Thirteen projects have been carried out under the initiative to investigate the effectiveness of engineering solutions to combat salinity in the Wheatbelt.

The projects investigated methods such as deep drainage, groundwater pumping, and farm-scale evaporation basins to help farmers better manage salinity at Dumbleyung, Tammin, Bodallin, Pithara,

Morawa, and Beacon.

Research also evaluated the effect on receiving environments of acid and saline drain discharge, and the most effective methods of treating and managing the waters that come out of such drains and pumping projects.

“This has been a very thorough investigation into the effectiveness of drains to counter salinity,” Mr Ruprecht said.

“It included drains up to three metres deep and extending for 22 kilometres, with water from two of the drains collected in evaporation ponds.

“There’s no doubt digging deep drains to counter salinity can work.

“At our Dumbleyung study site monitoring showed that groundwater levels were lowered adjacent to the drain, and the water discharged by the drain was removing salt.

“The EEI has also demonstrated that when planned properly with a clear objective, drains can significantly lower the water table enough up to 250 metres away.”

Mr Ruprecht said digging drains is expensive and some farmers baulked against drainage as an option for managing salinity because of this high cost.

He said farmers needed to determine issues such as whether they wanted to lower the watertable across a catchment, or make specific saline sections of paddocks grow crops again, and where to dispose or manage the waters from a drain.

“Several thousand kilometres of deep and shallow drains have been constructed in the Wheatbelt in recent years but no-one has scientifically looked at how effective they are, what precautions should be taken, and the dangers involved in simply moving salty water from a salinity-affected farm further downstream or into a neighbour’s land,” Mr Ruprecht said.

“This sort of salinity research and development is important to ensure that property owners can decide how best to spend their money and time to fix salinity on their land, without creating potentially worse problems downstream.

“One of the messages to arise from the EEI is that engineering solutions such as deep drainage are really only one tool in our toolbox when it comes to managing groundwater levels and fighting salinity.”

The Engineering Evaluation Initiative is drawing to a close and four final reports on deep drainage are being compiled along with the findings of another nine EEI projects.