Not slipping away: recovery efforts after July’s rain

It’s great to see the sun shining again (most days!), though many farmers in the Ōhiwa catchment are still dealing with the aftermath of the intense rainfall event that hit the Waiōtahe Valley and Ōhiwa catchments on 30 July. Despite the significant damage across a relatively localised area, the event didn’t make national headlines. However, it certainly occupied many local minds then and now.

Rainfall data from the Regional Council’s gauge at Whakatāne River (Awahou) recorded 225mm - a 1-in-56-year event. With 197mm recorded the Nukuhou North rain gauge was not far behind. Helicopter footage captured the scale of flooding, and numerous slips were observed, particularly on northeast-facing slopes, similar to those seen during Cyclone Gabrielle in Tairāwhiti.

Large hillside slip near the Hurike inlet, eastern Ōhiwa Harbour, July 2025. Image: BOPRC

One particularly affected site was a steep gully head on private land where the Hurike Care Group had planted over 2,000 plants in recent years. Unfortunately, the latest event triggered a major slip, mobilising over 2,500m³ of sediment and resulting in the loss of many of those plants. Farmer Ken Barsdell who happened to be at the scene with his mokopuna Tama when the slip came down is grateful no one got harmed and that damage to his shed and ute was relatively minor. For the recovery of the hillside, he can count on the help of his neighbours, especially the members of the Hurike Care Group. It is not coincidental that the group took its name from a war party that turned to make a stand at the head of the inlet. The name was chosen as their goal of turning to face the challenges of the modified environment here and make a stand through conservation work.

Remedial efforts are now underway, including planting shrub willows to stabilise the slope, grass seeding exposed soil, and redirecting water flow away from the toe of the slip to reduce further sediment movement.

In a timely fashion, on 9 September, the Waiōtahe Water Care and Ōhiwa/Nukuhou Catchment Groups hosted an event focused on best-practice hill country management to help mitigate the impacts of weather events such as the 29 July rain. The event featured speakers from Te Uru Rākau, Bay of Plenty Regional Council, Beef + Lamb NZ, Federated Farmers, DairyNZ, and others. Topics covered included erosion and sediment control in hill country, native revegetation, the use of poplars and willows, regulatory frameworks, and farm management strategies to reduce erosion risk. The event drew over 40 attendees and was well received, with particular interest in the Emissions Trading Scheme. The Watercare Group is now considering a smaller, on-farm follow-up session.

During the spring recovery phase, the Bay of Plenty Regional Council supported the planting of 1,250 poplars, 2,500 shrub willows, and 17,500 native plants across the catchments, with additional planting efforts underway through private initiatives. Earthworks contractors were kept busy for months, clearing debris from tracks and fencelines.

The bigger picture. Extensive damage on north-east facing slopes, July 2025. Image: BOPRC

It is also worth noting that river bed control structures installed by the Bay of Plenty Regional Council on the Nukuhou River in a trial earlier this year performed as expected. The winter floods provided a significant test, with three rainfall events exceeding 30 m³/s over a four-week period in July, culminating in the Waiōtahe–Ōhiwa flood on the 30th. To address ongoing bed degradation and associated bank erosion across the catchment, the Bay of Plenty Regional Council has applied for consent to construct additional bed control structures in the Nukuhou River and its tributaries. These works are scheduled to commence in the new year.

More information

For more information on the Ōhiwa/Nukuhou Catchment Group contact Frances van Alphen, Catchment Group Support, NZ Landcare Trust, Phone 027 944 4238 Email: frances.vanalphen@landcare.org.nz