Assessment of water sensitive urban design management scenarios to manage the long-term impacts of developments on a coastal saltwater lake

An assessment of water sensitive urban design (WSUD) management has been conducted on the impacts of developments on a coastal lake in New South Wales. Proposed developments within the area are required to manage stormwater quantity and quality. A whole of catchment model was developed in 2CSalt to provide inputs of total catchment loads and flows to receiving water quality and ecological response models. The WSUD management scenarios were investigated using MUSIC, and the outcomes integrated back into 2CSalt. Run-off estimates from 2CSalt were derived from a regional calibration of streamflow data. The modelled streamflows from 2CSalt and measured water quality data were used to build pre-development models in MUSIC. The predevelopment models were used as a baseline and compared with the proposed development using generic management techniques based on the local Development Control Plan to control stormwater quality and quantity. The results of this assessment shows that if between 10% and 80% of the development area is designed to control stormwater, there is minimal increase in pollutant loads to the lake in the vicinity of the stormwater outlet. The results will be used by the local council for assessment of stormwater management strategies.