How Algal Activity and Water Quality Have Changed Across the Gippsland Lakes
Gippsland Lakes And Its Environmental Concerns
Gippsland Lakes are a network of lakes, marshes and lagoons covering over 600 square kilometres, making a rich ecosystem for different plants and animal species, as well as being a perfect tourist destination. However, in 1889 Gippsland Lakes changed from being naturally fresh-brackish to estuarine when an artificial opening connected the lakes to Bass Strait. Overtime this has created an environment that favoured nutrient retention and algal growth. This then lead to Gippsland Lakes suffer periodic blooms of toxic cyanobacteria that close the waterway for recreation and fishing. Hence making it important to better understand and manage these environmental issues.
Average Chlorophyll-a at Surface and Below Surface
Figure 1. Average Chlorophyll A at Surface and Below Surface
Average Chlorophyll-A Values Early (1990-2004) vs Recent Periods (2005-2025)
Figure 2. Average Chlorophyll-A Values Early(1990–2004) vs Recent (2005–2025) Periods
Water Quality Parameters VS Year
Figure 3. Trends in Water Quality Parameters (1990–2025)
Key Insights
Total nitrogen seem relatively stable over the years, with Lake King North and Lake Victoria showing slight fluctuations around the 1000 mark, while other lakes like Lake Reeve West exhibit occasional spikes
Phosphorus levels appear to fluctuate more significantly, with Lake Reeve East showing high peaks, especially in the earlier years (1990-2010), while Lake King North and Lake Victoria remain relatively stable with some fluctuations in Phosphorus
Secchi depth shows significant variations with Lake Victoria and Lake Reeve West having more fluctuations in clarity over the years, Lake King North seems to have the most consistent clarity, whereas others like Shaving Point show a decline in clarity after 2010
pH values show a general slight decrease over time in most lakes, Lake King South pH appears to drop the most from around 8.5 to 8.0 over the past 30 years
Lake Wellington has the highest average Chlorophyll A in both surface and below surface, 16.01 and 16.33 respectively
Lake Wellington was also the only site where the average Chlorophyll A content was higher in below surface rather than at the surface
References
EPA Water Sciences. (2025). EPA Gippsland Lakes Water Quality Data 1990–2025 [Data set]. Discover Data Victoria. https://discover.data.vic.gov.au/dataset/gippsland-lakes-water-quality-data
Visit Victoria. (2018). Gippsland Lakes, Victoria, Australia. Visit Victoria. https://www.visitvictoria.com/regions/gippsland/see-and-do/nature-and-wildlife/lakes-and-waterways/gippsland-lakes
Cook, P., & Smith, J. (2024). Floods, fires and phytoplankton: some perspectives on water quality in the Gippsland Lakes. Proceedings of the Royal Society of Victoria, 136(1). https://doi.org/10.1071/RS23020“
CSIRO. (2022). Gippsland Lakes Ramsar site vulnerability to bushfire and climate change. CSIRO. https://www.dcceew.gov.au/sites/default/files/documents/gippsland-lakes-ramsar-site-vulnerability-bushfire-and-climate-change.pdf