Water market mechanism as one of the water demand management tools can play an influential role in mitigating the effects of water scarcity. So that, in some groundwater markets, the cap-and-trade policy of water permits has led to economic and environmental benefits under water scarcity conditions. Hence, the present dissertation has dealt with the centralized and decentralized modeling of the groundwater market in a part of the Isfahan-Borkhar plain to eva‎luate the effects of implementing the cap-and-trade policy of water permits. In the centralized modeling framework, groundwater permits for water-selling farms have been capped through a bottom-up capping (BUC) policy. With the development of static and dynamic bargaining models in this policy, the process of negotiating among farms over capping permits strategies has been simulated. Then, using a cooperative game-based centralized optimization model, the sale of capped permits of farms to the industry sector has been simulated, and the benefits of water exchanges between buyers and sellers have been fairly reallocated. Furthermore, the decentralized modeling framework has used the agent-based modeling (ABM) approach to simulate continuous interactions in a complex water market system. The proposed ABM framework has dynamically coupled the three social, economic, and hydrological sub-models. The social sub-model has benefited from the theory of planned behavior under field studies to design psychology-based behaviors of trading agents. Moreover, in continuous interaction with the FlowLogo hydrologic sub-model, the economic sub-model has simulated water trading under a discriminatory double-auction mechanism. The results of the centralized framework revealed that the BUC policy proposes more acceptable capping strategies than the top-down (command-and-control policy) approach because it considers farmsʹ utilities. Simulation of the inter-sectoral water exchanges process showed that although due to production restrictions in the industry sector, the sales volume of irrigation water is relatively low and about 217,000 (m3), however, most industrial units purchase as much water as they want. Moreover, the industry sector facilitates the implementation of inter-sectoral water exchanges by paying an incentive payment of 3,242 (Million Tomans) to water-selling farms where the current net benefits of agriculture and industry sectors have increased by 55% and 27%, respectively. Finally, the set of centralized modeling results clarified that the proposed framework for centralized modeling of the water market can facilitate the implementation of capping strategies and improve the water permits productivity. The results of the decentralized modeling framework showed that water trading patterns (water transactions price and volume) experienced relatively extreme variations in the first years. However, with the adaptation of the agentsʹ bids to the market conditions, they gradually have emerged in a more stable form in the last years. These results reflected that the memory of a human, which includes his/her experiences and feedback from the previous trading stages, plays a fundamental role in forming his/her next bids within the market. Furthermore, updating the psychological factors has increased the agentsʹ intention of participating in the market, and thus, the market competition level (transactions volume and number of participants) over time. The hydro-economic analysis also revealed that the total net benefits of market participants had been increased by an average of 27% per year, and the regionʹs groundwater drawdown has been reduced by 64 (cm).

آزاده احمدي

عليرضا نيكويي

بنفشه زهرايي، مهدي ضرغامي، حميدرضا صفوي