Good things come in trees: How Stanwell is tackling dryland salinity

12 December 2022

The team at Stanwell Power Station is collaborating with Tunuba, a local land management agency, to get to the root of the problem of dryland salinity by planting native trees.

Dryland salinity is the build-up of salt in the soil surface of non-irrigated areas. It occurs as the result of rising groundwater tables, which are the upper limit of where water is found underground.

As groundwater tables rise and groundwater seeps to the surface, it brings salt with it. Even after the soil surface dries out, the salt is left behind, which eventually results in increased soil erosion and reduced plant growth and water quality.

Stanwell Power Station Environmental Advisor Kelly Thompson says addressing dryland salinity is part of Stanwell’s long-term land stewardship efforts.

“Salinity is a problem in the wider Rockhampton region, not just in this spot,” Kelly explains. “But we want to do what we can on our land to have a positive impact.”

Kelly says planting trees can provide a long-term solution for the issue of dryland salinity.

“Trees draw water through their roots, which lowers the groundwater table,” she says. “Rainfall leaches the salt down through the soil profile and away from the root zone. Gradually, over time, the area affected by dryland salinity will improve as a result of this.”

Kelly carefully chose the trees that would be planted, to ensure they would have the desired effect.

“You can’t just plant any old trees in areas that have been affected by dryland salinity and expect them to grow,” she says.

“I chose the species. They had to be trees that were indigenous to Australia, and they had to be able to handle being waterlogged for a period of time. They also had to be tolerant of salt, which narrowed down the possibilities, because most trees and plants can’t grow in saline conditions.”

Ultimately, there were a limited number of trees that would fit the bill. The species Kelly chose to plant were Melaleuca leucadendra (Weeping Paperbark), Casuarina cunninghamiana (River Oak) and Eucalyptus moluccana (Grey Box).

Stanwell engaged Tunuba Pty Ltd to assist with planting 70 seedlings in areas. Tunuba – which is the traditional name of the Fitzroy River for the Darumbal People – is a joint venture between the Darambul People and CQG Consulting that delivers a range of land management and professional services to support the livelihood and economic development of local Indigenous people and businesses.

Stanwell works proactively to build relationships with Traditional Owners in the communities in which we operate. These relationships are built over time, through trust, mutual respect and ongoing, authentic and transparent engagement.

“We had a few general areas picked out where we wanted to plant the seedlings, but the Tunuba team helped us find the most appropriate site to plant them and gave us some advice on the most effective ways to plant them,” Kelly says.

“They were fantastic to work with, and we hope to be able to call on their expertise to help us plant more trees in the future.”

The area where the seedlings were planted will now be closely monitored to determine the success of the project.

“This is something of a trial plot,” Kelly says. “We’ll look at the survivability of the trees. We already have a groundwater monitoring program that runs throughout the entire site, and in the specific area where the trees have been planted, we’re using bore logs to measure the water level.

“It’s not going to happen overnight. It’s going to take a long period of time, but we should gradually see the groundwater level in that area get lower, which will reduce the salinity.

“If that happens, it’ll be a great result for the site, and we can apply these learnings to the other areas we have earmarked for tree planting.”

From little things, big things grow…