Hydrogeomorphology
Abazar Esmali Ouri; Arezoo Eshaghzadeh; Shokrollah Asghari; Raoof Mostafazadeh
Abstract
Determining the extent of riverbank erosion and displaying it as a map in a GIS environment is effective in the optimal management of water and soil resources. The aim of the current research is to delineate the riverbank erosion zone from aerial photographs, perform regression modeling, and identify ...
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Determining the extent of riverbank erosion and displaying it as a map in a GIS environment is effective in the optimal management of water and soil resources. The aim of the current research is to delineate the riverbank erosion zone from aerial photographs, perform regression modeling, and identify factors influencing the development of riverbank erosion using various spatial data including physiographic, hydrological, geological, and environmental data in different sections of the Balikhlouchai River in Ardabil Province. Initially, influential parameters in riverbank erosion in the region, including topographic, soil and land factors, hydrology, and land use changes, were calculated. Accordingly, the variables under study were obtained for four time periods: 1955 using aerial photographs, 1980 using TM satellite images, and years 2010 and 2013 using Google Earth images, and the effective extent of riverbank erosion was compared. Subsequently, multivariate regression analysis was performed using independent variables (including topographic, hydrological, soil erodibility, and land factors) and the effective extent of riverbank erosion as the dependent variable, using SPSS software, and suitable models were developed to estimate the amount of different riverbank erosion. Based on the results of regression analysis, environmental parameters such as slope of the river reaches, peak discharge, area under irrigated agriculture, concentration time, pasture coverage, and residential areas played a more significant role in exacerbating riverbank erosion.
Geomorphology
shamsolah Asgari; samad shadfar; MohamadReza Jafari; Kourosh Shirani
Abstract
Sedimentation is one of the most important issues in the watershed. Due to the problems caused by sediment, it is necessary to investigate the relationship between hydrogeomorphic variables affecting sediment production and suspended sediment load in the watershed. The purpose of this study is to model ...
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Sedimentation is one of the most important issues in the watershed. Due to the problems caused by sediment, it is necessary to investigate the relationship between hydrogeomorphic variables affecting sediment production and suspended sediment load in the watershed. The purpose of this study is to model the relationship between suspended sediment loads with hydrogeomorphic variables of the basin and to extract geomorphic features and their relationship with sedimentation in the watershed. By simple random method, two cows and conifers, which include 8 specific sub-basins and are equipped with hydrometric stations, were selected. Statistical multivariate regression method was used to analyze the relationship between geomorphic variables with sedimentation of each sub-basin. The results of the study of the relationship between geomorphic characteristics and sedimentation of sub-basins showed that the amount of sediment produced was positively correlated with slope index, roundness, drainage texture, rainfall, unevenness and basin area and was significant at the level of 0.001. In order to influence the variables on the sedimentation rate of the sub-basins, the principal component analysis and cluster analysis methods were used. The results showed that the three factors of roundness coefficient, slope coefficient and drainage texture coefficient of the basin explain 44.62, 25.22 and 16.74% of the variance of all research variables, respectively. In total, the three final extracted factors were able to explain 87% of the variance of all research variables.
