Strategies for protecting our coastline and other shorelines are being developed across Australia in response to current and projected sea level rise arising from our changing climate. Protection may be needed from inundation and erosion and in response to land (e.g. sandhills and shorelines) receding inward.

Concern arises for public and private assets, such as homes, surf life saving clubs, roads and other infrastructure and for the natural environment. For example habitat for plants, birds, animals will be lost as sea level rises and species will, if possible, seek to retreat from the encroaching sea.

Along the LeFevre Peninsula, while there are risks to our coast from sea level rise, there are greater risks along the Barker Inlet and Port Estuary waterways. Our Port River is tidal, mixing sea and fresh water, and is linked to creeks and channels that open up into the Gulf St Vincent.

A sea level rise (SLR) of 10cms has occurred in the last twenty years in the Port River and our community is familiar with the impact of king tides, especially if associated with major rain events that put pressure on our stormwater infrastructure.

AdaptWest, the regional climate change adaptation strategy, maps the likely extent of local inundation under 3 scenarios of 50 cms of sea level rise, 80 cms and 110 cms.

While hard engineering structures such as seawalls have been used in the past, increasingly there is interest in providing living structures that enable nature to do the engineering for us. This approach is termed ‘Living Shorelines’ and is being implemented overseas e.g. Chesapeake Bay USA and being trialled in Port Phillip Bay, Melbourne.

As a response to sea level rise ‘Living Shorelines’ have the potential advantage of their height increasing naturally once established.

The following diagrams have been supplied by Peri Coleman of Delta Environmental Consulting, from a presentation on ‘Living Shorelines’ made to the Port Adelaide Environment Forum in June 2015. (Left click on the diagrams to enlarge them.  Note: MHW means Mean High Water)

A Living Shoreline approach for the Port River and Barker Inlet

The following diagrams show steps that can be taken to protect our river shoreline:

A Living Shoreline approach to sandy beaches

While sand replenishment is widely recognised and used to protect sandy beaches, native vegetation can also contribute to dune stabilisation.

This post is one in the series Significant Environmental Issues on the Lefevre Peninsula

The Estuary Care Foundation SA, formed in mid 2016, aims to promote and undertake trials of ‘Living Shorelines’ along the Port River and in the Inner Harbour.