The lack of scientific knowledge on the flow thresholds and environmental water requirements for specific water sources within the North Coast is a significant limitation in the allocation and implementation of environmental flows. This uncertainty, the limited volume of ECA water and changing NRM platforms has resulted in the limited use of environmental flow allocations and monitoring to date. The aim of this review is to evaluate the existing scientific knowledge of the environmental flow requirements of the regulated water sources; in the Hunter, Chichester and Paterson Rivers, and Glennies Creek in the Hunter-Central Rivers CMA region and parts of the Richmond River in the Northern Rivers CMA region. Outcomes will inform the future development of environmental flow monitoring and research, and decision-making about the management of environmental flows in the North Coast of NSW.