Management and Conjunctive Use of Surface and Ground Water Resources Using Scenario Development Technique, Case study: Dasht-Afzar in Fars Province

Nowadays, population growth and increasing the level of social welfare have led to increased and unpredictable demand for water resources that may disrupt the water resources availability. Therefore, conjunctive use based on the scenario planning method can increase the reliability of the water resources utilization in the presence of uncertainties. In this study, the outputs of three atmospheric-ocean general circulation models have been used to assess climate change effects on the Dasht-Afzar of Fars province. In this regard, the LARS-WG model has been applied to downscaling climate models under RCP4.5 scenario. Then to select the best scenario for groundwater resources reclamation, the WEAP model has been used to simulate possible and probable integrated management scenarios for the next 5 years. These scenarios were; 1) Continuation of the current condition, 2) Development of irrigation network, 3) Construction of artificial nutrition ponds, 4) Water transfer from Salman Farsi dam to neighboring cities, 5) Consumption management, 6) Construction of Kavar dam upstream Salman Farsi dam, and 7) Simultaneous implementation of scenarios 2 to 4 in the consumption management scenario conditions. Performance criteria as well as fuzzy sustainability index were employed to evaluate each scenario's outputs. The results indicated that climate change could not be considered as the main factor in the downward trend of groundwater level. Also, the only scenario that can stop that trend is a 35% reduction in agricultural consumption. In the consumption management scenario, the construction of the Kavar dam will be allowed to store a maximum of 30% of the average flow rate to the Salman dam. Because otherwise, the resource management problems and costs related to the Salman Farsi dam will be increased.