Hastings District Council Leads the Way in Flood Detection for Safer Communities

Hawke’s Bay was among the worst hit. Stopbanks failed in more than 30 places, rivers burst their banks, power and communication networks collapsed, and entire communities across the Heretaunga Plains were left isolated.

The scale of damage, more than NZ$5 billion in Hawke’s Bay alone, triggered a fundamental rethink. Across the country, councils began asking the same question: how can we better detect, respond to, and communicate flood risk? And how can the public be given the tools and information to assess and manage some of that risk to themselves, their families and communities?

And following on from that, what role could new technology play in recording and reporting actual rainfall and flood risk in real time?

In Hastings, that question led to action. Hastings District Council engaged engineering and infrastructure consultancy Beca to identify a real-time flood risk monitoring solution that would support greater resilience in the Havelock North area, where five streams converge and flow through densely populated urban areas, increasing the risk of damage during high-intensity rain events.

HDC Network Engineer, Garry Rippon and Programme Manager Darren de Klerk, met environmental monitoring specialists Adroit at the Water NZ Conference in 2024.

They tasked Beca Project Manager, Fraser Mackenzie to investigate the stream monitoring system further.

Mackenzie says it was clear Adroit had a solution that was a great fit for the Karenema Havelock North Streams — so at the beginning of this year, started a three-month trial with them.

“That trial was a success and we're now rolling out into another 13 locations, on the Havelock North streams.”

The Havelock North solution is a comprehensive example of environmental sensors to be used for flood detection and emergency response and is likely to set the standard for other New Zealand councils and regions to follow.

Mackenzie says it’s the kind of work that defines what resilience can look like at a local and individual property level.

“We needed a solution that gave us the ability to be better prepared and understand how the streams responded during different rainfall events. We also wanted to provide this information to the community.”

Darren de Klerk, now the council’s Deputy GM Infrastructure, has been working intensively with the Havelock North community since March 2023 on building a greater understanding, awareness and resilience to help prepare for future disasters.

The Adroit Solution

The Adroit monitoring solution centres around VEGA radar-based river level sensors, designed to collect real-time river-height data and upload it to the cloud and also a public website.

The VEGA sensors are to be installed in 15 locations, primarily on bridges, to detect rising water levels and potential blockages early.

For the trial, two locations were chosen: one on the Mangarau Stream and one on the Herehere Stream, both selected due to their much larger flow capacity compared to the other three main streams in the region.

Data is collected every 15 minutes by the sensor, processed via an onboard EWS EMT datalogger, and transmitted to the Adroit Cloud Platform via Spark’s CAT-M1 cellular network – although satellite connectivity via the Iridium network will be utilised in two areas with poor coverage. The EWS dataloggers are both cellular and satellite capable as required.

In normal conditions, data uploads occur hourly, but during high-risk periods, uploads will increase automatically to every 15 minutes to ensure near real-time visibility. Sensors are configured with pre-set thresholds based on local hydrological models, enabling early warnings to be issued to council teams and maintenance contractors automatically as water levels rise.

Each sensor is solar-powered, with internal diagnostics that track battery health and trigger alerts if performance drops. The system is designed to be both robust and low-maintenance, allowing for reliable year-round operation even in challenging environmental conditions.

All incoming data can be viewed on the Adroit platform dashboard, where a series of alerts are set up in the system to notify key stakeholders when certain thresholds have been reached.

And with the number and placement of the sensors, the data helps give clarity on what’s happening at the various sites, as a weather event unfolds.

“We now have the ability to say with some degree of accuracy: there's an event happening in Havelock North — that this is the current level of the stream and that you can see on this graph it’s trending upwards,” Mackenzie says.

de Klerk says: “With defined emergency protocols supporting an emergency and incident action plan, this means emergency management staff can make informed decisions”.

It is here Hastings District Council is going a step further, with data from the sensors planned to be integrated into a public website with their local weather information and existing dam monitoring systems — giving council staff, emergency managers, and the public a unified view of catchment behaviour.

