The estuary environmental flows assessment method (EEFAM) is a standard methodology which can be applied consistently across Victorian estuaries. The primary objective of EEFAM is to define a flow regime to maintain or enhance the ecological health of an estuary. While the method is used to inform Victorian water resource planning processes it could be used in many parts of southern Australia.
The output of EEFAM is a recommended flow regime for estuaries. This recommendation is developed from the known dependence of the estuary’s flora, fauna, biogeochemical and geomorphological features on the flow regime. EEFAM is an evidence-based methodology. This ‘building block’ approach conforms to the asset-based approach of the Victorian Waterway Management Strategy and regional waterway strategies.
EEFAM is based on FLOWS, the Victorian method for determining environmental water requirements in rivers, but refined and expanded to reflect environmental and management issues specific to estuaries. EEFAM and FLOWS can be applied simultaneously to a river and its estuary as part of a whole-of-system approach to environmental flow requirements. EEFAM is also modular, and additional components can be readily incorporated.
The draft method was trialled and refined by applying it to the Werribee and Gellibrand estuaries. The final methodology describes the role of a documented objective setting process that links environmental objectives to flow objectives and recommendations through the use of ecological conceptual models; the use of a multi-disciplinary expert panel and the use of hydrological tools and hydraulic models to support the development of environmental flow recommendations.