Caution advised as weather system looms

ORC is cautioning people in the Queenstown Lakes townships and rural areas to stay up to date with the likelihood of rising river and lake levels in coming days – with some flooding now predicted.

MetService have issued a heavy rain warning for the Otago headwaters – between 140mm to 200mm of rain - from 1am Thursday through to about noon Thursday, in addition to a strong Northwest wind warning which affects most of Otago.

ORC’s General Manager Science and Resilience Tom Dyer says people can access ORC’s environmental data portal for real-time monitoring of rivers and lakes.

"There is a strong potential for high lake levels this week, as further periods of significant heavy rain follow the heavy rainfall experienced in the last few days”.

“We’re actively monitoring lakes and rivers in the Queenstown Lakes area from now and throughout the long weekend and are advising people of the likelihood of flooding in some areas.”

Extensive flooding is expected in parts of Glenorchy.

Mr Dyer says "It’s likely there could be extensive flooding of the Northwest part of the township similar to what occurred in February 2020”.

Estimated flood extent in Glenorchy during the February 2020 flood event 

Aerial image, 4 February 2020 (Credit: Luke Hunter, Donerite Contracting).

The 2020 event (pictured) could be repeated in coming days some flooding is also expected in low-lying Queenstown streets in the vicinity of Lake Wakatipu; such as low-lying sections of Beach St, Rees St, Marine Parade, Church St and Earl St where a depth of approximately 300-400mm is likely, low lying areas of Kingston; low-lying sections of Cornwall St where a depth of approximately 200-300mm is likely, and across the foreshores of Wanaka.

Strong winds are also forecast, which may cause waves and floating debris to impact the shoreline or water levels. The strong Northwest winds are expected later turn Southwest, the latter predominantly affecting the Clutha district.

Landsliding or debris flows triggered by high rainfall totals or intensities may occur on steep slopes, depending on the intensities, totals and location of rainfall and thunderstorm activity, in particular in the Makarora area (e.g. Pipson Creek, Muddy Creek), and at catchments on the Queenstown-Glenorchy Road.

Downstream in the Clutha catchment, it is expected that the Clutha River flow at Balclutha will remain elevated; but at less than 2000 cumecs for the rest of the week. There are no concerns about ORC’s flood protection schemes in Alexandra and Balclutha handling the expected flows downstream.

People in the vicinity of the river need to be aware of the possibility for the flow to rapidly increase because of high rainfall in the headwaters, regardless of the local weather.

ORC is closely monitoring the river flows and lake levels and working with Queenstown Lakes District Council and Emergency Management Otago to ensure businesses in low-lying areas are aware and prepared.

Link to ORC’s Environmental Data Portal: www.orc.govt.nz/edportal 
Direct link to data portal lake levels: Www.orc.govt.nz/lakelevels 
Link to Queenstown Lakes District Council: https://www.qldc.govt.nz/october-weather-event/