Media release: identifying city’s flood hazards kicks off in Wainuiomata

Urban Wainuiomata is the first stage of the most comprehensive flood mapping programme in Lower Hutt’s history to near completion – but it needs the help of local residents to finish the job.

The mapping project covers Lower Hutt’s urban areas and is being undertaken by Wellington Water Ltd, which provides water services and planning for the Wellington Region’s councils. It will be completed in 2021.

Hutt City Council Chief Executive Jo Miller says as Lower Hutt is the most densely populated flood plain in the country and with its history of flooding, the mapping programme will provide crucial data for urban planning, infrastructure investment and civil defense planning.

“The main aim of this work is to protect life and property. So to build resilience in our communities, this information will be critical in showing where we can safely develop land and place infrastructure, where to focus on storm water investment and generally to help more effectively plan for the city’s future.”

The maps depict flooding in one in 100 year and one in 10 year floods. They show where waterways are most likely to breach their banks, where water moves across land during flooding and areas of ponding. The work takes into account the projected impacts of climate change out to 2120.

Later this week, Wellington Water and Hutt City Council staff will take the draft maps to Wainuiomata for local residents to view, ask questions and share their recollections of past flooding.

Ben Fountain Chief Advisor Stormwater for Wellington Water says while the maps are developed to best practice standards and peer-reviewed by independent experts, Wainuiomata residents’ local knowledge will help fine-tune the maps.

“People with a memory of past flooding events can point out where water flowed or settled in their neighbourhoods and properties during past flooding events. This information can then be used to adjust the maps to ensure they’re as accurate as possible, so this is a valuable part of the process.”

The information provided by the maps will be incorporated into the review of Hutt City Council’s District Plan to ensure future developments take account of flood risks and don’t increase the risk to existing properties.

All councils are required to make natural hazard information public. Any property with a history of flooding will have this information added to its Land Information Memorandum (LIM).

Public drop-in sessions where people can view the maps, ask questions and provide their observations and photos of past flooding will be held at the Wainuiomata Intermediate School hall on:

• Thursday 5 December 6pm-8pm
• Saturday 7 December 2pm-4pm.

More information can be found at:  huttcity.govt.nz/floodmapping