Analysis of the mixing processes in the subtropical Advancetown Lake, Australia

- Long-term analysis of chemical, physical and meteorological data for a subtropical lake.
- Investigation of the mixing dynamics in the subtropical lake in the Southern hemisphere.
- Advancetown Lake typically exhibits eutrophic, warm and monomictic characteristics.
- Vertical mixing processes are driven by diffusion.
- Storage volume and temperature transitioned the lake to a meromixis state in 2013.

SummaryThis paper presents an extensive investigation of the mixing processes occurring in the subtropical monomictic Advancetown Lake, which is the main water body supplying the Gold Coast City in Australia. Meteorological, chemical and physical data were collected from weather stations, laboratory analysis of grab samples and an in-situ Vertical Profiling System (VPS), for the period 2008-2012. This comprehensive, high frequency dataset was utilised to develop a one-dimensional model of the vertical transport and mixing processes occurring along the water column. Multivariate analysis revealed that air temperature and rain forecasts enabled a reliable prediction of the strength of the lake stratification. Vertical diffusion is the main process driving vertical mixing, particularly during winter circulation. However, a high reservoir volume and warm winters can limit the degree of winter mixing, causing only partial circulation to occur, as was the case in 2013. This research study provides a comprehensive approach for understanding and predicting mixing processes for similar lakes, whenever high-frequency data are available from VPS or other autonomous water monitoring systems.