Fuseworks Media

Warning signs back on beaches – Gisborne District Council

Warning signs are back up across the region’s coastline to warn beach users about the extremely dangerous nature of woody debris washing up after the weekend’s heavy rain.

It is expected to be weeks, not days, for the remainder of the wood floating in the sea to come ashore.

Harbourmaster Peter Buell asks anyone out on the water over the next few weeks to travel at a safe speed and keep a good lookout for floating logs and debris, as they can sometimes be just under the water.

Mayor Rehette Stoltz says the weekend’s rain was a big blow for our region, especially as the city, Uawa and Whangara beaches are again covered in debris after just being cleaned last month.

“What we do know is that it could have been a lot worse.

“We’d already done a lot of work removing 22,366 m3 woody debris from the Waimata Catchment area.

“Yet we saw over the weekend just how much wood still came down the Waimata River and wrapped around and dammed up against three city bridges.

“We learned so much from last time and knew for our community’s peace of mind we had to quickly mobilise the woody debris off our two main traffic bridges as soon as possible.

“We thank everyone who gave up their Sunday to do this.”

Around 65 staff from Fulton Hogan, ISO, Downer and Council helped in the removal of woody debris from the William Pettie Bridge first and then the Gladstone Road bridge.

High stacker machines were used to dislodge the material.

It is now sitting behind the railway bridge, and a drone was flown this morning to show the volume and composition of the wood.

“We will be using boats to help dislodge the debris from this bridge, as it cannot hold the weight of the machines.

“This does have the effect of pushing the debris out to sea, and it will wash up on our beaches over the next couple of weeks.

“We’d already planned to do a final sweep of our beaches around 10 December, before Christmas. This will go ahead, and talks are underway with Eastland Wood Council (EWC) as to what their contribution might be.”

Council staff were up in a helicopter today to see the damage from the air and what woody debris has mobilised.

Scours have been closed today and there is a five-day warning to not swim or eat shellfish. The region’s coastline also remains under a biotoxin warning.

Council Principal Scientist Dr Murry Cave says the landslide dam at Tauwhareparae breached over the weekend and water is flowing freely through it.

Dr Cave says large logs covered in sediment are still under Gladstone Road bridge from Cyclone Gabrielle.

“Specialist divers from the Bay of Plenty will assist us in removing these by attaching a chain in order to haul them out.”

It is estimated 1.5 million cubic meters of woody debris is still up in the hills and will require an estimated $120 million to remove.

As well, $117 million is needed to remove woody debris from around the region’s road and bridge network.

“Council doesn’t have these funds and we’ve asked the Government to help us be proactive around future risks and ensure we protect our vital infrastructure.”

Please note: The table below was before the rain over the 24 and 25 November.

  • The 10 months from January to October 2023 had 5252.4mm of rain which is still 644.6mm more than the next highest year (2022) even though the 2023 value is for 12 months not 10.
  • The highest monthly rainfall for 2023 occurred in February at 479mm. But equally significant, only 3 rain gauge sites recorded less that 100mm in that month and was one of 2 sites that recorded more than 400mm. 10 sites recorded between 300and 400mm while 13 sites recorded between 200 and 300mm. A further 30 sites recorded between 100 and 200mm for February.
  • For each year the peak monthly rainfalls reflect specific major events;
  • 2017 Cyclone Cook, 2018 Queens Birthday Storm, 2019 March storm, 2020 July storm, 2021 November storm, 2022 March storm and 2023 Cyclone Gabrielle.

    1. Notably the period 2017 to 2023 are all significantly wetter than the long term average with the annual maximum for the period 1981 to 2010 of 2355mm.
    2. Total rainfall for 2023 is likely to reach 6,000mm+ (6 metres plus) and rainfall for the first 10 months of 2023 is already more than twice the long-term average.

    2017

    2018

    2019

    2020

    2021

    2022

    2023

    Maximum annual rainfall

    3030.8

    3972.2

    3399.5

    3632.8

    3316.2

    4607.8

    5252.4

    Peak Month rainfall

    325.8

    258

    188

    235

    157

    232

    479

     

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