New Zealand: project to raise stopbank height underway at NgāteaProject Updates // February 20, 2017
The next stage of Waikato Regional Council’s multimillion dollar project to strengthen Piako’s flood protection scheme has just kicked off near Ngātea.
Work costing NZ$1.3 million started this month at the Rawerawe floodgate at the end of River Road, and will continue along the river towards the township.
It is expected to take local contractors Kerepehi Transport Limited until mid-April to raise the height of the stopbank, with crews working up to 12 hours a day, six days a week. When construction is complete, topsoil will be replaced along with grass seeding during April.
It is part of a long term project for the area which started in 2011 with this section undergoing river stability works.
The works were successfully completed this year – two years ahead of schedule – allowing the council to move to the next stage of this project, raising the height of the stopbanks.
“The existing stopbank is either at or below our desired height, and this top up is going to increase it to 500mm above the design flood level,” said senior engineer, Dan du Toit.
“It means that even when the stopbank naturally sinks over time, Ngātea’s residents will continue to be protected from the risk of flooding.
“Ngātea and the surrounding area on the Piako River is vulnerable to flooding and this project is vital to maintaining continued protection for the community to land and property as part of the Piako flood protection scheme,” said Mr du Toit.
Council operations team leader Kenny Growden said: “We have worked with the contractor to minimise the impact on Ngātea residents once construction reaches the town, but there will still be approximately 100 additional truck and trailer movements through the town each day, so people might experience some disruption.”
In the summer of 2018 the remaining portion of the town’s stopbank will be completed to Phillips Road. Upgrading will then move to the opposite bank between SH2 at Ngātea and SH22 at Pipiroa. This 8.9km stopbank will be completed over three consecutive years.
The existing comprehensive Piako flood protection scheme was developed by the Hauraki Catchment Board in 1959 and constructed between 1962 and 1979. The scheme provides vital river and coastal flood protection for a significant portion of the Hauraki Plains.
The council’s integrated catchment management directorate manages and maintains the scheme to ensure it continues to provide effective protection and security to the communities into the future.