Results are back from validation testing on the first dredged section of the Kopeopeo Canal and they are showing sediment quality is now below the remediation target.
Project Manager Brendon Love said that dredging is continuing and it was reassuring to get the results back from the first section.
“Those first validation results are important because it means that the methodology is working well and we can be more confident as the dredge moves forward,” Mr Love said.
The Project is using a cutter suction dredge to remove contaminated sediments from the Canal and transport them through a pipeline to lined containment sites. From there, the sediment in the geotextile bags is dewatered and remains in the geobags within lined cells to be bioremediated at a later stage.
“There have been some other key milestones as well – The Contractor successfully crane-lifted the dredge over the first private Canal crossing. The Contractor also used a smaller ‘sand bug’ to suction dredge to remove sediment from around and under that bridge where the large dredge doesn’t fit. It was good to fine-tune that process as there are a number of crossings throughout the 5km length,” Mr Love said.
While the barge and cutter suction dredge move forward, significant progress is being made on other aspects of the Project.
Work is progressing well on the second containment site near Keepa Road at the other end of the Project area. The road area has been reformed, vegetation removed, fencing started and rock armouring of the site carried out. Public access options are still being assessed but the Project Manager said the team hoped to have a new public walking track in place shortly after the site boundary fencing is completed.
“It was also good to see our flood management planning mostly working well through the recent high rainfall event. We have a few things to fine-tune but overall the water was pumped west as planned,” Mr Love said.
Dredging will continue along the Canal during the coming months and validation testing will be carried out behind each dredged section. At the end of the Project, sediment will have been removed from 5.1km the Canal, leaving the waterway in a healthier state for future generations.
The sediment quality target is below 60pg/g I-TEQ (i.e. 60 parts per trillion). More detail on what this target means and how it compares with national and international standards is available on the website.
Detailed information on the Kopeopeo Canal Remediation Project can be found at www.boprc.govt.nz/kopeopeo
The Bay of Plenty Regional Council (Rivers and Drainage Group) is working with the community to clean up dioxin-contaminated sediment in the Kopeopeo Canal. The canal was contaminated between the 1950s and late 1980s as a result of stormwater discharges from a former sawmill, which treated timber using Pentachlorophenol (PCP). While unknown at the time, PCP imported into New Zealand for use in the timber processing industry also included a percentage of impurities that contained dioxins.
The project is taking a staged approach to remove, safely store and treat up to 40,000m3 of sediment.
Consent was granted for works to begin in 2014, subject to significant conditions. The community raised a number of concerns about the original methodology (excavators and trucks) for removal of the sediment. Following a successful pilot study of a new method in October 2015, an application was lodged in May 2016 to vary the existing consent so that the sediment could be removed by a cutter suction dredge and transferred by pipeline to the containment sites. This new method virtually eliminates the heavy traffic and potential for spillages and associated dust generation, and brings improvements to the containment site design which reduces potential groundwater and flooding related effects.
The variation to the consent was approved in September 2016 and a contract awarded to Envirowaste Services Ltd in December 2016 to undertake the remediation works
The project is jointly funded between Regional Council and the Ministry for the Environment’s Contaminated Sites Remediation Fund.
For further media information, please contact Abby Tozer, Communications Partner, on firstname.lastname@example.org
A crane lifts the wheel house prior to the barge lift