Heavy rain is continuing to fall on the Otago headwaters today, after easing yesterday evening. A current MetService
severe weather warning is in place until 4pm today.
River flows feeding into Lakes Wanaka and Wakatipu, such as the Dart River and Matukituki are beginning to increase
further after flows dropped briefly last night.
There is also a strong wind watch in place for the region, excluding Clutha district, which can exacerbate the effects
of high lake levels.
With the current rainfall forecast and the rising river flows on Otago’s headwaters, lake levels will continue to rise
today and in the coming days.
Both Lake Wanaka and Lake Wakatipu are currently above the high lake level threshold.
Wakatipu
Lake Wakatipu is currently at 311.05m, which is close to the level where water from the lake can enter low lying
lakeside reserves and potentially the stormwater system in Queenstown. The lake begins to overtop into lower lying parts
of the Glenorchy Waterfront Reserve at a level of 311m.
This lake level for Wakatipu is still well short of historic flood levels such as the November 1999 event (312.8m) and
May 2010 event (311.48m).
Wanaka
Lake Wanaka is currently at 279.73m. Updated modelling by ORC’s flood management team shows that the lowest-lying parts
of Ardmore St are likely to see some flooding from the lake this week.
This level is above the January 2013 peak (279.4m), but well short of the November 1999 peak (281.3m).
However, lake levels and river flows will continue to be high for some weeks, meaning there is a continued risk of
further flooding.
Downstream
Elevated river flows are beginning to move downstream through the Clutha / Mata-Au River catchment. There are currently
no concerns about ORC’s flood protection schemes in Alexandra and Balclutha handling the expected flows downstream.
People operating 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.
The focus of ORC’s monitoring is extending throughout the full catchment as water moves downstream. The sequence of rain
events and duration of high water and flow levels will continue to pose a risk throughout the catchment.
Rainfall
MetService have indicated that further periods of heavy rain are expected for the rest of the week. MetService forecasts
that rainfall amounts will exceed warning criteria with confidence on Friday and moderate confidence on Saturday.
Outside of the headwaters of the Clutha / Mata-Au River catchment, there is no significant rainfall predicted for the
rest of Otago, and high flows in rivers elsewhere in the region are not expected.
For the latest info on river flows and lake levels, visit: www.orc.govt.nz/managing-our-environment/water/water-monitoring-and-alerts
Twitter: @ORCfloodinfo
MetService: www.metservice.com
Otago Civil Defence and Emergency Management: https://www.otagocdem.govt.nz/