Rahim kazemi; Bagher Ghermezcheshmeh; Reza Bayat
Abstract
IntroductionResearch on low flow is important, not only from a fundamental point of view but also in terms of sustainable water resource management. Optimum water resources management is one of the most crucial challenges of the 21st century, and due to population growth and climate change, water supply ...
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IntroductionResearch on low flow is important, not only from a fundamental point of view but also in terms of sustainable water resource management. Optimum water resources management is one of the most crucial challenges of the 21st century, and due to population growth and climate change, water supply in the future will probably depend on sustainable water sources. The World Meteorological Organization (WMO) introduces low flow as a flow of rivers that continues during the dry period of the climate. Low flow is affected by climate changes, topography, geology, soil, and human activities. The geographical location and climatic conditions of Iran cause a lack of rainfall and water scarcity. Therefore, the recognition and analysis of sustainable water resources is the main component in the surface water resources management of Iran. This research has been done with the aim of investigating the characteristics of scientific publications regarding low flow research in Iran and the world and providing a perspective of the current situation and direction of future research.Materials and methodsThe data relating to low flow research in environmental; agricultural and biological sciences were retrieved from the Science direct database in the period 1999 to 2022 and SCImago Journal Rank indicator (SJR) from https://www.scimagojr.com as well as scientific information database of Jihad Daneshgahi (SID) and data from Iranian Research Institute for Information Science and Technology (IranDoc). A total of 22875 publications were obtained and with following aspects analysed intensively:(1) Distribution of international low flow-related publications (2) low flow-related publications from Iran; (2) distribution of subject categories; (3) core journals; (4) distribution of Iranian articles related to low flow; (5) frequency of low flow-related articles in Middle East and countries around Iran; (6) research trends. Bibliometric techniques, including citation analysis, five-year impact factor, JCR classification, coverage period and h-index were used to evaluate and interpretation of the results.Results and discussionThe results showed that the general trend of global scientific publications in low-flow research was with a positive slope and a growth rate of 1.52%. Also, the trend of international publications from Iran had a positive slope with a 0.94 coefficient of determination and a growth rate of 1.60%. The results of the subject classification of publications at the global level showed that most publications with 85.75% belong to research papers and the least amount to conference papers and editorials. International papers originating from Iran were of the first order of importance to publications with 90.04%, which has a larger share of the total papers than global papers. The results of the analysis of the most important keywords related to low flow showed that more than 72% of the titles of papers and theses were assigned to "base flow" and "flow duration curve (FDC) keywords ".ConclusionsThis research is a systematic bibliographic analysis of texts related to low flow research publication. By summarizing and analysing the growth curve of publications, it can be concluded that the total number of international publications related to low flow research corresponds to the theoretical fitting line and shows the proportionality of the potential of low flow research in the world with the actual amount. The general result of the analysis of international publications from Iran shows a high potential for low flow research in Iran and indicates a change in the attention of the Iranian scientific community to the publication of articles on the topic of low flow at the international level.
Bagher Ghermezcheshmeh; Rahim Kazemi; Mojtaba Nassaji
Abstract
Recognizing and analyzing the behavior of low flow indices is a prerequisite for water resource management and cropping pattern planning in arid and semi-arid regions. The purpose of this study was to analyze low flow in order to provide regional relations and identifying vulnerable areas. In this study, ...
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Recognizing and analyzing the behavior of low flow indices is a prerequisite for water resource management and cropping pattern planning in arid and semi-arid regions. The purpose of this study was to analyze low flow in order to provide regional relations and identifying vulnerable areas. In this study, 26 stations with a common statistical period were selected by examining the daily stream flow data of hydrometric stations in Karkheh Basin. The daily stream flow time series was prepared for each year. Then, three, five, seven, 10, 15, 30 and 60 days low flow and average annual discharge were extracted for each year and each station. A new index was defined as the "low flow index". Then the trend detection of low flow index and its regional analysis was performed. Single and multiple regression between independent parameters of height, area, slope, distance to the outlet and related low flow indices extracted and results were analyzed. The accuracy of simulation was also estimated through the coefficient of determination. The results showed that by increasing the distance from the outlet of Karkheh basin upwards, the trend of the index was higher and in the branches, the obtained index was less than the downstream. This indicates that the branches were more vulnerable and should be focused on better water resources management in the branches.
