Mehdi Vafakhah; Mostafa Zabihi Silabi; Sedigheh Modarresi Tabatabaei; Hossein Sarvi Sadrabad; Arezoo Shafiei Bafti; Negin Ghaderi Dehkordi; Mohammadreza Riahi; Seid Saeid Ghiasi
Abstract
Extended abstractIntroductionInvestigating the climatic condition over watersheds has a decisive role in water resource management planning. Meanwhile, changes in temperature and precipitation have a great effect on the discharge of rivers, soil erosion, and fluctuations in the level of ground water, ...
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Extended abstractIntroductionInvestigating the climatic condition over watersheds has a decisive role in water resource management planning. Meanwhile, changes in temperature and precipitation have a great effect on the discharge of rivers, soil erosion, and fluctuations in the level of ground water, and the occurrence of floods. It is very necessary to carry out research related to climate change in order to prepare as much as possible to deal with the harmful costs caused by this change. The review of the studies conducted in Iran also shows that the scale of the study is in most cases at the local level and the study of the mean annual discharge trend and its magnitude has not been studied especially over Iran country. Therefore, the current research was planned with the aim of determining the mean annual discharge trend and magnitude over Iran. Materials and methodsIn the present study, the trend of mean annual discharge in Iran was determined by considering the effect of dams using Mann-Kendall and Sen’s slope methods. First, the statistics of all the hydrometric stations located in the Iran six major drainage watersheds were obtained from Iran Water Resources Management Company. Finally, 139 hydrometric stations with a statistical period of 17 to 65 years were selected in this study. The statistics of these stations were compared with the data available in nearby stations and suspicious values were also controlled. The homogeneity of the data and reconstructing the missing data was carried out using the run test and linear regression through the station with the highest correlation coefficient for each station with incomplete station, respectively. In the next step, non-parametric Mann-Kendall and Sen’s slope estimator tests were carried out within XLSTAT software in order to evaluate the trend and its magnitude analyses. After determining the trend of the study hydrometric stations, the spatial distribution map of the mean annual discharge trend in Iran six major drainage watersheds were prepared within Arc/GIS 10.2 software. Results and discussionThe results showed that 14 hydrometric stations were affected by the dam. However, in the hydrometric stations without dam, 84, six and 35 hydrometric stations have a decreasing trend (60%), an increasing trend (5%), and no trend at the 95% confidence level, respectively. Examining the trend of the time series of mean annual discharge in each of Iran six major drainage watersheds also showed that 80% of the study stations in the Persian Gulf and Oman Sea watershed have a decreasing trend, while no trend were detected in 20%, 10% and 9% of the total study stations in the Caspian Sea, the Central Plateau, and the Persian Gulf and Oman Sea watersheds, respectively as well as all the stations of the eastern watershed (Hammon). In the meantime, all study hydrometric stations in Urmia Lake and Sarakhs watersheds and 68% of the study hydrometric stations in the Caspian Sea watershed have a decreasing trend. ConclusionThe results obtained from this research showed that the decreasing trend was detected in most of the hydrometric stations (84 hydrometric stations). Therefore, the decreasing trend of hydrometric stations in Iran can be related to the decrease in rainfall, increase in temperature and the emergence of excruciating droughts caused by climate changes and also human interference, including the excessive increase in the construction of dams and the change of unprincipled land use. However, one of the limitations of the current research is not taking into account climate changes and land use changes and determining the contribution of each of the mentioned factors in the decreasing and increasing trend of the mentioned stations. The results of the present research can be very useful and important for water planners and politicians in order to manage water resources.
Soghra Malekpurlarki; Zohre Khorsandi kouhanstani; Mohammad Faraji
Abstract
Conservation and utilization of water resources are principles of sustainable development of each country. Surface waters or rivers are one of the most important water resources which have important role in supplying water demands in different sectors such as agriculture, industry, drinking water and ...
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Conservation and utilization of water resources are principles of sustainable development of each country. Surface waters or rivers are one of the most important water resources which have important role in supplying water demands in different sectors such as agriculture, industry, drinking water and energy. Shavoor River which is one of the effective rivers in Shoosh City is important due to its quality in water urban and agricultural usages. Land use and its changes have important effects on river water quality. In this research, the effect of land use change is investigated in water quality of Shavoor River in 1985-2015. For this reason, land use maps of 1985 and 2015 were prepared by satellite imageries and land use changes were investigated. Results showed an increase in residential and agricultural lands and a reduction in rangelands and forests. Also, the changing trend of water quality factors in Shavoor River was studied with Mann-Kendall test and graphs. Results demonstrated that the changes overall trend of Hco3, Cl, TDS, EC, Ca, Mg and So4 were increasing in the period. According to meaningful changes of parameters, it can be concluded that the increase in residential and agricultural lands and reduction in rangelands and forests cause the water quality of Shavoor River in the study period.
