The annual drawdown of Lake Rotoiti will begin over the coming days and will see the lake drop 100mm below its normal operating range.
Bay of Plenty Regional Council lowers the lake by an extra 100mm each year as part of consent guidelines to help facilitate flushing of the Ōhau Channel and reduce flood risk in the channel.
The regional council is planning to hold at those lower levels for a few weeks if the weather allows, so that lake margins and assets like jetties and boat ramps can be checked.
The council's principal engineering surveyor Graeme O'Rourke said the council had between 36 and 55 days to achieve the drawdown each year.
"Looking at the forecasts, we hopefully have a few weeks of low rainfall which is our best opportunity to get the lake levels down and flush the channel.
"Because of the weekend's rainfall we have a few extra centimetres to get down to the main operating range and then drop into the 'drawdown zone' from there.
"That means the Okere Gates will be fully open for at least the next week or two as we work to get the annual drawdown completed as painlessly as possible."
O'Rourke said anyone with any issues or observations around Lake Rotoiti should note the details and take photos for the record before contacting the regional council.