Reza Chamani; Mehdi Vafakhah; Seyyed hamid reza Sadeghi
Abstract
Today, drought has become one of the hot topics of global concern, but its impact on the provision of services and functional health of watersheds in the face of this natural disaster has been less evaluated. Accordingly, in this study, the effect of drought on the Efin Watershed health has been evaluated ...
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Today, drought has become one of the hot topics of global concern, but its impact on the provision of services and functional health of watersheds in the face of this natural disaster has been less evaluated. Accordingly, in this study, the effect of drought on the Efin Watershed health has been evaluated based on changes in Reliability (Rel), Resilience (Res) and Vulnerability (Vul) indicators in the period 2005-2019. Based on this, the rainfall data of three rain gauge stations were interpolated using Inverse Distance Weighting (IDW) for the watershed and sub-watersheds. Standardized Precipitation Index (SPI) was then determined based on the mean and standard deviation of monthly data and was used to calculate the Rel, Res and Vul indicators. Finally, the overall health status of the watershed was determined by calculating the geometric mean of these indicators. The annual results showed that Efin Watershed in terms of Rel, Res and Vul indicators extends between 0.83-0.92, 0.17-0.33 and 0.24-0.54, respectively. The RelResVul index also has values between 0.37-0.53. The average watershed health indicator in this period was also calculated to be 0.42, which indicates mean watershed health condition. Spatial variations of watershed health also showed that Rel, Res and Vul indicators fluctuated between 0.85-0.86, 0.21-0.24 and 0.76-0.78 in different sub-watersheds. The results of rainfall analysis of the region, indicate that due to the relative stability of rainfall, the impact of human intervention and intensification of watershed health threatening factors, more than ever effect on the current situation and if not addressed will have harmful effects.
Reza Chamani; Seyed Hamidreza Sadeghi; Mehdi Vafakhah; Maryam Naghdi
Abstract
Drought is one of the natural disasters related to climate and one of the most important threats to human survival leading to adverse effects on social, economic, and environmental sustainability. In this study, it has been tried to evaluate the changes in reliability, resilience, and vulnerability of ...
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Drought is one of the natural disasters related to climate and one of the most important threats to human survival leading to adverse effects on social, economic, and environmental sustainability. In this study, it has been tried to evaluate the changes in reliability, resilience, and vulnerability of the Chalous Watershed under the influence of drought in the period of 1982-2017. In this vein, rainfall data of nine stations were interpolated using invers distance squared method to the whole watershed. The SPI drought index was then determined through determining the mean and standard deviation of the data. To calculate Rel, Res and Vul indices, the mean value of SPI Index was used. By calculating the geometric mean value of these indicators, the general health status of the watershed was determined and quantified. The results showed that the SPI Index in this period varied between -1.43 and 2.25. Drought index had a similar pattern to that of rainfall with an increasing trend at the end of the period. The watershed health assessment also showed that the indicators of reliability, resilience, and vulnerability were found 0.5, from 0.23 to 0.62 and from 0.06 to 1, respectively. The geometric mean of these indices was also ranged between 0.19 and 0.58. The overall health condition of the Chalous Watershed based on the dynamics of drought index with a mean index of 0.45 was classified as “moderate”. The findings of the current research will play an important role in explaining the methods of adaptive management of the watershed.
Reza Chamani; Mahmood Azari; Sven Kralisch
Abstract
The hydrological effects of climate change are a great challenge for water resources management. Determining climate change impacts on hydrological processes is a prerequisite for adaptation strategies to climate change; which in turn is necessary for water scarcity crisis in future. The purpose of this ...
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The hydrological effects of climate change are a great challenge for water resources management. Determining climate change impacts on hydrological processes is a prerequisite for adaptation strategies to climate change; which in turn is necessary for water scarcity crisis in future. The purpose of this research is to determine climate change impacts on hydrological regime of the Chehelchay watershed in Golestan province. J2000 distributed process based model was used for simulation of the hydrological process. Output results of seven climate models including CanESM2, CCSM, BBC-CSM1.1, CESM1-BG, CESM1-CAM5, ICHEC- EC-EART and MPI-M-MPI-ESM-LR for two Representative Concentration Pathways scenarios (RCP 4.5 and RCP 8.5) for 2071-2100 were used for climate change impact analysis. Study results revealed that the maximum temperature for RCP 4.5 and RCP 8.5 in 2071-2100 will increase by 2.6 and 4.7 °C and the minimum temperature will increase by 2.4 and 4.5 °C respectively by the end of the 21st century. In addition, precipitation for RCP 4.5 will increase by 0.6 percent and for RCP 8.5 will decrease by 0.6 percent. Modeling results show these will lead to significant changes in the hydrological regime. In particular, evapotranspiration will increase by 9.6 and 16.7 percent and stream flow will decrease by 4.2 and 3.2 percent. The results of the hydrological changes will cause a decrease in stream flow in April –June and for RCP 8.5 will be continued till October.
