Ōtara stopbank upgrade

The Ōtara stopbank upgrade will improve flood defences (stopbanks and floodwalls) along the left bank of the Ōtara River, from Ford Street to Princess Street in Ōpōtiki.

Why are we doing this?

Flooding is the most common natural hazard in Aotearoa, with a major flood event occurring on average every eight months. As the climate changes, communities across New Zealand need to adapt to meet the challenges of a rising sea level and more frequent, more significant rain events that may cause flooding.

Regular asset performance reviews of our flood defences help to ensure they are in good condition so they can perform when we need them most. A recent review of this section of the Ōtara River identified the need to upgrade these defences.

This project is one of the many we have underway across the rohe to manage, maintain and improve our flood protection network (worth more than $400m).

What’s happening?

Work to upgrade flood defences along the Ōtara River is progressing well.

Key features of the work include:

Upgrade of flood defences.
In most places, we will be raising the stopbanks between 500-700mm in height to meet the agreed level of service. We will also be upgrading and extending the floodwall further along Richard Street.
Replacement of seven culverts.
Culverts are a vital part of the flood protection network as they allow stormwater from the landside to flow out into the river. The culverts will be fitted out with flap gates to help control the flow of water. During a flood event or when the river is high, the flap gates close preventing water from the river to flow inland.

Temporary pause in construction: August – November 2026

Since construction began earlier this year good progress has been made, including completing the first of seven new culverts and starting work on the stopbank improvements.

Over winter, however, the weather made it increasingly difficult to continue the earthworks safely and efficiently.

While there were some sunny days, it was the condition of the ground - not simply the weather overhead - that became the deciding factor to temporarily pause the work until November.

Much of the project involves moving, placing and compacting large volumes of engineered fill to strengthen and raise the stopbanks and backfill culverts. This material is sourced both on site and from a local quarry and, following prolonged wet weather, it remained saturated.

For the fill to achieve the required strength and stability, it needs to be placed and compacted at the right moisture content. The combination of wet conditions and low ground temperatures meant the material was not able to dry sufficiently to meet the required standard.

The wet ground also made it increasingly difficult for heavy machinery, including large excavators and trucks, to operate safely and efficiently across the site.

Pausing the main earthworks will allow ground conditions to improve and temperatures are warm enough for the fill material to dry and achieve the required performance.

The existing detour around the Ōtara River stopbank work site will remain in place while construction is paused. This is because some areas within the work site remain exposed and need to be kept secure while the project is temporarily on hold. The detour will also remain in place when construction recommences, until all work is complete and the area is safe to reopen.

We appreciate the inconvenience this may cause and continue to be grateful for your understanding.

The project is currently programmed for completion before 30 June 2027.