River inspections by Bay of Plenty Regional Council staff are continuing throughout the night and most rivers have peaked and waters are receding. There continue to be a number of at risk areas, particularly on the Rangitāiki River.
Tonight, staff continue to monitor the situation with stopbank inspections and forecasting work.
The rainfall from ex-cyclone Debbie has led to unprecedented river levels throughout the Bay of Plenty, with some flows reaching more than 30% above the one-in-100 year flood event for which most stopbanks in the schemes are designed.
Most rivers have now returned to below warning levels. The Kaituna remains high but not of concern. The Whakatāne River also peaked at high tide (around 2:30pm) with just 300mm below the top of the banks in some areas. Flows are still high but slowly receding.
The Rangitāiki River remains the main focus for the team. We have put rock armouring and toe loading in several at-risk areas and we will be able to see the effectiveness of this action at first light. We know there are a few areas of seepage that we are keeping an eye on and hope that as waters recede overnight these will ease.
Floodwaters continue to come through the breach on College Road at Edgecumbe but as waters lower, we’ll be able to better assess the breach and we may be able to fill the gap as a temporary measure on the weekend.
By using storage capacity in Matahina Lake, we were able to reduce the peak flow down the river by about 110 cumecs (about 12% of the peak flood flow). The dam has been spilling at 700 cumecs but we have been able to reduce this by 50 cumecs to 650 cumecs as river levels upstream of Matahina dam decrease. This would be felt downstream after midnight.