Water table salt levels spike
OUR water table is salty and it’s forecast to get saltier.
This could take a huge toll on citrus and small crop growers in the Burnett catchment area in coming months.
“Salinity levels have spiked to the highest we have seen in the past 10-15 years, possibly longer, which is the last thing landowners want right now,” Burnett Mary Regional Group soil scientist Peter Wilson said.
“It’s just one thing after another, we have the flood, then the drought and now we’ve got this flaming salty water!”
High salt levels are the result of the water table rising during the past couple of wet years.
“The inland Burnett landscapes are naturally high in salt, so when the water table comes up the salt is mobilised, making the water table salty,” Mr Wilson said.
“We have leakages in our water table, so this salty water then flows into river systems making them more saline as well. The leakages tend to be at lower parts of the landscape, the dead vegetation you see in gullies is often due to salt.
“Because the Burnett River is so incised into the geology, it takes up a lot of this leakage.”
With dry weather predicted over the next few months more fresh water is going to evaporate, making the salt concentration in the rivers higher.
“The whole Burnett catchment area will be affected, but the middle to lower areas around Mundubbera and Gayndah are going to be the worst,” Mr Wilson said.
If horticulture crops are irrigated with salty water it burns the foliage, and salty water in the soil restricts water uptake and stunts the plants’ growth.
But Mr Wilson said there were management options to work around the salt problem.
“Irrigating at night is good because there is no evaporation then, so the foliage doesn’t get burned,” he said.
“Landowners could dilute river water with fresh water, or water only under the canopy to avoid the foliage, and apply soil conditioners. But it is a very hard issue to manage and it can be costly.”