Tohid Rahimpour; Shahram Roostaei; Mahsa Nakhostinrouhi
Volume 4, Issue 13 , March 2018, , Pages 1-20
Abstract
Introduction A landslide is a natural phenomenon that often occurs because of falling down or seamless and quick movements of volumes of sediment along the slope. It has such speed and extent that it may influence tens or hundreds of cubic meters of rock and soil together. This phenomenon causes a lot ...
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Introduction A landslide is a natural phenomenon that often occurs because of falling down or seamless and quick movements of volumes of sediment along the slope. It has such speed and extent that it may influence tens or hundreds of cubic meters of rock and soil together. This phenomenon causes a lot of economic damages to forests and their growth, farmlands, gas and power transmission lines, mines, engineering structures, and buildings. One of the best ways to prevent these damages is preparing a landslide hazard map. Methodology The method used for zoning the Sardool Chay Basin is the Analytical Hierarchy Process. This is one of the most comprehensive multi-criteria decision methods, which was first presented in 1980 by Thomas L. Saati. This method is based on weighing each pair of variables with each other. AHP method consists of three main steps including (1) creating an Analytical Hierarchy, (2) comparing pairs of elements in it, and (3) weighing the criteria. The main feature of this method is the use of expert opinions. In AHP,n paired factors are compared with each other and more weight is given to the layer that has the maximum impact on the target set. The paired comparison of a scale, based on1 to 9, for its two components' relative weighing is hierarchical. Discussion In this study, the landslide hazard zonation was used in the Sardool Chaycatchment in order to identify areas with landslide incidence potential. The main factors contributing to the landslide occurrence in this case study consisted of geology, land use, slope, aspect, rainfall, altitude, distance from faults, and distance from stream. Their layers were prepared in ArcGIS software. An Analytical Hierarchy Process in Expert Choice software was used for paired comparisons of criteria and calculation of final weight. The results indicated that the geology criterion, which weighed 0.343, and the slope criterion, which weighed 0.215, had the most influences on landslide occurrence. Conclusion Landslide is one of the most common environmental hazards in mountainous areas of the northwest of Iran. Factors such as slope, rainfall, lithology, and earthquakes can trigger them. One of the best ways to deal with this phenomenon, before the implementation of any project, is the zonation mapping of the area. This study was based on the Sardool Chay catchment, located in Khalkhal, the southern part of Ardabil Province. To this end, 8 factors including geology, land use, slope, aspect, rainfall, altitude, distance from faults, and distance from stream were used. The weighting factors and the Analytical Hierarchy Process (AHP), and the Expert Choice software were used. The results classified the basin into five areas including very high risk of landslides (65 km²), high risk (144 km²), medium risk (202 km²), low risk (142 km²), and very low risk (120 km²). In addition, it indicated that the landslide risk of the Sardool Chay catchment is medium. Comparing the landslide zonation map and points of distribution suggests that the AHP can be a good method of weighing the criteria involved in the happening of the landslide.
Khalil Valizadeh Kamran; Shahram Roostaei; Tohid Rahimpoor; Mahsa Nakhostin Rohee
Volume 3, Issue 6 , January 2017, , Pages 17-32
Abstract
Khalil Valizadeh Kamran[1] Shahram Roostaei[2] Tohid Rahimpoor[3]* Mahsa Nakhostin Rohee [4] Abstract In all of the world and including our country, groundwater is the most important resource for water supply needed. Determination of the quality of water has specific importance ...
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Khalil Valizadeh Kamran[1] