Under the Murray Darling Basin lies a vast amount of saline groundwater that in many places is as salty as sea water. Salt is a natural feature of the Basin and has accumulated over the past 65 million years.

 

The Basin’s flat terrain, low rainfall and high levels of evaporation have combined to concentrate salt in the soil and groundwater.

Prior to European settlement, native vegetation helped keep the salt levels essentially in balance. However, human activities - particularly in the past 100 years - have had a major impact.

 

Agricultural development and irrigation along the River Murray, land clearance and the control of the river water by weirs and dams have caused large amounts of saline groundwater to rise and make its way into the river system.

 

The River Murray is the only “drain” from the Murray Darling Basin and provides a channel for the salt to exit the Basin.

 

About 80% of the Basin's water is diverted for consumption, principally irrigation, and so there is less flow to dilute the saline water.

 

Morgan is SA Water’s long term benchmark site for measuring River Murray salinity as it is the first major off take of our pipeline system.

 

Large quantities of salt flow down the River Murray every day. About 4000 megalitres per day flowing past Morgan can carry about 1000 tonnes of salt.

 

River salinity roughly doubles between the Victorian border and Morgan and continues to increase further downstream.

 

On average about 1000 tonnes of salt per day enter the River Murray in South Australia alone.