Terrace works halted

CONCERNS have been raised around trenching works that have started on a property near the environmentally significant Boggy Creek Geoheritage Site, prompting a visit and inspection from department officials.

The geoheritage site is otherwise known as “tufa terraces”, a rare and endangered ecological plant community.

The King Island Council has requested that trench digging stop and the Tasmanian Department of Natural Resource and Environment – Tasmanian Waterways is investigating.

It is understood the property owners had indicated that drain clearing works were needed and that boundary fencing required replacement.

Mayor Julie Arnold said to her knowledge, there were no Development Applications for the site.

“As far as I am aware the new owners are planning to run some cattle and have been replacing old fencing and fixing existing drains, and the matter is being investigated by the appropriate authorities,” Ms Arnold said.

The property owners have not responded to requests for comment.

The King Island Natural Resource Management Group (now King Island Landcare) received a Federal Government grant to protect the “tufa terraces” and coastal complex” within the area.

The terraces and coastal complex plant communities and zone extends into private landholders’ property and coastal paddocks.

The terraces and rim stone pools are delicate formations, which are nation-ally significant and listed in the Tasmanian Geoheritage Database.

King Island Landcare says the pools probably started forming 5000 to 6000 years ago.

This was when the sea level stabilised at about the level it is today.

The pools are composed of lime or calcium carbonate, which originated from the dunes just inland from the coast.

These dunes have a very high shell content.

When it rains water percolates through the topsoil becoming slightly acidic, percolates further and dissolves the lime out of the dunes and then continues to flow down towards the sea where it comes out onto the surface as a spring.

The water chemistry changes, it becomes less acidic, and the lime comes out of solution and is precipitated over rough spots such as rocks or the pool edges.

These are known as rim stone pools and they continue to grow today.

Boggy Creek tufa terraces are the best examples in Australia, which, unusually, have developed outside limestone or dolomite caves where they are normally found.

The old rocks and reefs at this site underlie vast parts of the island and are thought to be about 1000 million years old

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