Application of Simulation-Optimization Approaches to Assess the Effect of Climate and Management Scenarios on in Water Resource System

Optimal allocation of water resources for supply and demand management with respect to climate change effects on water systems is essential. The purpose of this study is to simulate and optimize various components of اAharchay water system under climate change conditions and evaluate different climate and management scenarios.The effect of climate change on weather variables is investigated using the outputs of GCMs under A1B, A2 and B1 scenarios. Results for the period of 2011-2030 showed the decrease of rainfall and an increase of minimum and maximum temperatures for the study area. For estimation of the inflow to the reservoir during 2015-2025 years, the IHACRES model is used. Results for R2 and RMSE criteria were equaling to 0.65 and 1.21 for calibration and 0.56 and 1.4 for validation phases. Moreover, to estimate the water requirement under climate change impacts, evapotranspiration (ET) is calculated by CropWat model. For demand management in agricultural sector, optimization of soil and water allocation was carried out through linear and non-linear programming models (LP, NLP) considering plants’ growth stage and their sensitivity to water stress. Water balance in reservoir was simulated by WEAP under climate change scenarios to allocate water at demand nodes. Considering the climate and management scenarios, the best option was identified by AHP and its associated weights are then calculated. Resalts demonstrated the use of optimal cultivating levels, new irrigation method and reducing per capita drinking water was selected as the best management scenario with the highest values of temporal and spatial reliability.