New Zealand / Local Democracy Reporting

Radar guns won't stop speeding - but they may head off a flood of complaints

18:36 pm on 10 August 2022

New radar gun equipment is being used by West Coast Regional Council hydrology staff to gauge floodwater levels of rivers across the 650km-long region.

Regional council hydrology staff undertaking water monitoring with one of the new water radar guns. Photo: Supplied / West Coast Regional Council

The 15 new Waterwatch radar sensors or 'guns' costing $1500 are being used to fill gaps in the council's current flood observation network across the region.

Planning and science manager Rachel Vaughan said the new sensors were basically hand-held radar guns although they could also be more permanently attached to bridges or other existing river monitoring structures.

An advantage of the new equipment was the guns did not need close contact with what they were designed to measure.

"They don't actually endanger our staff - they are above the water, not in the water," Vaughan said.

The guns had the capacity to measure the water surface relative to the level of aggradation of the riverbed, could be calibrated to compare different events, and were less susceptible to damage.

"It's a great, relatively low-cost system to be able to roll out across the region."

The hydrology report to the council meeting yesterday noted a busy July for staff with site maintenance and improvements under way.

Flood level monitoring by radar gun on the Waiho River Bridge at Franz Josef by West Coast Regional Council Staff. Photo: Supplied / West Coast Regional Council

A new water level sensor had been installed at Waipuna on the Grey River to improve the quality of the data collected, while the Hokitika River at the Kaniere Bridge had been measured at its highest level since the new radar gun at that site was installed in January.

Council staff had also assisted with flood observations at the Waiho (Waiau) River.

Planning was under way to install a satellite to boost communication at the Mokihinui River site in northern Buller, and staff had been building bridge brackets to attach the 15 new Waterwatch radar sensors.