Clean up work has begun across Hauraki and the Coromandel Peninsula following the devastation caused by cyclones Gabrielle and Hale in previous months.
At the Criterion Bridge in Paeroa, diggers last week worked to remove piles of silt left behind by high waters.
“There were major deposits of material left after the flooding on the inside corner of the river under the Criterion Bridge,” Waikato Regional Council works supervisor Hayden McGregor said.
“This buildup significantly reduced the volume of water that can pass under the bridge. As a result of the river having to make room for itself, it also caused erosion on the north side of the river bank.
“This means there is not as much riverside berm remaining in front of the stopbank. As the stopbank protects Paeroa, the work we are doing is considered high priority – we cannot allow further erosion to happen.”
Mr McGregor said the contractors would be removing excess material on the inside corner and installing rip-rap rock to prevent further erosion of the bank.
The Criterion Bridge is the location of Paeroa’s blue flood control gates, which last month were closed “in anger” – used for their intended purpose – for the first time since being installed in 2018.
“The river came up far quicker than what was expected so it was great to be able to close the gates in half the time and with only half the crew,” Mr McGregor said.
“It’s a huge pressure situation. I’m really proud of the level of preparedness of the crew and how smoothly it went, and the monitoring of the incoming storm which allowed us to be ahead of the punch with closing the gates.”
Floodwaters rose to just 400mm below the top of the flood gates, proving how essential they were to Paeroa’s flood response.
Although the town was safe, there was still plenty of damage between the stopbanks, and the council will be picking up the pieces for some time to come.
“We are still building a picture of exactly how bad the damage to the environment is, in terms of flood protection and river management issues,” Mr McGregor said.
“The teams that are cleaning up are currently focusing on removing trees from the river as they can create dams/bridges that exacerbate flooding. Once this high priority work has been finished we can pay attention to the general cleanup.”
He said the damage appeared to be extensive along the hill streams and down on to the flats.
By ALICE PARMINTER, Public Interest Journalism funded by NZ on Air.
