Strategic assessment of sustainable agricultural development potential for Mitchell, Flinders, and Gilbert catchments

The potential commercial viability of irrigated agricultural land use in the Mitchell, Flinders, and Gilbert catchments has been previously investigated as part of the Northern Australia Water Resource Assessment (NAWRA) and the Flinders and Gilbert Agricultural Resource Assessment (FGARA). This report adds to the wealth of previous work through the consideration of economic viability (including the region’s competitive advantages and supply chains) in conjunction with additional factors relating to the cultural, social, climate, and ecological impacts of potential irrigation development in the region. This provides a more holistic picture of the potential of the region for development that is sustainable in the longer-term. This has been undertaken through research and consultation, a series of targeted technical analyses (e.g. GIS analysis and economic modelling) assessing both opportunities and constraints. Opportunities and constraints were then assessed through a multi-criteria analysis (MCA) approach to identify the areas where development is more likely to be sustainable and viable in the longer-term.
The region has ecologically significant wetlands at the Mitchell, Flinders, and Gilbert River mouths fed through river flows. River flows provide connectivity and supply nutrients that support estuarine and marine environments. The commercial fishing industry is reliant on these freshwater flows into estuarine systems to maintain and support fish stocks.
The region also has large areas of protected vegetation (e.g. national parks, conservation parks, and nature refuges), limiting areas that are suited to crop production. The soils in the region are often ill suited to cropping and provide a further constraint. However, the largest constraint for irrigated crop production in the region is related to climate and climate change. High temperatures and associated heat stress limit the number of crops that may be grown. Climate change is predicted to increase temperatures and potentially rainfall, impacting potential crop production. The higher temperatures are predicted to further increase heat stress in crops, reducing potential yields below the breakeven amount. The seasonality and inter-annual variability in streamflow presents an additional issue for irrigation, requiring sizeable storages in order to reliably meet crops water demands. Permanent plantings or high-value horticulture are therefore unlikely to be feasible unless reliability can be ensured or supplemented through groundwater reserves.
There are strong community and cultural links to the rivers in each catchment, communities are strongly connected to Country with rivers used for sustenance. Community involvement in any proposed irrigation development is recommended to ensure community, cultural and social values linked to the river systems are considered in any proposed development.