Heavy rains changes Kowhai River courses and washes away edge of Amberley Domain
Heavy rain in North Canterbury earlier this week caused a section of the Amberly Domain to wash away.
Coming off three years of drought conditions, North Canterbury is having its wettest year in decades and the deluge earlier this week caused another round of surface flooding and river levels to rise.
Environment Canterbury (ECan) rainfall data showed intense rainfall at the White Gorge station, in the upper reaches of the Kowhai and Waipara rivers, with 133 millimetres falling between Saturday and Wednesday – peaking with 57mm on Sunday night.
The intense downpour dramatically increased the flows of the two rivers, so much so that the Kowai River rose to a point, peaking at 1am Monday morning, that it changed course near Amberley and swept away the bank bordering the Amberley Domain.
About 850 square metres of the bank was eroded between late Sunday night and Tuesday, destroying a section of walking track.
Further north, the Clarence Bridge was closed due to flood damage after the road approach to the bridge was washed out. The damage has been assessed and repairs to the bridge and approach are planned to be completed by mid-November.
While unable to control the rivers, the Hurunui District Council (HDC) and its maintenance contractor Sicon placed a high emphasis on improving the ability of the existing infrastructure to cope with the deluge of rain following the extended drought.
HDC roading team leader Kushla Tapper said an additional crew had been established to keep culverts and bridges clear, and deal with small slips.
"The grader operators have been steadily widening the gravel roads, re-establishing lost water channels and putting more shape back into the road, allowing water to run down the edges rather than wash out the entire road," she said.
HDC service delivery and amenities team leader Alex Makogon has worked with private landowners and council staff to have outfall drains cleared, so rain can get away faster.
The Waimakariri District Council reported no major incidents aside from several road closures due to surface flooding and fords closed due to water flows.
Following a wet 10 months, forecasters predict warmer, drier summer conditions for the rest of the year.
Since MetService began recording rainfall in 1943, the data shows 2017 to be the fifth wettest year for some parts of Canterbury.
The MetService weather station in Culverden recorded 362mms from January to September in 2016, with an annual total of 459mm.
From January to September this year, it had already recorded 453mm before the wet start to October.