A development pathway to optimise sustainability of water investment and minimise social cost

Traditional development of water and agriculture based on irrigation tends to lead to over-extraction of water from the environment as water use ‘peaks’. The remedy to this behaviour is to re-invest in efficiency improvements and alternative water resources, in effect paying twice for capacity. An alternative is to adopt a different development pathway, utilising both irrigation (blue) water and rainfed soil (green) water to provide a reliable supply. Such conjunctive use means that ‘virtual water’ exported in crops contains less blue water. This means the higher opportunity cost of blue water use can be directed to advantage local populations, especially important when considering non-renewable groundwater resources. The new paradigm avoids ‘peak water’ through sustainable optimisation of available resources.