Regulation of flow in river systems, and use of water for consumptive and economic purposes, has led to detrimental effects on riverine, wetland and floodplain environments worldwide. Policies to return water to the environment focus on minimizing these effects, and balancing environmental and economic objectives, but the practice of delivering environmental water is in its infancy and managers face numerous challenges in doing this. Environmental managers are required to employ ‘best available science’ to deliver ‘evidence-based’ practice, but anecdotal evidence suggests they may not always make best use of the existing scientific literature. Furthermore, current methods to help define environmental flows rarely consider consumptive uses as part of the same set of calculations, which is necessary to optimise returns for both with the available water allocation. We demonstrate two approaches for managers to consider as ways to improve practice. We present a framework to systematically examine the scientific evidence to identify causal relationships between ecosystem attributes and environmental flow releases, which can improve both the defensibility and effectiveness of environmental allocations. We then present a method to evaluate a spectrum of flow options using ecological-response models incorporated into climate-linked daily hydrology and irrigation river-management models, which represent a system’s gamut of rivers, water storages, operational constraints, water management and consumptive demands. A multi-objective optimization approach concurrently models the eco-hydrology and consumptive allocation systems and provides decision makers with a range of alternative optimal management options that represent the most efficient ways to trade-off economic and environmental management objectives.