The unusually dry winter has forced the Whakatāne District Council to undertake sand-disking operations at the Whakatāne River bar, starting next week.
Disking will be undertaken at the peak of the outgoing tidal flow and aims to loosen the compacted sand between the “Narrows” at the river entrance and the river bar, about 50 metres offshore. The loose sand will be taken out to sea in the tidal current, to a point where a proportion of it will carried away by the west-east current along the coast.
“Whakatāne Coastguard and a number of commercial and recreational users have indicated that the water depth between the Narrows and the bar has reduced to a point where safety is being compromised,” says Julian Reweti, the Council’s Community and Economic Development General Manager. “At low tide, with the river’s current flow, the water depth is just 400 mm. We have a restriction in place now which means the river entrance can’t be used three hours either side of low tide and if the situation doesn’t improve, that restriction may need to be extended to four hours.”
He says the ultimate goal of the disking operation is to increase the depth at the entrance at low tide to 1.5 metres – the point where access restrictions come into effect. “That could take a number of weeks to achieve, depending on river flows and whether or not we have any significant heavy rain events to help flush the sand at the entrance away.”
With the annual whitebait season having just started, concern about potential effects on whitebaiting activities has seen the Council restrict the disking operation to weekdays, targeting the peak flow period of outgoing tides when the number of whitebait entering the river will be at an absolute minimum.
“We’ll monitor the situation closely and adjust the disking operation to suit,” Mr Reweti says. “Clearly, the safety of people using the harbour entrance has to be our first priority, but Council is very aware of the importance of the whitebait season to our community and we’ll do our utmost to limit any impacts.”
The Council’s operative resource consent allows the disking operation during daylight hours only. Depending on the progress achieved in managing the river depth, disking may continue until December, when bucket dredging operations are scheduled to commence.