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04/29/2009

Vegetation holds the key to better water quality

Griffith University researchers have recently concluded a major three-year study that will help protect water quality in South East Queensland and reduce soil nutrients entering our waterways.

Dr Michele Burford from the Australian Rivers Institute said the findings identified the source of the nutrients which trigger troubling algal blooms in dams.

“When soil becomes wet, significant amounts of phosphorous is released in a dissolved form and flows into the Brisbane River and then into water reservoirs, promoting algal blooms,” Dr Burford said.

“Algal blooms deteriorate water quality in dams, reducing the level of oxygen in water and affecting the health of ecosystems including fish.”

Dr Burford said farmers, water managers and scientists needed to work together to resolve the problem.
“We need to take a holistic approach and collaborate with farmers and water managers to stabilise the soil on hill slopes and maintain good vegetation cover to slow water movement and increase infiltration.”
Dr Burford said this finding would change the way degraded catchments would be rehabilitated.

“It is not enough just to restore degraded land along the river to prevent soil movement, we need to restore the water route to the river if we are to resolve this problem effectively. 

“Trees and other vegetation along the rivers, which act as a buffer trapping soil particles, cannot effectively filter the dissolved phosphorous.

“We need to hold the phosphorous at its source, which can only be done by preventing soil erosion and absorbing more rainfall into the soil and decreasing surface runoff.

“Over-grazing, especially during drought, is a major problem as it leads to greater surface runoff and higher dissolved phosphorus entering our dams.”

This study has been funded by Australian Research Council Linkage Project grant and was undertaken in collaboration with seqwater, the Healthy Waterways Partnership and CSIRO.

Dr Burford is speaking at Griffith’s inaugural Virtual Research Week, an online event from May 5-8. See www.grifffith.edu.au/virtualresearch for details.

Griffith's Australian Rivers Institute is home to more than 120 scientists and research students, making it the largest concentration of university-based water researchers in the country.


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