Working with the Government of the Australian Capital Territory, Hydronumerics was commissioned to undertake the design and analysis of in-lake water quality improvement options for Lake Tuggeranong (Australia). A three-dimensional hydrodynamic and water quality model was used to test the efficacy of each proposed intervention in terms of reduction of Blue-Green Algal concentrations, as well as discharge TSS, TN and TP. Forecast phytoplankton growth and both in-lake and downstream amenity were also modelled for a range of Water Sensitive Urban Design (WSUD) portfolios under the government’s AUD $85 Million Basin Priority Project. Hydronumerics’ work was used to estimate the reduction in shut down days and downstream water quality for the nationally important Lake Burley Griffin as well as Lake Tuggeranong, and the downstream Murrumbidgee River.