Hastings River Sensors Pass Their First Big Weather Challenge

The system, which uses Adroit-supplied VEGA radar river-level sensors installed at key points along five Havelock North streams, operated continuously as the storm delivered heavy rainfall to large parts of the North Island.

While Hastings was spared the extreme impacts experienced elsewhere, the event provided the first opportunity to see how the river monitoring system performed under sustained rainfall and elevated flow conditions.

Monitoring capability developed after Cyclone Gabrielle

Hastings District Council’s investment in live stream monitoring followed Cyclone Gabrielle, which struck Hawke’s Bay in February 2023, delivering three to five times the normal monthly rainfall in just 48 hours. The cyclone exposed the limitations of manual observation, fragmented data and delayed visibility during such extreme weather events.

In response, Council implemented a real-time river monitoring network across five streams flowing from Te Mata Peak. The network uses non-contact radar sensors mounted at strategic locations, including upstream, mid-catchment and downstream points. These sensors measure river height continuously and transmit data through the connected information network into a live dashboard.

The dashboard brings river-level data together with rainfall information and dam status, providing a consolidated, catchment-wide view of how water is moving through the system during rainfall.

Monitoring the January storm

During the January weather event, the sensors captured continuous, near-real-time data as rainfall accumulated across the catchment and stream levels lifted in response.

Rainfall totals exceeded 100mm in a 24-hour period, with periods of higher intensity rainfall overnight. River levels rose progressively across all monitored streams, tracking as anticipated and remaining below alarm thresholds throughout the event.

Council’s Director of Infrastructure and Deputy Group Manager Darren de Klerk says the system delivered exactly what it was designed to provide.

“It gave us much greater visibility on how the network was performing,” de Klerk said. “It allowed us to clearly see how the streams were responding as rainfall continued, and how the system behaved as conditions changed.”

Real-time information for operational decision-making

Throughout the event, live river-level data fed directly into Council’s monitoring dashboard. The platform was shared internally with infrastructure teams, emergency management staff and contractors, with the data publicly accessible on Council’s website dashboard.

The data confirmed that river levels were behaving as expected, informed inspection timing, reduced unnecessary field deployment, and ensured stakeholders were working from current, measured information.
Importantly, the system also provided confidence to residents. While rainfall was significant and conditions elsewhere were deteriorating, the data confirmed that levels in the Karanema, Herehere, Mangarau, Te Kahika, and Karituwhenua streams were not approaching critical thresholds.

Adroit General Manager Guy Macpherson said it was great to be part of the Hastings installation and to see the system in action during its first major weather test. “It was fascinating to watch the live data showing how rainfall and stream levels interacted across the catchment.

“As a stakeholder, it was reassuring to see the sensors and installations performing exactly as designed throughout the event,” Macpherson said.

De Klerk noted that the value of the system extends beyond emergency response. “It gives us a better understanding of how the network behaves,” he said. “That information is important not just during storms, but for future planning and investment decisions as well.”

While sensors do not replace physical inspections, the ability to correlate measured river levels with on-the-ground observations improved situational awareness and reduced uncertainty during the event.