Culvert 49 repairs - Kauarapaoa Road

• Completion Date17 October 2025

The Culvert 49 repair project on Kauarapaoa Road addresses ongoing damage caused by high water levels and debris washing down the Mangaiti Stream.

In December 2021, the culvert was damaged, followed by further damage to the temporary culvert in February 2022, when slash blocked the culvert and caused water to overtop the road, scouring the surface and damaging existing infrastructure. Currently, two strengthened shipping containers are in place as a temporary crossing, but they are at risk of being blocked by debris in future storms.

To provide a long-term solution, the existing culvert will be replaced with a 32.8-meter box culvert, 3.0 meters wide and 3.5 meters deep, allowing the Mangaiti Stream to flow into the Kauarapaoa Stream and exit into the Whanganui River.

The new design will include a debris rack upstream to catch slash and is capable of allowing water to flow over the road during extreme weather events. This will increase the resilience of the river crossing and reduce the risk of further damage from scour and debris.

While the road remains open with the temporary crossing in place, the new culvert will restore the road to its original alignment. Work on the project began in December 2024, with completion expected in the last quarter of 2025.

Image: Repairs to Culvert 49 in 2022