Comprehensive assessment and scenario simulation for the future of the hydrological processes in Dez river basin, Iran (original) (raw)
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Earth Science Informatics, 2021
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This paper aims to summarize in detail the results of the climate models under various scenarios by temporal and spatial analysis in the semi-arid Karkheh Basin (KB) in Iran, which is likely to experience water shortages. The PRECIS and REMO models, under A2, B2 and A1B scenarios, have been chosen as regional climate models (RCMs). These regional climate models indicate an overall warming in future in KB under various scenarios. The increase in temperature in the dry months (June, July and August) is greater than the increase in the wet months (January, February, March and April). In order to perform climate change impact assessment on water resources, the Arc-SWAT 9.3 model was used in the study area. SWAT (Soil and Water Assessment Tool) model results have been obtained using present and future climate data. There is an overall reduction in the water yield (WYLD) over the whole of the KB. The deficit of WYLD is considerable over the months of April to September throughout KB due to the increase in average temperature and decrease in precipitation under various emission scenarios. Statistical properties in box-and-whisker plots have been used to gain further understanding relevant to uncertainty analysis in climate change impacts. Evaluation of uncertainty has shown the highest uncertain condition under B2.
Assessment of climate change impact on surface water: a case study—Karoun River Basin, Iran
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We study and forecast the effects of near-future (NF) land use and climate changes (LUCC) on the hydrological regime (HR) within the Zilbier river basin located in arid and semiarid regions, in the Azerbaijan province in northeast and northwest of Iran in the recent past (2004-2014) and 2030. We used the baseline data (S B) and 13 potential NF scenarios to evaluate the effects of changes in land use, temperature and precipitation, both in isolation and in combined scenarios by application of the Soil and Water Assessment Tool (SWAT). Climate changes (CC) were represented by the delta change approach based on trends for past 3 (1985-2014) or last decade (2005-2014), respectively (low delta change (LDC) and high delta change (HDC)), where the trends of the most recent decade yield a higher delta change when extrapolating to 2030. Similarly, land use changes were derived from trends observed based from satellite imagery and Cellular Automata-Markov model (CAM). In the NF, the results indicated that the climate would universally become warmer and drier under both LDC and HDC and increase the high-consumption land uses such as orchards in the study area, respectively. In 2030, CC tend to effect more conspicuously the HR than LU changes, leading to decrease in the entire hydrological component except evapotranspiration. Surveying the whole array of the simulated scenarios, there were clear and non-linear synergistic effects of the combination of LU and CC scenarios, and taking into account both of these is, therefore, critically important if model results are to be used for decision-making support.