Action after landfill exposed by floods

The recent flooding exposed an old landfill in Gore. Photo: Gore District Council
The recent flooding exposed an old landfill in Gore. Photo: Gore District Council
Work is under way to prevent old landfill material entering Southland waterways after recent flooding.

The old Gore landfill was exposed when floodwaters scoured the banks of the Waikaka Stream, near Hamilton Park, during the flood.

The Gore District Council has set to work installing an interim fix. The work is expected to be completed next week.

Transport Manager Peter Standring said layers of geotextile and geogrid would be placed over the exposed areas to prevent landfill material entering the river and help reduce further bank erosion.

‘‘Geotextile and geogrid is an inexpensive interim option that we can quickly put in place.’’

Fencing was being put up at Gore to keep people and animals away from the potential unstable sections of the riverbank, and weekly site inspections would be carried out.

Next week a plane will be used to conduct a LiDAR survey, assessing the affected section of the stream.

The survey would provide a complete picture about the extent of the damage and the accuracy of contour data along the stream.

‘‘The survey will give us a basis for future monitoring and a profile of the exposed areas for any engineering design solutions.’’

Last week, engineers found the Gore landfill was vulnerable to further erosion and scouring, and requiring immediate interim work.

The Mataura site, which is on the banks of the Waimumu Stream near State Highway 1, was comparatively stable and suited to a single, long-term solution.

The recommended long-term solution for Gore 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.

Mr Standring said the council was committed to minimising the impact on the environment and community.

The Waikaka walkway, at Hamilton Park, has been effected by the scouring and remains closed to the public.  

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