Gore District Council applies for $1m funding to fix exposed landfills

Friday, 8 May 2020

Buried rubbish was exposed when the Waikaka Stream flooded in February. The rubbish is from an old landfill near Hamilton Park in Gore. (File photo)

The Gore District Council has applied to Civil Defence for more than $1 million in funding for temporary repairs to two landfills that were exposed by floodwaters in February.

A draft Civil Defence claim, which will be tabled at a full council meeting on Tuesday, says the recovery costs for temporary repairs to the old Gore landfill was estimated to cost between $700,000 and $950,000, and recovery costs for temporary repairs to the Mataura landfill was estimated between $200,000 and $400,000.

A State of Emergency was declared in Southland in February because of flooding and at the time 2400 residents from Gore, Mataura and Wyndham were evacuated from their homes.

The Gore landfill was exposed by the Waikaka Stream when it flooded, while the Mataura landfill was exposed by the Waimumu Stream.

The report says both sites are critical assets, and the stream bank failure and exposure of a closed landfill failure has health and life safety implications for down stream users of water.

* Old landfill sites at Gore and Mataura pose environmental risk

* Gore's old landfill exposed by floodwaters

The remediation works were instructed to be carried out by a Civil Defence Controller.

Gore District Council transport Manager Peter Standring (right) and Landpro surveyor Hamish Weir (left) at the old Gore landfill site, which was exposed by floodwaters during Southland floods. (File photo).

At Gore, the council was directed to conduct a professional risk assessment, which was a top priority, and develop a remedial plan for the stream bank.

The council staff worked with consultants, a planner and Environment Southland staff to develop and implement the best practical solution to contain the exposed river bank and provide interim barriers to future flood events, as well as contain landfill material.

About 400m of embankment containment across two sites was needed in Gore.

The eventual work included battering of the riverbanks, then capping with a clay layer, geotextile/geomat, then placement of rock riprap.

The report says it was decided the council should engage a consulting engineer and a consulting planner for the survey and lab testing of the contaminants all in preparation for retrospective resource consents.

The final extent of the solution will be determined after the containment work is completed on both sides of the stream, and subsequent leachate analysis and approval by the regional council.

At Mataura, a team was mobilised to develop and implement the best practical solution to contain the exposed river bank and provide interim barriers to future flood events as well as contain landfill material and leachate. Approximately 80m of embankment containment across the site is needed.

The work will require a similar response to the Gore landfill, and the final extent of the solution is to be confirmed, the report says.

A council press release issued on February 18 said the recommended long term solution for the Gore site was for gabion baskets to be placed along an extended section of the stream to avoid further erosion in another section of the landfill.

A combination of gabion baskets and filter sock or edge savers was recommended for Mataura, the press release says.

Last week, the Insurance Council of New Zealand said $19.7 million had been received in insurance claims from heavy flooding that hit the region.