Geomorphology
Naimeh Rahimi; Somaiyeh Khaleghi; Alireza Salehipour Milani
Abstract
In the east of Jask City, four severe floods with high discharge occurred in the Sadij River between 2009 and 2019. This research aims to evaluate the morphological changes of the Sadij River due to the occurrence of floods over a period of 11 years and in the four significant floods during 2009, 2014, ...
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In the east of Jask City, four severe floods with high discharge occurred in the Sadij River between 2009 and 2019. This research aims to evaluate the morphological changes of the Sadij River due to the occurrence of floods over a period of 11 years and in the four significant floods during 2009, 2014, 2017, and 2019. Geomorphic effects on the river were extracted using Landsat and Google Earth satellite images. GIS10.5 software and the Fluvial Corridor were used to investigate the morphological changes caused by floods in the river. The erosion and sedimentation levels were evaluated with the RNCI model. The results showed that the average width of the channel decreased by about 38 m, and the length of the river increased by about 3510 m in the floods between 2009 and 2019, corresponding to the increase in the curvature coefficient of the river from 1.40 to 1.56. According to the results of RNCI, the flood of 2019 with a discharge of 1167.73 m³ caused the highest amount of erosion compared to the other floods. Among the studied reaches, the most changes in geometrical parameters belonged to reach B
Mojtaba Yamani; Abolghasem Gourabi; Zahra Abedini
Volume 2, Issue 3 , January 2017, , Pages 137-157
Abstract
Rivers are dynamic systems and their space-time characteristics are constantly changing. This change and displacement creates problems in the human and ecological functions and the study of such changes are the main issues in the fluvial geomorphology. In this study, survey morphological changes in one ...
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Rivers are dynamic systems and their space-time characteristics are constantly changing. This change and displacement creates problems in the human and ecological functions and the study of such changes are the main issues in the fluvial geomorphology. In this study, survey morphological changes in one section of the Babolroud (Bobol River) will be examined during the time period of 1334-93 from Babol city to Kardgarkola village within 18/45 km. Using aerial photo from 1334 and 1383 and satellite images Landsat 8, 1393 the path of the river was digitalized in three time periods with Arc GIS software. To determine the type of changes in each of the beaches spatial and temporal interval were studied and the position of the coastline was compared to the previous coastline. Then, for each beach in each period shifts named layer was prepared and its surface was measured. Then for each time interval (period) studied, the spatial interval was specified. The statistical tables were considered for each time interval to provide possible comparisons between the spatial intervals. Finally, changes in the left and right of each interval in each period was compared to the period before. For a detailed analysis, changes in the stream in each of the study periods were considered after determining the thalweg, the fixed line and the taken transects within the interval of 1000 to 1000 meters. Then, in the Arc GIS, after the determining the transects and thalwegs, and creating a polygon, the area of polygon was compared to the previous periods. Finally, through the implementation of existing disputes, thalweg changes in the riverbed, which determined the cause of the change, was found in each transect. The results show that the interval in the regression process has three periods. The second interval depicted the greatest change. The main reason for this fact in the period of change is excessive land use and human intervention.
