Mildura Riverfront Shared Path - Salinity

What is salinity?

Salinity refers to the amount of salt present in the soil or water. Salt is a natural feature of many Australian landscapes, however increases in salinity caused by rising groundwater levels can damage the environment.

What causes high salinity?

Rising groundwater can be caused by a number of human activities including:

• the removal of deep rooted native vegetation and replacement with shallow rooted annual crops and pastures;
• inefficient excess irrigation; and
• river regulation.

Locally, salinity has been recognised as a major threat for some time.

It was described by the Land Conservation Council (LCC) in 1989 as “the single greatest threat facing Victoria’s environment”.

What are the effects of high salinity?

Analysis of salinity in the Murray River showed that a large proportion of the salt in the Victorian section is stored in the floodplain, which has severe implications for floodplain health. These impacts are evident along many parts of the riverfront reserves, where river red gums in particular show signs of stress and in some areas have died. Revegetation attempts often fail in soils with high salinity.

Salinity also affects water quality, although these effects may be less visible at lower concentrations. Degraded water quality due to the impacts of salinity is identified as one of the main issues in the Murray-Darling Basin.

What is being done about it?

Salt interception schemes are large scale pumping schemes that divert saline groundwater and drainage water before it enters the river. In most cases, a bore and pump system extracts the groundwater and pumps it to a salt management basin some distance from the river.

Since 1988 the states of New South Wales, Victoria and South Australia together with the Australian Government, have funded the construction of salt interception schemes. These schemes prevent approximately half a million tonnes of salt from reaching the Murray River every year.

Lake Ranfurly

Lake Ranfurly is one of the local salt management basins that saline ground water is pumped into before it enters the Murray River.

Although Lake Ranfurly is used as part of a salt management scheme, it is listed on the Directory of Important Wetlands in Australia for it’s significant bird life. It supports a very large and diverse range of waterbirds. A total of 117 bird species have been recorded including 26 species considered threatened or listed under the international migratory bird agreement.

Mildura Riverfront Shared Path

Published with permission of Mildura Rural City Council