The Murray–Darling Basin Authority determines the water resource availability scenario-based climate conditions over the previous year (rainfall, runoff and soil moisture) and surface water available in public dams. By comparing these with the historical record we gain a better understanding of the dryness or wetness of catchments across the Basin. The five water resource availability scenarios range from very dry to very wet.
When determining the scenario, we also draw on the Bureau of Meteorology’s seasonal and longer-term forecasts to provide context about potential conditions over the months ahead.
The scenarios help to guide water managers in deciding the kinds of watering activities that will best support the health and condition of water-dependent ecosystems across the Basin. For example, under dry conditions, water for the environment can provide drought refuges – permanent freshwater holes that remain even when the surrounding area is dry, while in wet conditions water for the environment can support waterbird breeding, fish spawning, and new plant growth on floodplains.
Last updated: 30 April 2025