A potential flood risk still exists in coastal Otago as persistent heavy rain continues to affect the area from the Taieri Plain to the Waitaki River.
ORC rainfall sites in this area have recorded between 15 and 60 mm between midnight and 3pm today, with the heaviest totals recorded in the headwaters of the Leith and Silver Stream catchments in Dunedin. Typical rainfall rates have been relatively modest at 2-4mm per hour, although heavier intensities of 6-8mm per hour have been observed at Swampy Summit, and at Pine Hill.
MetService predicts that rainfall will begin to ease overnight, although showers may persist in some areas well into Wednesday.
On the Taieri Plain, the Silver Stream is responding to the persistent rainfall, increasing to 80 cumecs at 3:30pm. This is about 80 cumecs below the level at which it begins to spill over the Gordon Road Spillway, opposite Mosgiel. The Silver Stream was continuing to rise at 5-10 cumecs per hour this afternoon, and council staff will continue to monitor this closely overnight.
The Taieri River at Outram was steady at just under 200 cumecs at 3:30pm, and is expected to peak at about 300 cumecs tonight.
In Dunedin, the Water of Leith remained steady at approximately 35 cumecs by mid-afternoon today. The first flood warning level for the Leith is 55 cumecs, and there is potential for break-out from the main channel when flow exceeds around 100 cumecs.
Rivers in North Otago are also beginning to respond to the heavy rainfall over the last few days. The Shag River was at 62 cumecs at 3pm, above its first flood alarm of 30 cumecs. The Kakanui River at Clifton Falls was also rising rapidly, and was at 85 cumecs at 3:30pm, approaching the first flood warning level of 100 cumecs. It is expected that the Shag, Kakanui, and Waianakarua Rivers will continue to rise into the evening, and will peak overnight.
ORC duty flood manager Mike Goldsmith said the council is continuing to advise those living in low-lying areas to keep a close watch on river flows and surface flooding.
“As the ground has been heavily saturated from the sustained rainfall over the past few days, river flows can change quite quickly, and everyone needs to be vigilant and keep a close eye on river levels” Mr Goldsmith said.
River level and rainfall information can be checked on the ORC water info webpage
www.orc.govt.nz/waterinfo or by phoning 0800 426 463