Mokhtar Karami; Rasol Sarvestan; Reza Sabouri
Abstract
The purpose of this study was to investigate the effect of climate change on the monthly discharge of Karoon Catchment as the largest basin in the country. In this study, five hydrometric stations (Bamdgeh, Telezang, Gharmaleh, Gotvand and Dezful) and three synoptic stations (Ahwaz, Dezful and Masjed ...
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The purpose of this study was to investigate the effect of climate change on the monthly discharge of Karoon Catchment as the largest basin in the country. In this study, five hydrometric stations (Bamdgeh, Telezang, Gharmaleh, Gotvand and Dezful) and three synoptic stations (Ahwaz, Dezful and Masjed Soleiman) were considered. Using the SDSM software, NCEP data and large-scale data from the general circulation model (HadCM3 for temperature and CgCM3 for water discharge) were scaled parameters under two climate scenarios A1B and A2 in the Karun Basin. Then, the climate change data and the output of the microscale model were applied to the SPSS 19 and Minitab 17 to predict the significance of water discharge for future climate courses (2020-2070) be simulated. Results of climate change analysis showed that under different scenarios, monthly air temperature in the scenario A1B increases by 1.60°C and in the scenario A2 1.58°C, but the average annual rate of stations in the scenario A1B is 19.82 m S-1 in size and 16.27 m S-1 in the A2 scenario. The modified Kendall and age tests were used to identify seasonal and semi-annual seasonal time series trends. Results also showed that under climate scenarios of discharge in spring and first half of the year, there was no significant trend at 95% of confidence, but in other seasons of the second half of the year, there was a significant decrease.
Razieh Saboohi; Hossein Barani; Morteza Khodagholi; Ahmad Abedi Sarvestani; Asghar Tahmasebi
Abstract
Climate change is one of the most important phenomena in recent years have been affected on natural resources and especially the communities whose livelihoods in relation to natural resources, as well as prediction of climate parameters in order to achieve future changes and regard to adaptations to ...
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Climate change is one of the most important phenomena in recent years have been affected on natural resources and especially the communities whose livelihoods in relation to natural resources, as well as prediction of climate parameters in order to achieve future changes and regard to adaptations to deal with climate change is interest of researchers. Therefore, in this study with purpose of previous trend analysis and prediction of precipitation, mean minimum and maximum temperature were used non-parametric Mann-Kendall test and General Circulation Models, HadCM3, respectively. For this purpose, the output data of HadCM3 with three scenarios A1B, A2 and B1 by LARS-WG model were downscale in Semirom region. The results showed that temperature parameters (mean temperature, mean minimum and mean maximum temperature) had increased trend in winter, autumn seasons and annual scale in six studied stations and temperature parameters showed different trend in spring and summer seasons and the annual precipitation is showed negative trend in most of the stations. Also, the results of minimum temperature prediction showed that minimum temperature will generally increase with three scenarios during 21 century and the largest increase in mean minimum temperature compared to the current period is observed in November with more than 0.8 °C increase. The maximum temperature prediction represents a change in the maximum temperature threshold and warming this century in all months of the year, except January and precipitation will increase in all months except June and September using all three scenarios.
Amin Salehpour Jam; Mahmoudreza Tabatabaei; Amir Sarreshtehdari; Jamal Mosaffaie
Abstract
Investigation of drought event has a great importance in the natural resources management and planning water resources management. In this research, the drought characteristics in the selected synoptic stations in northwest of Iran, including Ardebil, Khoy, Oroomieh, Tabriz, Zanjan, Sanandaj and Saghez ...
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Investigation of drought event has a great importance in the natural resources management and planning water resources management. In this research, the drought characteristics in the selected synoptic stations in northwest of Iran, including Ardebil, Khoy, Oroomieh, Tabriz, Zanjan, Sanandaj and Saghez were investigated using the Deciles Index. First, after rebuilding monthly missing data in the period of 1977-2014, time series of precipitation in each station normalized using Box-Cox Transformation. Then, the Deciles Index in different time scales of monthly, seasonal and yearly was calculated based on the normalized monthly precipitation of stations in the period of 1977-2014 by MATLAB and DIP softwares. Then, the drought characteristics, including intensity, duration and frequency were calculated in each synoptic station. In this research, to find the trend of precipitation in the 38 years, 1977-2014, First, trends of the selected stations were determined using Mann-Kendall trend test at the different time scales of the 19 year period, 1977-1995, then compared with trend of the 38 years and finally, determined the changes of the mean precipitation values in two subsequent periods, 1977-1995 and 1996-2014. Obtained results show that the mean annual precipitation at the all stations was decreased in the second period than base period. The results also show that the drought occurrence with different intensity, duration and frequency occurred in selected synoptic stations in northwest of Iran. The results also indicate that there is the decreasing trend of precipitation at the synoptic stations of Saghez and Sanandaj in yearly time scales. Although the stations of Saghez and Zanjan have no trend in the period of 1977-1995, they have decreasing and increasing trends in some time scales in the period of 1977-2014.
