The Mitchell River, which flows into the Gulf of Carpentaria supports many important freshwater ecological assets, including wetlands of national significance, sources of traditional Indigenous harvest and commercial and recreational fisheries. There is significant interest in agricultural expansion in Northern Australia, particularly within the Mitchell River catchment. This project aims to improve our understanding of the critical flow needs to sustain freshwater ecosystems in the Mitchell River catchment and the implications of future land and water resource development. Drawing on remote sensing, field experiments and ecological tracer analyses, the project takes a whole of ecosystem approach to this question. Analyses of floodplain inundation and observed river flow have identified at least 50% of the annual area of inundation is due to river flow from upstream rainfall. Field experiments into algal production at inundated wetlands failed to identify consistent patterns of drivers of primary production. However, there were broadly consistent relationships between algal production and turbidity depending on the habitat type with 30% of variation in primary production dependent on these two factors. These results are supporting analyses of the food webs, both floodplain and instream, using essential fatty acid and bulk stable isotope tracers to quantify functional connectivity of the floodplain, as facilitated by flow. Complementing these wholly freshwater results are analyses of fishery caught barramundi that show the total wet season river discharge has a direct bearing on annual growth rates in juveniles. The results of this study will enable decision makers to predict the consequences of water resource development on important flow-dependent assets in the Mitchell River. Such information is vital to enhance policy decisions about water allocation and protect important freshwater and coastal ecological assets if agricultural development does proceed.