Flood protection
Flood protection is an area of investment that goes largely unnoticed until it’s needed. In February, in the Wairarapa and Wainuiomata, our infrastructure and response systems were put to the test – and stood up well to the challenge.
The heavy rain and subsequent flooding caused $1.28 million worth of damage in the Wairarapa and $0.44 million worth of flood damage in rivers and streams in the Hutt Valley, Porirua and Kapiti Coast.
However, flood defences generally held up well despite the damage they sustained. The flooding would have been more widespread and damage would have been far grater without the work Greater Wellington has carried out in the past.
The Waiwhetu Stream suffered a 50-year flood, prompting a study of flood protection issues and solutions. Engineers will also review the Lower Wairarapa Valley flood protection scheme using real-life data.
Meanwhile, the 40-year investment programme for flood protection in the Hutt Valley began this year. The Belmont edge protection works will minimise the risk of riverbank erosion for properties close to the Hutt River. Further downstream, preparations are underway for a $4 million river realignment project between the Ava and Ewen bridges. Once complete, the Alicetown stopbank will be upgraded to give those residents greater flood protection.
On the Kapiti Coast, we completed building of the Otaihanga floodwall, providing extra protection to Makora Road residents from floodwaters from the Waikanae River. We also revised our assessment of potential flooding of the Otaki River. The areas in Otaki directly at risk of flooding are now substantially reduced.
We also work to keep people safe from flooding. This includes: advice to individual landowners on stream hazards; promoting district plan changes to regulate suitable building sites or restrictions; and general advice to the public about emergency management preparations.