Environment

Since European settlement, river regulation within the Murray-Darling Basin has caused a quite dramatic change to the Coorong.

Being at the end of the Murray-Darling Basin, the Coorong receives, directly or indirectly, the impact of actions and decisions made throughout the basin. There are now over 100 regulatory devices in the Murray-Darling system, including five barrages, which separate salt and fresh water close to the river mouth.

Land clearance, soil salinisation, erosion and polluted drainage into rivers have changed the water quality of the Murray-Darling system.

The abstraction of water for irrigation has altered the flow regime, resulting in a much-reduced overall flow, and diminished flooding events.

Consequently, the river system is now a steadier one. Simple habitats have replaced once complex ones, resulting in less habitat types and thus fewer species.

Reduced flows have resulted in long periods of time when no fresh water reaches the Coorong via the barrages. This causes a change in the salinity levels of the estuary, deprives it of nutrients and allows sand to accumulate inside the river mouth.

Consequently, many estuarine species, (species found at the Murray Mouth) which relied on variable, brackish conditions, are being replaced with marine species.