The Optimal Dynamic Model of Conjunctive Water Use

抄録

This paper considers dynamic water allocation for the conjunctive use of surface water and groundwater. Conditions that determine temporal and spatial optimization problems are identified. Temporal allocation is governed by the Hotelling rule, which determines the optimal allocation of the initial stock of water for each period. On the other hand, the spatial allocation of water is constrained by the amount of the initial stock of surface water flow into the canal at each period. The optimal allocation of water results in allocating more water in the first period when fixed recharge to groundwater is available in later periods. As a result, the shadow price of water becomes less in later periods, providing incentives for farmers to use more water at the head of the canal. The results suggest that if the irrigation system deteriorates in later periods, the distribution of land rents in favor of head firms may be further intensified.