Wetland sends phosphorous levels south

Water monitoring in the Cox Creek Catchment in the Adelaide Hills has revealed up to an 80% reduction in phosphorous levels over the last decade. The positive results are credited to an important project by SA Water to improve the quality of inflows to Mount Bold Reservoir.

With high levels of nutrients like phosphorous previously flowing from farming properties upstream, down the small catchment and into the Onkaparinga River, in 2006 crews constructed a natural wetland at the Woodhouse Activity Centre and a separate sedimentation basin at the nearby Brookes Bridge.

SA Water’s Manager of Catchments, Wastewater and Environmental Science, Jacqueline Frizenschaf, said the initiative traps and removes large amounts of sediment from the creek before it flows into metropolitan Adelaide’s largest drinking-water storage.

“Monitoring the balance of nutrients in our waterways is an important step in maintaining the taste and odour of our water, with phosphorus in particular a potential driver of algae which leads to extra work for our water treatment plant operators,” Frizenschaf said.

“The end result has proved to be one of the most significant catchment measures of its kind in the Mount Lofty Ranges, with around one to two tonnes of phosphorous removed each year from the water course.

“Having a functioning natural environment is critical to the health of our water catchments, which help ensure the water quality in our reservoirs is safely and cost-effectively maintained for our customers,” she continued.

The proactive initiative was a collaboration between SA Water, the Environmental Protection Authority, Scouts SA, the Adelaide and Mount Lofty Ranges Natural Resources Management Board and the wider Piccadilly Valley community.

The General Manager of the Woodhouse Activity Centre, James Sellers, said SA Water’s efforts had made a significant impact on improving the facility’s natural outlook.

“Having a native ecosystem on our property has become an extremely important educational feature where school groups, scouts and the wider community can study water birds and other aquatic wildlife thriving in their natural surroundings,” he said.

“This is now a highly valued and tranquil natural area for the Mount Lofty Ranges, and we look forward to working with SA Water on this site well into the future.”

Image credit: ©Tom Roschi Photography