High flows in the lower Waitaki River are expected to continue "for days, if not a week" as Meridian Energy copes with more than 550mm of rain which has fallen in the Mt Cook area of the Southern Alps in the past five days.
Meridian is managing to keep the river below 1500cumecs, the trigger point at which the twin bridges on SH82 at Kurow were closed between 6am on Sunday and 7am yesterday.
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The New Zealand Transport Agency kept the bridges open last night, with the river flowing at 1423cumecs at 5pm, not reaching the 1800 to 2000cumecs Meridian had feared.
The agency's South Canterbury area manager, Colin Hey, said the bridges were inspected yesterday and had not suffered any damage.
They would continue to be inspected daily while the high flows continued.
Meridian had indicated it expected to keep the flow below 1500cumecs, which meant the bridges could remain open at night.
Meridian spokeswoman Claire Shaw said yesterday that while the heavy rain event was over - yesterday until 5pm Mt Cook got 38.5mm of rain - the big inflows into the Pukaki and Tekapo storage lakes were continuing.
While rain had eased, a lot of water still had to flow into the lakes, and then be spilled through Meridian's Waitaki system.
Lakes Tekapo, Pukaki and Ohau remained overfull yesterday, although Miss Shaw said an accurate warning of the heavy rainfall meant Meridian had been able to plan ahead to cope with the build-up, spilling water early.
Yesterday, other rivers in the catchment were falling dramatically.
The Omarama Stream, which caused flooding in the township early on Sunday morning, reached 55cumecs and had fallen to 14.5cumecs late yesterday.
The Ahuriri River peaked at 351cumecs on Sunday and had fallen to about 90cumecs yesterday.
In Omarama floodwaters from early Sunday had receded.
The only sign yesterday of high water marks was autumn debris strewn along SH8 and lying scattered about through the holiday park.
However, the swollen Omarama Stream, which reached a 40-year peak, cut the northern approach to the bridge on the town's boundary.
That access severance closed the highway for about five hours from 9.20am, with a detour available for light traffic over a neighbouring farm using a single-lane wooden bridge.
Omarama Hot Tubs was back in operation after its parking area was flooded.
The Ahuriri Community Board and Omarama businessman Craig Dawson said the town escaped relatively unscathed from the weekend deluge.
The water supply from the Omarama Stream was slightly discoloured and the sewage ponds near the stream were now clear of floodwaters.
The only other threat to highways was at the Otamatapaio River bridge, at Lake Benmore on SH83.
The river had burst its banks upstream from the bridge, hitting the approach and cutting the bank away almost to the edge of the seal.
At that point, the road was reduced to a single lane while rocks were brought in to shore up the eastern approach.
On the lower Waitaki Plains, floodwaters from the Waitaki River were close to some houses in the Waitaki Bridge camp, but had not reached any.
Environment Canterbury was warning farmers and residents to keep a close watch on the river, which is likely to remain high for some days, for any flooding or overtopping of protection works.
