Conjunctive use of groundwater and surface water in the Burdekin Delta Area

One of the key economic issues faced by the managers of the two water boards in the Burdekin River Delta is the allocation of surface water between immediate use on farm for irrigation and storage in the aquifer for future use. Because of the significance of the interaction between surface water and groundwater and the return flow externalities within the delta, policies on surface water and groundwater need to be determined simultaneously. A model is formulated of the dynamic system of surface water and groundwater in the delta with water demand, groundwater extraction cost and stochastic recharge and surface water availability. The optimal pumping/artificial recharge policies for each state of the joint surface water and groundwater system is derived for the southern part of the delta and this policy is applied over a large number of years to derive the expected development over time of extraction/ artificial recharge and the state of the groundwater system. The implications of the optimal pumping/artificial recharge policy for any review of existing allocations of surface water and groundwater are discussed. [PUBLICATION ABSTRACT]