Narrows Bridge erosion investigated


Tamahere’s Narrows Bridge has been been reduced to one lane until further notice as concerns mount over Waikato riverbank erosion.

And nearby residents say those concerns are very well founded, with 15-20 metres of riverbank on the northwestern side of the Waikato River having been lost over the past five years, reports the Waikato Times.

The bridge, which crosses the Waikato River just south of Hamilton at Tamahere on State Highway 21, has been operating with one lane since August 31 after the New Zealand Transport Agency sought to reduce its load while investigations are undertaken to assess the potential impact of riverbank erosion damage.

State highway manager Kaye Clark said recent national analysis raised agency concerns.

“The bank erosion has been taking place over many years but has reached a point where more in-depth investigations are now warranted,” she said. Lane reduction was “a precautionary measure” to protect the bridge from potential damage until damage and repair work had been assessed. Steep banks will make any repair work challenging.

Residents said erosion had emerged as a real problem since renewed consents granted in 2006 allowed Mighty River Power – which operates the Waikato hydro system – to increase river flows. Waikato district Tamahere councillor Wally Hayes, who lives 400 metres from the bridge, has aired concerns at his council’s past two annual plan hearings.

“It has been brought to attention in council chambers, but everyone has conveniently ignored me,” he said.

Mark Topping, whose property borders the river, said a walkable path 10-15 metres wide along the riverbank had slowly disappeared.

“That’s all gone since the change of consents,” he said. “You can’t walk along it any more.

“There has been a hell of a lot of erosion through the whole Narrows area over the past five years or so.

“The council and community have lost an asset since the river flows have been increased.”

Meanwhile the one-lane operation on Narrows Bridge is now controlled by traffic lights, with motorists travelling to Hamilton International Airport warned to allow extra time for trips.

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