Adelaide coastal waters study

Providing an integrated understanding of the causes of water quality decline, seagrass loss and sediment instability along Adelaide’s near-shore coastal waters.

25 February 2008 | Updated 14 October 2011

Growing concern about Adelaide's coastal environment
An integrated view to guide future management
Final report findings
Working together for an integrated understanding

Growing concern about Adelaide’s coastal environment

The Adelaide Coastal Waters Study (ACWS) was a A$3 million research program initiated in 2001 to provide an integrated understanding of Adelaide's coastal system.

The six-year study investigated the causes of water quality decline and the loss of more than 5 000 hectares of seagrass in Gulf of St Vincent, adjacent to Adelaide's shoreline, since the mid 1930s and 1940s.

An integrated view to guide future management

The Adelaide coastal ecosystem is unique because of interactions between:

“Water quality improvement plans, coupled with reduced volumes of storm and wastewater inputs were found to have made a positive difference to Adelaide’s coastal environment.”
Professor David Fox, Director, Adelaide Coastal Waters Study.

seagrasses
beach and near-shore morphology
sea-floor organisms
nutrients and toxicants
water quality.

In 2001 the South Australian Government initiatied the ACWS to better understand these interactions and the processes involved.

The main research themes and issues which were specifically investigated by the study include:

the fate and impact of nutrients (nitrogen and phosphorus), and other contaminants implicated in seagrass loss
stormwater and wastewater inputs
seagrass ecology to identify what causes seagrass decline, the prospect of seagrass regrowth and the implications of seagrass recovery
how physical processes (such as wind, tides, currents and temperature) operate on a local and gulf-wide scale
sediment sources and the role of sediment in seagrass loss.

Final report findings

The study found that many years of near-continuous inputs of nutrient-rich, turbid, and coloured water and wastewater have resulted in significant changes to and degradation of Adelaide’s coastal marine environment.

Nitrogen loads were likely to have played a key role as an enriched nutrient, with widespread seagrass losses reported after loads increased to about half the present levels.

Encouragingly, the water quality improvement plans which have been in place over the past ten years, coupled with reduced volumes of storm and wastewater discharged to the sea have made a positive difference.

However, it may take at least 20 years for seagrasses to regrow and large scale recovery of seagrass meadows requires continued, lasting reductions in coastal inputs and a replanting effort.

The AWCS Final Report outlines 14 recommendations which aim to guide future management actions to enable this regrowth and recovery.

Working together for an integrated understanding

The ACWS study, co-ordinated by CSIRO, was a collaboration of more than 60 researchers from across a range of Australia’s research organisations and could not have been possible without the resources committed by all the stakeholders.

The Steering and Scientific Committee partners include: