
In June 2025, Wellington Water and Porirua City Council hosted four community drop-in sessions to confirm whether the preliminary flood depth maps matched the lived experience of people living in these neighbourhoods.
Wellington Water have since updated the flood depth maps to reflect the feedback received in June and these maps are now available to view.
The final flood depth maps can be viewed here: Wellington Water Storymaps [Wellington Water]
Community members are also invited to attend a drop-in session at Pātaka on Saturday 27 September from 10am to 12pm 2025 to view these maps.
The flood depth maps will be used to inform flood hazard maps in the Council’s District Plan. When the flood maps are finalised and proposed to be included in the Council’s District Plan, we’ll be in contact again to keep you updated. If you're interested in receiving the information, please contact the Climate and Environmental Planning team at [email protected].
Wellington Water, at the request of Porirua City, has been working to update the flood hazard maps for Mana and Pukerua Bay catchments to include "overland flow paths".
Overland flow paths carry water from the stream catchment during heavy rain when there is too much water for the pipe network or if it is blocked. All stormwater networks are designed to include overland flow paths.
The flood hazard modelling has now been updated to include overland flow paths.
We will be providing this information to you in draft form on your Land Information Memorandum (LIM). This is to ensure you have early and easy access to all the information available about natural hazards that may impact you. If needed, we can help you navigate this new information, including from draft reports.
When the flood hazard maps are finalised and proposed to be included in the Council’s District Plan, we'll update this page.
Making it easier for people to access the latest information about flooding risk by including it on a property's LIM is a responsible and practical way for councils to communicate the important work of looking ahead and planning for our collective future.
Horokiri, a catchment that discharges into Pāuatahanui, is one that has not been modelled before and there are currently no flood hazard overlays in the Proposed District Plan. This is because there is minimal Wellington Water infrastructure in this catchment.
Council is aware that flood-hazard mapping that is currently being provided on LIMs for this catchment is outdated. We are taking action, with the support of Wellington Water, to construct a flood model for this catchment.
Wellington Water is progressing work with modelling the Horokiri Stream catchment. Wellington Water has contracted Awa Environmental to complete the detailed model build.
As part of the model build, Awa Environmental undertook site visits in July/August 2025 to gather more information and validation of the ground levels and asset data held in Council records.
The information gathered is currently being built into the flood modelling.
People working at Council will provide further updates on this work as it progresses.
Where do I find the flood maps being consulted at present and ready for viewing?
To view the Wellington Water Flood Mapping App click here
By using this app, you accept all terms and conditions outlined here
Following the community drop-in sessions hosted by Porirua City and Wellington Water on the preliminary Aotea/Paremata and Whitby/Duck Creek flood depth maps in June this year, we are providing a drop-in session for people to view the updated flood depth maps following the ground-truthing from the community:
You don’t need to book in to attend, simply turn up. You can chat with our experts, or look at the maps to see the updated modelling.
We look forward to seeing you there.
We jointly held publicly advertised drop-in sessions to discuss flooding in Porirua and to share the preliminary flood maps. The drop-in sessions were held on:
