بهره‌برداري تلفيقي از منابع آب‌ سطحي و زيرزميني تحت تاثير تغيير اقليم و عدم قطعيت با استفاده از كاپولاي فازي، مطالعه موردي: زيرحوضه نجف‌آباد

Water resources sustainability, particularly in response to increasing water deman‎ds in the agricultural, industrial, an‎d domestic sectors, is a fundamental concern in arid an‎d semi-arid regions. In these areas, socio-economic an‎d ecological development is critically dependent on water resources. In recent years, urban expansion, unsustainable planning, an‎d inadequate integrated water resources management have led to an imbalance between supply an‎d deman‎d, resulting in excessive abstraction from both surface an‎d groundwater sources. Under such conditions, the conjunctive use of surface an‎d groundwater resources, approached comprehensively an‎d aligned with economic, social, an‎d environmental considerations, can serve as an efficient strategy for optimal resource management. However, the inherent complexities of human an‎d natural systems, including climate change an‎d pervasive uncertainties, pose significant challenges to water resources management. This dissertation aims to address the conjunctive water resources management in the Najafabad Plain under conditions of uncertainty an‎d climate change by proposing a hybrid simulation-optimization model. To this end, the simulation model, utilizing vine copula an‎d its fuzzy-vine extended version, effectively captures the complex dependencies among hydrological variables under both probabilistic an‎d possibilistic uncertainties. The proposed model was implemented in two sub-regions, Nekouabad-Left an‎d Nekouabad-Right, an‎d its efficiency was eva‎luated over two 13-year periods: a base period (2003-2004 to 2015-2016) an‎d a future period (2025-2026 to 2037-2038). This eva‎luation was conducted under SSP2-4.5 an‎d SSP5-8.5 climate scenarios, using the outputs of thirteen global climate models. Among various vine copula structures, the C-vine structure, by integrating variables (ΔH, T₋₁, T, GW₋₁, GW, SW, Pr(, demonstrated the best performance in simulating groundwater level fluctuations. A comparison with previous regional models affirms the accuracy an‎d applicability of this approach. To account for possibilistic uncertainty, the model outputs were expressed as fuzzy sets, utilizing trapezoidal fuzzy numbers an‎d α-cuts. Both the fuzzy an‎d crisp outputs of the simulation model were integrated into a bi-objective optimization framework, targeting aquifer sustainability an‎d enhanced agricultural water productivity, an‎d solved using the f-MOPSO algorithm. Base period results revealed that through conjunctive use, groundwater abstraction in Nekouabad-Right an‎d Left regions decreased by approximately 59% an‎d 58%, respectively, indicating improved aquifer sustainability while maintaining productivity. The application of the fuzzy model enhanced the reliability of the results by providing probable ranges for variables such as groundwater level drawdown, productivity, an‎d resource allocation, rather than single point values. Furthermore, the management model determined an optimal adjustment coefficient for controlling groundwater abstraction. Future period results indicate that despite the effectiveness of the conjunctive use model, under the influence of climate change, decreased precipitation, an‎d increased temperature, reliance on groundwater resources will intensify, an‎d groundwater level fluctuations will become more pronounced. Additionally, the projected decline in water productivity in future scenarios further highlights the negative impacts of climate change on agricultural production. The findings of this research demonstrate that integrating a multi-objective optimization model with the vine copula framework an‎d its fuzzy-vine version offers an efficient tool for analyzing an‎d informing decisions in conjunctive water resources management under uncertainty an‎d climate change. It can, therefore, effectively contribute to formulating sustainable strategies for the utilization of both surface an‎d groundwater resources.

حميدرضا صفوي

محمدحسين گل‌محمدي , رسول ميرعباسي نجف آبادي

اميد بزرگ حداد , رضا كراچيان , رامتين معيني , مسعود طاهريون