Falling phosphorus levels in Swan-Canning river system encouraging

2/5/98

Falling phosphorus levels in the Swan-Canning river system are an indication that Government and community initiatives to improve water quality are on the right track, Water Resources Minister Dr Kim Hames said today.

Dr Hames said phosphorus levels had fallen at Southern River, Bannister Creek and Bayswater Main Drain in the past 10 years because of strong catchment management and local Government involvement.

"This is particularly encouraging when you consider that during this time, the population in the Perth metropolitan area has steadily increased, placing greater pressures on the river system," Dr Hames said.

"Very few places in the world have achieved these type of results in large urban areas."

Excessive nutrients such as phosphorus and nitrogen in the water are the main cause of algae blooms.

"At the Bayswater Main Drain, Belmont and Bannister Creek, communities have shown how successful working with the Government through catchment management can be in reducing nutrient inflow," Dr Hames said.

Ellen Brook is now the main source of nutrient inflow into the Swan-Canning system.

"The Ellen Brook area has mixed urban land uses, but the main problem is the sandy soils which allow nutrients to move quickly into the river," Dr Hames said.

A catchment group has been established at Ellen Brook and Government agencies are working with the community and rural landowners to reduce the flow of nutrients into waterways.

"One idea is to use a large nutrient-stripping wetland to reduce nutrients and encourage birds and other wildlife back to these waterways," the Minister said.

"The Swan River is one of the best urban river estuaries in the world.

"People can use it for a variety of recreational activities unlike estuaries in Mexico, Japan and Taiwan where waterways such as Hong Kong's Tolo Harbour and Japan's Seto Inland Sea have restricted contact recreation due to pollution.

"The Swan has very low levels of toxic materials when compared to others around the world.

"This is mainly due to having little heavy industry and strong controls on discharges since the early 1900s."

Dr Hames said while scientific research would provide better understanding, strong catchment management was the main long-term approach in the 'tool kit' to clean up and maintain the metropolitan waterway.

In-river trials, such as oxygenation, would also play an important part.

The Swan Canning Cleanup Action Plan, which would integrate all elements of the 'tool kit', would be released for public comment later this year.

Media contacts: Minister Hames office, Caroline Lacy 9424 7450

Water and Rivers Commission, Paula Wallace (08) 92780741