The Sydney Catchment Authority has been using the Aquatic Real-time Management System (ARMS) as its primary reservoir Decision Support System since 2002. The system is an integral part of SCA’s operations. Hydronumerics provides ongoing maintenance, support and further development of the system through technical advice, data analysis, software development, model calibration and validation, staff training and critical incident response. SCA continues to be a key partner in the development of ARMS and the ongoing relationship between SCA and Hydronumerics ensures that ARMS will remain a premier reservoir management tool