Flooding, foothill rivers, update South Canterbury 8.30am, Wednesday May 26
The Temuka River north of Timaru has now dropped from a high of 564 cumecs (cubic metres of water per second) in the early hours of this morning. “At its highest point the three feeder tributaries - Te Moana, Waihi and Kakahu Rivers - arrived at their confluences with the Temuka at roughly similar times,” said Environment Canterbury Flood Controller Tony Henderson. “This helped maintain high flows for several hours and coincided with the high tide at the coast which effectively reduced the flow to sea.”
However by 8.30 am today it was recording 516 cumecs and both bridges, the Manse and Temuka, were safe, Mr Henderson said. Some flooding of farm land occurred on the south side of the river, however the town side of Temuka was not affected by the high river level.
The Waihao River also caused some concern overnight, Mr Henderson said, as it peaked at 772 cumecs. The river protection works have a design capacity of 800 cumecs. The river has now dropped to 671 cumecs at 8.30 am.
Environment Canterbury’s recorder at Pareora huts peaked at 389 cumecs but at 8.30 am was down to 240 cumecs. The Opihi River at State Highway 1 peaked at 655 cumecs and at 8.30 am was down to 631 cumecs.
In the last 48 hours, 120 -200 mm of rain has fallen in South Canterbury foothills up until 5.00 am today. Rain has fallen consistently throughout the night giving rise to surface flooding and rising river levels. “Any additional heavy rain may again lift river levels,” Mr Henderson said.
A further 100-140 mm of rain is forecast up until late Wednesday for the South Canterbury foothills south of the Rangitata River to North Otago. Rainfall intensities are forecast to be in the 6-10 mm/hour range with bursts of 10-15 mm/hour possible through this period.
“The overnight easterly swell delayed some drainage to the sea from rivers,” said Mr Henderson. “Once the tide turned around 1 am, this effect abated quickly.” Timaru high tide is at 1.58 pm, Wednesday afternoon.
The Canterbury Civil Defence Emergency Management Group advises people to drive to the conditions and reduce speed. Drivers should also avoid flood waters.
For more information about preparing for emergencies, go to www.getthru.govt.nz
For information regarding road closures, go to:
http://www.nzta.govt.nz/traffic/current-conditions/highway-info/road/8373/south-island.html
For more about the latest river flows call the Environment Canterbury 24 Hour River Report Info Line 0900 RIVER (74837). Charges do apply.
Temuka River at Manse Bridge recorder web page:
http://ecan.govt.nz/services/online-services/monitoring/river-flows/pages/river-flow-chart.aspx?SiteNo=69602
Waihao River at McCulloughs:
http://ecan.govt.nz/services/online-services/monitoring/river-flows/pages/river-flow-chart.aspx?SiteNo=70902
Or you can check river levels and rain recorders on:
http://ecan.govt.nz/services/online-services/monitoring/river-flows/
http://ecan.govt.nz/services/online-services/monitoring/rainfall/
Rain radar map:
http://www.metservice.com/national/maps-rain-radar/rain-radar/all-nz-rain-last-6-hrs or for general forecasts www.metservice.com