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Hapuku bridge dam-breach detection system installed

New equipment to provide early warning to drivers on SH 1

The NZ Transport Agency has installed dam-monitoring equipment upstream of the State Highway 1 bridge at Hapuku, north of Kaikoura. 

Together with warning lights and signage on the approaches to the bridge, the equipment is designed to alert motorists immediately in the event of a dam-burst upstream.

A similar alert system has also been installed on the Ote Makura bridge on State Highway 1 in Goose Bay, on the south side of Kaikoura.

'The aim of this equipment is to provide an immediate alert to road users and anyone in the riverbed area at that point in the event of a dam-burst,' says Pete Connors, Regional Performance Manager for the Transport Agency.

The dam monitoring equipment registers any change to the level of the water upstream of the bridge, which activates the flashing light system.

'There is a 150 metre high dam upstream of the state highway bridge at Hapuku formed by an earthquake-generated slip, and this warning system will help to ensure the safety of Kaikoura residents, road crews and others working on the state highway north of the town,' says Mr Connors.

Image from the web monitoring site showing the signs at the Hapuku Bridge:

'The system is designed to warn people quickly so that they can get well away from the river and bridge in the event of a dam burst upstream. If the lights are flashing the message is to get well back from the bridges’ approaches as well as off of the bridges themselves.

'If there is a flash flood, there may be delays between when the lights activate and the water actually reaching the bridges, so people need to bear this in mind and heed the warnings,' says Mr Connors.

'We know that a number of other streams along the Kaikoura Coast also have slip dams behind them. We want everyone in or around rivers and bridges in Kaikoura to be on the lookout for changes in water colour. A sudden change to cloudy or dirty water or floating debris should be an alert to get away from the riverbeds or bridges.'

Background story from Fairfax journalists about the dam on the Hapuku:

http://www.stuff.co.nz/national/nz-earthquake/86567707/resident-witnesses-rock-fall-which-created-dam-at-risk-of-bursting(external link)

(external link)For more information on the dam risk north of Waiau:

https://ecan.govt.nz/landslide(external link)

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