Update - 13 February 2018 10:00 am
The latest information from the Bay of Plenty Regional Council floodroom confirms that there was less rainfall than predicted yesterday and overnight, which reduced the river flows anticipated in the Rangitāiki River.
The flow entering the Matahina Dam peaked at around 300 cubic metres per second, and in the lower river the flow at Te Teko peaked at around 250 cubic metres per second at 7pm last night. That downstream flow reflected the normal practice of lowering the level of Lake Matahina to provide buffering storage which can then be used to take the top off the expected flood flow. The Lake is now refilling, but is still well below the normal minimum operating level.
Currently, the lower river is flowing at around 170 cubic metres per second, which in terms of the river’s flood protection infrastructure is very comfortable.
Attention is now switching to Cyclone Gita, which MetService modelling indicates is likely to track down into the Tasman Sea, potentially reaching New Zealand early next week. That situation will be monitored, and precautionary actions will be taken as required once the likely weather patterns become clearer.
The Rangitāiki River is expected to reach a peak flow of 330 cubic metres per second at Te Teko overnight (Monday/Tuesday). That flow is well below the level which would cause any concerns about stopbank integrity, but the situation is being closely watched by the Bay of Plenty Regional Council floodroom, with live telemetry on rainfall and river flows being continuously monitored.
In preparation for the predicted flood flows in the river, Trustpower’s Matahina Dam is being lowered to 71.6 metres to provide buffering storage, which will be used to ‘take the top off’ the flow reaching the lower Rangitāiki River.
Whakatāne District Council Civil Defence staff are also in regular contact with the Regional Council floodroom and are monitoring the situation reports provided. In the unlikely event that there is any significant change in the situation, information will be immediately posted on the Council’s social media platforms and shared on the Kia Kaha Facebook page. A further update will be posted by mid-morning tomorrow (Tuesday).