Gravel loss from rivers a concern

Niall Watson
Niall Watson
Fish and Game Otago is keen for contractors to take gravel from consolidated sites, including through quarrying, rather than continuing the "contentious" practice of removing it from Otago rivers.

Fish and Game chief executive Niall Watson said contractors generally had followed more sustainable practices involving gravel extraction over the past 10 years.

This had been partly because of the approach taken by the Otago Regional Council and growing awareness by contractors of the wider environmental issues.

However, he was concerned that problems involving fragmented removal of gravel from rivers near roading projects had increased over the past six months, he said in an interview.

Removal of gravel in an "environmentally unsympathetic manner", including from rivers which were already depleted by previous extraction, could be ecologically damaging, harming trout, salmon and other fish habitat, including spawning areas, he said.

Fish and Game wanted to work collaboratively with roading contractors, and ultimately preferred that gravel was not removed from river beds, but taken from some river terraces or by quarrying elsewhere.

The organisation planned to discuss the situation with the Otago Regional Council and Department of Conservation next month.

In a report to a recent Fish and Game Council meeting, environmental officer Peter Wilson said gravel had been extracted from Otago rivers for more than 100 years and, in many cases, there was "little gravel left".

Such extraction had always been a "contentious issue", particularly in rivers that lacked a long-term sustainable gravel supply.

Combined with other activities, this had contributed to a decline in "fish habitat values" in the rivers concerned.

Rivers particularly affected were the Clutha, downstream of the Roxburgh Dam, the Pomahaka, Taieri, Shag, and Silverstream.

The approval of resource consents for contractors to take gravel from these rivers had been a "challenging issue" in the past, as in most cases there had been a lack of information on the sustainability of gravel supply.

Instead of consolidating gravel sites across the industry in Otago, there had recently been a rise in taking gravel from sites close to roading projects.

"In many cases, what is occurring is the opposite of what should be happening," Mr Wilson said.

Fish and Game staff had generally declined "affected party" approval for the required consents, where gravel-depleted river systems were involved, unless an applicant could prove long-term sustainability of supply.

An exception was where a clear river management or public safety need could be identified, such as a gravel build-up at the Rees River bridge, which could become a public safety issue, he said.

- john.gibb@odt.co.nz

 

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