Salinity Management Measures
About the Salinity Management Measures program
The Salinity Management Measures project was part of the SARFIIP and aimed to reduce the amount of salt that enters the Pike Floodplain. It complements the work completed through the Pike Floodplain Restoration Project to protect the wetlands and floodplains.
This project has been completed through a two staged approach. The first round of works commenced in June 2018 along the Sturt Highway near Paringa and involved installation of a series of groundwater pumping wells and monitoring wells. The second stage of works commenced in August 2019 and comprised of a pipeline that connects the pumping wells together and moves saline groundwater away from the floodplain.
In total the project included construction of approximately 15 km of new pipeline (completed in two parts) and 35 wells approximately 50 m deep on the highland and floodplain. This prevents up to 120 tonnes of salt entering the Pike Floodplain each day from groundwater in the highland and around the floodplain and contributes to the long-term management of salinity in the Pike area.
The groundwater management wells pump the salty water away from the floodplain to a disposal basin located at Noora. Reduced levels of salt help to restore and protect the floodplain environment by improving water quality for native flora and fauna, and for local and downstream irrigators.
The works completed through the Pike Floodplain Restoration Project involved the construction of environmental regulators and associated infrastructure that is used to deliver environmental water to the floodplain. This is helping to improve the condition of the plants and trees by providing water for the environment more often. It allows for more frequent managed floodplain watering events to occur and over time will help flush out the high levels of salt which have accumulated across the landscape over the past century.
Why has the salinity increased?
River regulation (controlling flow using locks and weirs) of the River Murray since the 1920s, vegetation clearance and irrigation development on the highland has caused naturally saline groundwater beneath the floodplains to rise. As a result, the root zone of vegetation is increasingly exposed to high salinity.
The frequency and duration of floods, which previously leached salt away from the plant root zone, has also reduced. The combined effect is long-term salt accumulation in the floodplain soils, groundwater and surface water.
Will the salinity increase in the river during a floodplain watering event?
Over time we expect to see water quality improve in the Pike River and Mundic Creek waterways due to these works. Any watering event, whether natural or managed comes with the risk of changes in water quality. Watering events to date have shown that managed floodplain inundations are resulting in a temporary increase in salinity both during and after an event. The potential magnitude of any salinity spike is determined and communicated to stakeholders prior to any inundation. Adaptive management is reducing the magnitude and/or duration of salinity spikes during an event. Repeated operation of the regulator to enable floodplain inundation will, over time, reduce the build-up of salt in the soil profile.
Department for Environment and Water.
SA Water, Pike Community Reference Committee, Pike River Land Management Group, Renmark-Paringa Council and Renmark to the Border Local Action Planning.