Ultrasound Trial

Wagga Wagga City Council is conducting a 12-month trial of an ultrasound system which aims to control cyanobacteria (blue-green algae) to safe levels in Lake Albert. The aim of the pilot project is to find a solution to keep the Lake open year-round for recreational use.

Trial start: 17 December 2018
Trial finish: 16 December 2019

WHAT IS ENVIROSONIC ULTRASOUND?

Ultrasound are sound waves with frequencies higher than the upper audible limit of human hearing. At specific frequencies, these sound waves can be used to control algae growth by inducing sono-chemical reactions in water. The Envirosonic units are solar powered and will be installed on five pontoons anchored to the bottom of the lake and will have malfunction alerts.

Blue-Green algae trial

ABOVE: PONTOON LOCATIONS IN THE LAKE

WHY SELECT ULTRASOUND TO MANAGE BLUE-GREEN ALGAE?

Ultrasound is one of several short-term treatment options available for managing algae. In addition to being efficient and cost-effective, the technology was selected because it was assessed to be best suited to the conditions at Lake Albert.

IS ULTRASOUND USED ELSEWHERE IN AUSTRALIA TO CONTROL BLUE-GREEN ALGAE?

Yes. Envirosonic installations are used at Grassy Dam, King Island, Tasmania (operated by Taswater), Candowie Reservoir, Gippsland (Operated by Westernport Water), Barren Box Dam, Griffith (operated by Murrumbidgee Irrigation) and at a lake operated by Bendigo Council, Victoria.

HOW WILL THE ALGAE LEVELS BE TESTED?

WWCC takes weekly water samples from Lake Albert, which are tested by ALS Water at their laboratory in Canberra. The performance of the ultrasound technology will be gauged against weekly lab results and the green, amber and red algae alert levels. The trial will be deemed successful if the cyanobacteria level are within 50,000 cells/mL (Amber Level) during peak summer months and 5,000 cells/mL (Green Level) during all other months.

WHY DO BLUE-GREEN ALGAE BLOOMS OCCUR?

Blue-green algae are a type of bacteria known as Cyanobacteria. They are a natural part of the freshwater environment. When it rains after a long period of dry weather, Lake Albert receives a high dose of storm water runoff loaded with nutrients, particularly nitrogen and phosphorous. This together with hot weather and still water with low turbulence, creates the conditions for an algal bloom. Algal blooms generally occur in still water rich in nutrients and thrives in dry, warm conditions.

WHAT HAPPENS AT THE END OF THE TRIAL PERIOD?

A second report will go to Council with the detailed results and a decision will be made to procure the ultrasound units.

HOW CAN YOU HELP MAKE THE TRIAL A SUCCESS?

The community can assist by following some simple guidelines:

  • BOAT USERS SHOULD NAVIGATE CAREFULLY AND AVOID THE PONTOONS
  • DON’T CLIMB ON THE PONTOONS
  • REPORT ANY TAMPERING WITH THE UNITS TO COUNCIL ON 1300 292 442
  • DON’T SWIM NEAR THE UNITS