Integrated biophysical and economic modelling framework to assess impacts of alternative groundwater management options

We developed an integrated biophysical and economic modeling framework to assess impact of various groundwater management options on seawater intrusion and waterlogging and ultimate impact on sugarcane profitability in a coastal region of North Queensland, Australia. The modelling framework used the output of a groundwater management flow model (waterlogged and seawater intruded areas) and a crop simulation model (simulated crop yield) and maximised the net revenue in a mathematical programming (optimisation) model. The framework determined the economically optimal level of water use on different soil types and in different management regimes and estimated impact of seawater intrusion and waterlogging on net revenue of growing sugarcane in two neighbouring water board areas (North Burdekin Water Board - NBWB and South Burdekin Water Board - SBWB). In NBWB, the predicted aggregate net revenue was highest ($19.95 million) when groundwater use was also highest (70%) while predicted aggregate net revenue was lowest when groundwater use was also lowest. In SBWB, the predicted aggregate net revenue was highest ($23 million) when groundwater use was relatively low (61%). The predicted aggregate net revenues of all the management options were higher in SBWB than NBWB.