Using satellites to monitor water quality in the coastal zone is currently limited due to suspended sediment and carbon making waters optically complex. For NSW, these parameters peak when extreme events such as East Coast Lows deliver plumes of freshwater to the coast. In 2022, one event delivered ~4-times the annual rainfall in 1-month generating plumes 10’s of km wide and persisting for weeks to months. With increasing events in the future, an increase in impacts on infrastructure, coastal towns, and their communities is also expected.
Initiated in 2021, our Estuarine Outflows Project seeks to fill knowledge gaps on the effects of estuarine plumes on the open coast. With CSIRO, in-water sampling of 9 estuaries commenced in 2022 to develop optical libraries and new algorithms to improve the utility of satellite-remote-sensing as a water-quality mapping tool. Results indicated that optical properties (SIOP) vary most significantly across the river to ocean continuum followed by ‘system’ and then ‘season’. Timeseries analyses have been used to develop a climatology and explore regional variability over 20 years. For our largest estuaries, pixel drills have indicated a relative increase in sediment loads in recent years, likely associated with increased wet conditions.