Working towards resilience – rainfall flood risks in Porirua

01 / May / 2019

We've been working with Porirua City Council to produce flood mapping of parts of Porirua City vulnerable to flooding, so we can work to prevent floods in the future.

The extreme weather in Porirua over the last few years is a reminder of the flooding risks that we live with in our island nation. To help understand these risks and plan for the future, we’ve completed computer models of the likely impact of extreme rainfall on much of the urban areas of Porirua. Flood modelling helps us identify areas that are likely to be affected by extreme rainfall events. 

These models show areas where there is a 1% possibility of flooding occurring in any given year (known as a one-in-100 year flood risk). The modelling studies identified localised flooding issues, overland flow paths and stream corridors. These maps are based on best practice flood modelling standards and take into account sea-level rise and predicted increased rainfall events. They have been peer-reviewed by an external independent party.

These maps should help reduce future flooding impacts by providing us with a better understanding of flood events improving our infrastructure and emergency response planning. This information will be incorporated into Porirua City Council’s District Plan Review to ensure that any future developments are undertaken in an informed manner and do not increase the flood risk to surrounding properties.

View the flood map here