Effective management of water resources is vital for maintaining productive agricultural systems, thriving communities and healthy ecosystems. Water use for multiple objectives, such as agricultural irrigation and environmental outcomes, is increasingly important with declining water availability due to climate change and increasing consumptive demands. Water supply authorities that manage bulk water from dams and weirs are responsible for huge quantities of water within catchment systems. Due to their control over the timing, quantity, and duration of flows from dams into riverine systems, they have significant influence on how riverine systems operate within agroecological systems. This study aims to understand water supply authorities’ decision-making process regarding environmental outcomes for irrigation water in key irrigation regions of Australia. We undertook a qualitative study involving semi-structured interviews with water supply authorities’ officials. We asked them a range of questions regarding what environmental considerations are made, policies and frameworks that drive their decision making and how they might increase ecological outcome of irrigation water. We found that some environmental considerations are made; however, they are under the lens of managing the river to deliver irrigation water. Policies and frameworks must be implemented to increase the ecological benefit of irrigation water.