Maryam Daemi; Amirreza Keshtkar; Saeed Bazgeir; Ali Afzali; Omid Kavoosi
Abstract
Hydrological drought is used to show the reduction of surface flows and the drop in the level of underground water reservoirs, lakes, and rivers. The present research was carried out to determine the basic flow index values and to check its efficiency in determining the type of flow regime and regional ...
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Hydrological drought is used to show the reduction of surface flows and the drop in the level of underground water reservoirs, lakes, and rivers. The present research was carried out to determine the basic flow index values and to check its efficiency in determining the type of flow regime and regional analysis of hydrological drought in the Halil-Rood watershed. For this purpose, three homogeneous hydrological drought zones were determined based on the threshold level and cluster analysis, and then the base flow index was calculated on a daily scale using the daily discharge data in 10 hydrometric stations in the homogeneous zones. The results showed that the regional average of the annual base flow index is 0.38 with a standard deviation of 0.193 in the long-term statistical period and the range of the base flow index is 0.12-0.29. Based on the 70th, 80th, and 90th percentiles, the river flow regime was divided into four classes, and it was found that 100% of the watershed sub-basins of the study area had an unstable regime. Also, the results of drought zoning showed that hydrological drought occurred at the threshold level of 70 in the southeast of the region in the area of the Dehroud hydrometric station and in the levels of 80 and 90 in the northwest of the region in the area of Baft and Cheshme-Arus stations. The results of the present research can be used in the assessment of underground water supply, water supply systems, irrigation management, hydrological drought monitoring, and regional models in the estimation of water resource reserves in areas without statistics.
Asghar Kouhpeima; Sadat Feiznia
Abstract
Landslide causes many social and economic losses in many parts of the world every year. These losses can be greatly reduced by using appropriate management measures such as mapping landslide susceptibility mapping in the basin. The aim of this study is landslide susceptibility mapping using Mahalanobis ...
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Landslide causes many social and economic losses in many parts of the world every year. These losses can be greatly reduced by using appropriate management measures such as mapping landslide susceptibility mapping in the basin. The aim of this study is landslide susceptibility mapping using Mahalanobis distance in the Latyan catchment. First, a total of 208 cases of landslides identificated and geo-referenced using geographic information systems based on an interpretation of aerial photographs and extensive field surveys and provided a landslide inventory map. The map of 12 factors, including rainfall, land use, distance to fault, distance from river, distance from road, lithology, altitude, slope, aspect, plan curvature, Peak Ground Acceleration and topographic wetness index as the most important factors in landslides was prepared. Then the correlating each factor and the landslide was examined. Finally landslide susceptibility zoning map was provided based on the Mahalanobis distance in Latyan catchment. To evaluate the results, the ROC and chi-square tests were used. The results show more than 80 % of the catchment located in range of high and very high susceptibility classes and need to suitable management operations. AUC index (area under the curve ROC) for this model is achieved to 0.896 or 89.6% which represent capability and high accuracy. Chi-square test results also reflect the proper separation of landslide susceptibility classes by model.
fatemeh maghsoud; Arash Malekian; Mohsen Mohseni Saravi; Omolbanin Bazrafshan
Elham Meshkati; Hassan Ahmadi; Aliakbar Nazari Samani; M.H Davoodi
Abstract
Landslide occurs inevitably and naturally in many slopes due to sensitive formations, moisture, andother factors. Taleghan watershed is prone to landslide due to the presence of huge Miocene marlmasses. After construction of Taleghan reservoir dam, moisture and ecological condition of theregion changed. ...
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Landslide occurs inevitably and naturally in many slopes due to sensitive formations, moisture, andother factors. Taleghan watershed is prone to landslide due to the presence of huge Miocene marlmasses. After construction of Taleghan reservoir dam, moisture and ecological condition of theregion changed. In this paper, factors impacting upon landslide hazard (slope, aspect, hypsometry,geology, land use, distance to road, distance to lake) were studied and their role and importance onthis phenomenon were verified in a large (maximum distance of 1500 meter from lake) and a small(maximum distance of 450 meter from lake) spatial scale. Thus, GIS maps of the above mentionedparameters were provided using satellite and aerial images and field activities. All maps werecrossed with a resolution of 100m*100m. It was found out that the distance to the lake didn’tinfluence upon landslide in a large spatial scale but it falls effective as the distance to the lakereduces. In fact lake has a local effect and mostly influences at maximum 200 meter distance.
