Coal Tar Contamination Delays Greymouth Floodwall Upgrade

Saturday, 8 June 2024, 6:36 pm
Article: Brendon McMahon - Local Democracy Reporter

The discovery of buried coal tar has caused a blip in Greymouth's flood protection upgrade.

At the same time, a budget shortfall has emerged in the $2.6 million project which could reduce the scope of the stopbank improvements aimed at protecting the town in a 1:150 year flood.

Infrastructure Resilience Group programme manager Scott Hoare told LDR on June 6 the unearthed coal tar was near the entrance to Anzac Park. It had caused a delay of two weeks after the contractor was forced to stop work as they found a solution, he said.

Samples have been sent for analysis, but so far indications show there is no serious risk to health.
The history of the tar at the site was not yet clear.

The site, adjacent to Sawyers Creek, is near what was the historic Greymouth War Memorial swimming baths.

Mr Hoare told the West Coast Regional Council's Infrastructure Governance Group on June 4 the issue was not "that huge".

But a strategic approach included the contractor MBD having to up sticks while the coal tar was investigated.

Mr Hoare said the contractor MBD would meantime start work west of the contamination site, on the existing floodwall by Greymouth Port, west of Prestons Road.

Mr Hoare said they would either return to complete the Anzac Park section later or finish the Prestons Road east floodwall section before going back to Anzac Park.

He told councillors at their June 4 meeting that two Greymouth area dump sites able to take coal tar had "declined to take it".

Enclosing the 30,000 cubic metres of material within Anzac Park was another option being explored.
He agreed with a summation from Cr Brett Cummings, it only represented "a couple of truck loads".

The last time coal tar delayed public work in Greymouth was in mid-2017 when the $1.7m Greymouth Townsquare build was interrupted by several months. It cost the Grey District Council nearly $100,000 to remediate at the time.

Meanwhile, a shallow undocumented water pipe unearthed on May 8 had also delayed the project's first stage at Anzac Park.

Mr Hoare said it took a fortnight to rectify following "repeated requests" to the district council who had advised it had to be rectified by their approved contractor.

Cr Peter Ewen said that was "pretty disappointing" given the floodwall was administered in a partnership approach.

The budget shortfall for the entire floodwall upgrade was also flagged this week.

Mr Hoare told councillors the project scope was at now risk due to the budget and delays.
While stages one and three were progressing, stages two, four and five were "being reviewed".

He said the unforeseen ground conditions meant "additional costs" and to date $875,725 of a total budget of $2,605,822 had been spent.

Infrastructure Governance chairman Frank Dooley wanted to know if the shortfall had been addressed yet at the Greymouth Joint Floodwall Rating District Committee.

The rating district is due to meet on June 26.

Council chief executive Darryl Lew said talks with the Ministry of Business, Innovation & Employment's infrastructure division Kanoa had started around possible new funding for the scheme, in line with the Before the Deluge initiative, which might benefit Greymouth.

Cr Dooley asked how the effectiveness of the floodwall might be compromised if the delayed staged improvement did not proceed as planned.

Mr Hoare said the floodwall improvements would increase freeboard anywhere by 50 to 500ml along the floodwall, but without further funding, "we won't have a consistent level of service".

The scheme currently had 400ml of freeboard, but some sections were at "more risk".

Freeboard is the amount of designed leeway above the wall's base design level to accommodate a 1:150 year flood.

In response, Cr Dooley called for a further risk assessment of the implications of not doing any further work.

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