Aboalhasan Fathabadi; Vahid Anamoradi
Abstract
In hydrological models, in order to better model the runoff process, it is necessary to calibrate the model using observational data. In the process of calibration of hydrological models, in addition to the quality of observation data and the optimization algorithm, the objective function also affects ...
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In hydrological models, in order to better model the runoff process, it is necessary to calibrate the model using observational data. In the process of calibration of hydrological models, in addition to the quality of observation data and the optimization algorithm, the objective function also affects the efficiency of the model. In most studies, statistical criteria such as NSE and RMSE are used as objective functions in the calibration process of hydrological models. Given the structure of the model and the relationships used in each of the evaluation criteria, each of them has good performance in simulating a part of the hydrograph. One of the important parameters of each basin, which is a kind of basin reaction indicator for different discharge values, is the Flow Continuity Curve (FDC). In this study, the efficiency of objective functions based on flow continuity curve and statistical objective functions in optimizing the parameters of the HBV hydrological model in Ziyarat Watershed of Golestan Province was investigated and compared. After introducing input data to model using DDS algorithm, model was calibrated 100 times for each objective function. When model was calibrated, using optimized parameter sets model output for calibration and validation period was obtained. Results showed that criteria such as NSE and KGE have better performance in predicting high flows, criteria such as RMSE and AME predicted moderate flow discharge better and criteria based on FDC had better performance in predicting low flows. In prediction different parts of hydrograph FDC objective function has the best performance, RMSE and MAE were in sound order and NSE and KGE did not have suitable performance.
Ali Nasiri khiavi; Raoof Mostafazadeh; Abazar Esmali Ouri; Omid Ghafarzadeh; Mohamad Golshan
Abstract
The hydrological regime of a river is the main influencing factor on the dynamics of river ecosystem and damming operations have a significant impact on river flow discharge. Therefore, the main objective of this research was to investigate the combined effects of changing climate variables and ...
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The hydrological regime of a river is the main influencing factor on the dynamics of river ecosystem and damming operations have a significant impact on river flow discharge. Therefore, the main objective of this research was to investigate the combined effects of changing climate variables and the Yamchi Dam construction on the discharge flow of the Balkhlu-Chai River in Ardebil using IHA Software 7.1 during the pre and after dam construction period (1973-2003) and (2004-2014). Toward this, the trend in the amounts of precipitation, temperature and evapotranspiration variables were evaluated using MAKESENS software. Then, the changes to 33 hydrological parameters and Range of Variability Approach (RVA) were firstly estimated. Subsequently, changes in the parameters of the flow rate in the periods before and after dam construction were investigated in the magnitude, duration, timing, frequency and rate of change categories. According to the results of trend analysis the precipitation had a significant decreasing trend, while, the temperature has been increased during the available time period. Based on the results, about 92% of the minimum flow discharge was attributed to that after the dam construction, while 25% of the maximum discharge belongs to this period, which indicates a decrease in the magnitude of discharge flow due to the dam construction and decreasing trend of rainfall. Also, the number of high flow pulses during the period of before dam construction was 38% higher than the period of after dam construction, while the number of low pulses in the period after dam construction was reduced by 60.7% compared to the period pre-dam construction. The value of Rise Rate index in the after-dam construction period is 0.11, but in the period before the dam construction is 0.3, which indicates a notable decrease in the mentioned indicator. Generally, based on the Magnitude group parameters, it can be concluded that the average amount of river flow during the period after the construction of the dam decreased by 52% compared with the period before the dam construction which lead to considerable environmental issue regarding the river ecosystem and flow condition. It should be noted that the variation in the hydrologic indicators is mainly influenced by the dam construction and also the change of climate variables has also been influential in this regard, and the separation of affecting factors need to be considered in further studies.
