Community Connect Issue 49 December 2022

LAKE AINSWORTH AERATOR TRIAL

Blue green algae has long been an issue in Lake Ainsworth at Lennox Head.

Council is trialing the use of an aerator 24 hours a day, rather than 12 hours a day, to see if this improves water quality and reduces algal growth in Lake Ainsworth.

Phase 1 January - February 2022

Phase 1 was carried out during the summer months of January and February 2022 and was intended to continue through to Autumn, however sampling could not continue due to extremely high lake levels following the February - March floods.

Phase 1 of the trial showed marked improvements in water quality with reduced concentrations of nutrient - particularly at the surface of the lake.

Phosphorus showed the greatest reduction, while chlorophyll and cyanobacteria concentrations were also reduced.

This reduction in nutrient is likely to have contributed to reduced levels of cyanobacteria and algae. The climatic conditions at the time, including above average rainfall and cloudy, cool conditions, are also likely to have created less favourable conditions for algal growth.

Phase 2 September 2022 - May 2023

Phase 2 of the monitoring trial commenced in September 2022 and will run until May 2023.

Phase 2 will continue into Autumn to confirm results over a longer period and varying season and climatic conditions.

The full reports of the Phase 1 and Phase 2 monitoring trials will be made available on Council’s website and a final report will include recommendations for future management of the aerator regime in the lake.

This project is identified as a high priority action within the Lake Ainsworth Coastal Management (CMP). It is funded by the NSW Coastal and Estuary Grants Program and Council.

For more information visit ballina.nsw.gov.au/HealthyWaterways