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Surveyor Norbert Schoffa carries out one of the waterway cross-section surveys currently underway throughout Northland.

Regional Council Wades into River Survey

Northland Regional Council contractors have caused some curious onlookers to wonder what is happening in the region’s most flood-prone rivers and streams.

The Council currently has three contractors surveying the Hātea, Raumanga, Waiarohia, Otaika, Ruakaka, Waitangi and Kawakawa rivers as part of the ‘Priority Rivers Flood Risk Reduction Project’, which has seen ongoing work on 27 Northland catchments identified as priorities for flood risk planning.

The survey will see 254 river cross sections, and 86 structures such as bridges and large culverts, measured in detail.

Council Rivers Programme Manager, Joseph Camuso, says the waterway cross-section survey will complement the LiDAR survey carried out by air earlier this year.

“The information gathered will add another layer of detail to computer models that will be developed and used to assess the flood risk posed by these rivers,” he says.

Mr Camuso says the LiDAR survey – a process similar to radar but using light to survey and map large areas – gathers a large amount of data quickly. However it does not see what is going on below the water level or penetrate thick vegetation.

“The Council will use the river survey information to develop more detailed computer modelling of flooding in the priority catchments, right down to the likely depths and speed of floodwaters.”

Survey work on the Awanui and Kaihū rivers is also scheduled to happen over the coming months as the next phase of flood risk plans in these catchments continues.

“The Awanui, Kaihū, and Kaeo Rivers are a year or two ahead of the others in the priority project with flood models completed and draft management plans being prepared,” says Mr Camuso.

“Ground and river work has already been carried out in these catchments so the surveys will provide updated information on the impact and where we go from here,” he says.

The initial river surveys are due for completion at the end of the month (subs: Nov) and Mr Camuso says the community will be informed of developments as the project progresses.

ENDS

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