They are predicting between 80-120mm of rain to fall over the 30 hours from midday Monday to Tuesday (overnight) for Coastal Otago. ORC has identified possible risk areas based on the current Metservice forecast issued today.

“While most Coastal Otago rivers have capacity and are at flows which can sustain heavy rain, and despite amounts of rain not yet fully known, we’re taking a cautious approach to tell people what our modelling says based on the information so far,” says ORC Duty Flood Officer Sam Yeo. 

ORC flood forecasting shows areas to focus on based on the current rainfall forecast are the Silver Stream catchment including the Gordon Road spillway near Mosgiel, and the Riverside Rd spillway downstream of Outram.

“This is an early heads up that while we hope no overtopping will occur, people should still prepare and remain watchful and mindful that surface flooding and localised overtopping could occur particularly overnight Monday and into Tuesday morning.

“We have staff rostered and ready and will be closely monitoring the situation and any change anywhere along the coast over the next 48 hours.”

Other areas under close watch include, but are not limited to, the Water of Leith and the Lindsay Creek catchments. Also, the Pomahaka River in South Otago, and rivers in North Otago.

The Council is monitoring coastal river mouths and will assess opening of river mouths on Monday.

“All these areas are within the area Metservice has today (Sunday) advised are most likely to be impacted. From past experience, these rivers can rise quickly, so we urge people to likewise exercise caution and keep an eye on all information available,” she said.

It will also pay to keep a close eye on the Civil Defence website at https://www.otagocdem.govt.nz/.

Communities can find more about river levels and flood alerts at https://envdata.orc.govt.nz/AQWebPortal/Data/Dashboard/211.

There will be a further update tomorrow afternoon (Monday 29 July) once more information and refreshed forecasts are to hand.