Sensors for real-time flood alerts installed on Havelock North streams

The team from Adroit installing the monitors. From left, Craig Brocas, Devinda Randunu and Philippe Boulanger.

Residents living near five Havelock North streams will have a real-time view of their water levels.

Hastings-Havelock North ward councillor Malcolm Dixon described the new water flow sensors as “wonderful progress”.

“The sensors monitor the level, flow and pressure of the streams and quickly put out alerts on rising water levels, allowing people to be prepared during weather events.

“The sensors would be advantageous to everyone living in the area.”

Thirteen of 15 planned monitors are in place, with the remaining two to be installed after bridge work on Joll Rd has been completed and an appropriate location has been confirmed on the Karituwhenua Stream.

Once the project is complete, there will be three monitors on the Herehere, four on the Mangarau, three on Te Kahika, two on School, and three on the Karituwhenua streams.

Joll Rd was flooded during Cyclone Gabrielle, due to a huge surge of water flowing through the nearby Mangarau Stream.

More than 40 properties near the Mangarau Stream were placed in Category 2C after the cyclone.

Earlier this month, the property owners were informed they had been recategorised as Category 1, the lowest flood-risk category, after almost two and a half years in limbo.

In May, a report from Chief Ombudsman Peter Boshier chided Hastings District Council, saying it had not acted for years despite concern from engineering consultants Stantec, which conducted annual checks of the dams, where it noted that their failure would cause significant damage and could result in deaths.

Hastings Mayor Sandra Hazlehurst said the project was valuable for Havelock North residents, who could now be reassured that, in severe weather, timely data would show the water levels on the streams.

“The five streams all run through residential urban areas into the Karamū Stream, so we need near real-time information on what is happening.

“Council will monitor and be able to see trends over time to inform future planning and investment, and monitor stream levels during heavy rain.”

Council staff are monitoring the sensors and, from September, once a process enabling the data to be fed through to the website is complete, residents will be able to access a dashboard to view the information.

The council has partnered with Adroit Environmental Intelligence to install the real-time environmental monitoring sensors.

Council programme manager Darren de Klerk said the website dashboard would integrate water-level data with MetService information and the Havelock North dam monitoring system, to provide a unified view for the council to monitor and residents to check.

“We are excited about releasing this dashboard on our website. It will help build confidence within the community, with residents and other interested people able to keep an eye on stream levels,” de Klerk said.

Adroit general manager Guy Macpherson said the monitoring system was the most comprehensive example of environmental sensors used for flood detection and emergency response in New Zealand, and was “likely to set the standard for other councils and regions”.

LDR is local body journalism co-funded by RNZ and NZ On Air.