Emu Lake, Australia
Emu Lake was constructed from a natural swamp located in Ballajurain the City of Swan, Western Australia. It covers an area of approximately 10.5 ha (105,000 m2) and is fed by stormwaterrunoff and groundwater from the Gnangaramound. Since its construction in 1980, the water quality in the lake has deteriorated with blue green algal blooms (particularly the toxic form of cyanobacteria) becoming more dominant in recent years.
A trial application of 7 tons of Phoslockwere applied to 1/3rd of the lake on 16th/17th April 2007 to reduce the phosphorus load. Phoslock was sprayed from the shore into the lake via a hopper that mixed the Phoslock and site water into a slurry. After the success of the trial 26 tons was applied to the whole of the lake between 3-7th December 2007. On 9th/10th June 2011, a top-up application of 22.2 tons of Phoslock was applied to Emu Lake.
Based on the available data, we believe that the 2007 applications were effective in significantly reducing the concentration of bio-available phosphorus in the lake as well as the concentration of algae. However, as this lake regularly receives nutrient laden stormwaterthere was a need for a top-up dose in 2011. It is also likely that future regular (yearly) doses will be needed to ensure that the P concentrations are kept low, as to not promote algal blooms.