Installation Considerations

Because the sensors are for measuring floods and hazardous conditions, careful site selection was based on both hydraulic modelling and maintenance practicality. Stantec, the council’s hydraulic modelling consultant, modelled ideal sensor locations for maximum flood risk coverage. Maintenance contractors then reviewed those locations to ensure they could be safely and regularly accessed.

There was some complexity in sensor placement. For example, sensors needed to be central to the river (not necessarily central to the bridge) and on the upper side of the bridge where blockages caused by slash could occur. They also needed to be accessible by maintenance contractors without requiring special equipment or planning.

“Adroit are quite clever in the way that they put the sensors on the upstream side of the bridge. By putting it on the upstream side, you actually get a better understanding of any issues within the stream, which is good because during Cyclone Gabrielle blockages were a big aspect in how the streams handled the flows,” Mr Mackenzie says.

The rollout also required collaboration with private landowners, particularly where shaded reserves couldn’t provide enough solar power for the sensors to operate all year round. Rather than being seen as an imposition, the response has been positive.

“The two landowners that I've spoken to directly both saw it as a positive contribution to the community and were quite excited to have a sensor on their property,” Mackenzie notes.

Visibility Builds Trust

For Hastings District Council, the value of the system goes beyond technology. It provides vital data to inform emergency responses and future infrastructure planning.

“One of the outcomes was to get better visibility and connectedness between how the dams were operating and then, how the streams would respond as water flows down the catchment,” de Klerk says.

“And then the other part is around helping us to help the community to get a better sense of risk and self-manage some of that. Something like 90 per cent of the impacted land the streams run through is private, so by having visibility and transparency through a website or a dashboard, the community can look at a monitor close to their property during an event, to get a feel for what the stream is doing.”

de Klerk believes public access to the platform will help build confidence within the community. “While we think we know what's happening and how the stream will respond, it's actually having the real-life data and visibility that will help residents understand the risks and what actions we’re taking.”

He adds that having a public website showing the data will be helpful not just for residents, but for council staff and even construction teams monitoring conditions on active sites. The council expects to launch the public dashboard by September, with features including top-of-bank indicators, tracking against historical events and return period overlays.

de Klerk says he’s quick to check the online dashboard himself whenever there is more than an average rain event. “Not for my own safety, but I do have rain anxiety for the community, so I am interested to see the data.”

A New Paradigm

Guy Macpherson, General Manager of Adroit, says the project demonstrates the power of applying reliable technology in a new context. The VEGA sensors and cloud platform are proven tools, but their integration into a coordinated public communication system is what makes this deployment stand out.

“This is just one of our stock standard solutions monitoring flood detection using radar,” says Macpherson. “What’s exciting here is how it’s being used — not just to monitor water levels but to pass that data on to the public.”

He says that the wide variety of Adroit environmental sensors that can be added to the system means there are many more opportunities to build on the Hastings model in future — including devices that measure slope stability, sensors to measure rising ground water and cameras for visual verification.

“In many of our installations, the VEGA radar sensors are paired with cameras, so if a threshold is reached and an alert is triggered, stakeholders can immediately check for visual verification,” Macpherson says. “Or in the case of an area known for slips, a sensor reporting ground movement could save a wasted (or risky) journey for an emergency worker or a member of the public,” he says.

For Adroit, it’s about scaling up trusted technology to meet a growing national challenge. He believes the future lies in more councils adopting similar models.

“We hope we’ll be able to utilise the full suite of tools in a project of this magnitude in the future. With the climate changing, councils want tools that are resilient, fast, and accurate,” Macpherson says. “That’s what we’re delivering.”

In the shadow of one of New Zealand’s most significant climate events, real-time environmental monitoring has proven its value as a vital component of resilient infrastructure planning. Hastings is showing how it can be done — and how the public can be kept informed, engaged, and part of the solution.