Study shows Basslink Subsea Power Cable impact on seabed minimal

A recently published study of the 290km Basslink power cable shows that its impact on the seabed and associated organisms is “transient and minor,” the company said.

Basslink plays a key role in the distribution of power between the Australian states of Victoria and Tasmania. To protect this infrastructure, the cable was placed in a trench cut into the seabed. However, near Tasmania the cable was placed in an iron pipe conduit in order to safely pass over a 500m wide zone of rocky reef and rubble.

To oversee investigations into any ecological impact of laying and operating the cable including its magnetic and electrical fields, an independent review committee was formed. Its findings have been published in the peer-reviewed Journal of Ocean Engineering and Science.

Using a suite of data that included repeated video surveys of the cable and seabed, the study has come up with the following findings:

Off Victoria, in water depths less than 15 meters, the trench and cable were buried by sand and became indistinguishable from the natural seabed within two years.

Off the rocky Tasmanian coast, the iron pipe conduit containing the cable became encrusted by marine species similar to those inhabiting the natural reef–that process occurring within 3.5 years.

In deeper parts of the cable route (down to 80-meter water depth), it took one to 1.6 years for all traces of the trench/cable to disappear.

The International Cable Protection Committee was formed in 1958 to bring about safeguarding of international submarine cables against man-made and natural hazards. The organisation provides a forum for the exchange of technical, legal and environmental information about submarine cables. It has more than 150 members from over 60 nations, including cable operators, owners, manufacturers, industry service providers, as well as governments.

The Basslink Interconnector enhances security of supply on both sides of Bass Strait; protecting Tasmania against the risk of drought-constrained energy shortages while providing Victoria and southern states with secure renewable energy during times of peak demand.

Basslink has a number of fibre-optic assets which carry high speed telecommunication traffic. Basslink Telecoms offers a range of wholesale transmission services between Tasmania and Victoria.