Sand mining

Storms expose true environmental values

Two storms hit the metro coast in 2021 – the first on the 31st of May and the second shortly after on 24/25th June.

The scale of their intensity is disputed. Departmental staff, taking a long term view, say they were relatively rare. Others view such events as consistent with global warming predictions of storms of increased magnitude and frequency.

What is beyond dispute is that the coastline between the Largs and Semaphore jetties has been mined consistently since 2019.

Perhaps it’s time to let nature speak.

The Coast Daisy Bush ( Olearia axillaris) is a relatively slow growing plant found behind the fore-dune. The images below, taken on a section of the dune north of the Semaphore jetty show the demise of just one of a number of these plants during the second storm.

  • Olearia hanging by taproot
A coastal rosemary holds on by a taproot developed over a decade, until it finally snaps , and is swept away. The following morning even the Knobby Club Rush plants in the foreground had disappeared. 24 June 2021

This evidence shows the area was at least a decade old – clearly an unusual event. This area of the coast has been mined consistently since 2019. – in fact, mining was taking place prior to and after these storms.

The location, adjacent to a collection stockpile parallels the situation at Largs Bay where over extraction occurred at locations close to a collection point, minimising the distance machinery had to travel.

A valuable stretch

A recent vegetation survey, ( Flora survey of dunes. Semaphore South to Largs North) conducted for the Department identified the area concerned (11 in the image below) as one of the best areas along this section of the coast.

Illustration from Flora survey of dunes. Semaphore South to Largs North. Area 11 is classified as one of the best sections surveyed, having indigenous:exotic plants in a ratio of 80:20

A section of the fore-dune has now been eroded killing some vegetation. More importantly this breach will allow further inundation with the next storm.

The response

Participants raised the issue at the Department’s liaison group, the Semaphore Working Group. The Department’s response was that this was completely natural, “expected” and would recover. Moreover, they claimed damage was limited to low grade vegetation in Area 12.

It’s difficult to know what to do in the face of adamant denial in the face of clear physical evidence. Such behaviour can only lead to distrust.

Meanwhile it was all sytems go to tend to the Department’s infrastructure at Semaphore South.

Bunting hastily erected after the 31 May storm in 2021 at Semaphore South. The Department established the “dune” to counter the erosion caused by the Point Malcolm breakwater by carting 37,000 cubic metres of sand from Largs North in April 2020. In the 16 months to September 2021 a further 33,000 have been mined to maintain it.

Bunting was erected (at rate payer’s expense) and the wheels immediately started turning to effect a repair.

Whatever values the Department FOR ENVIRONMENT and Water might have seem to be lost as they filter down to the ground.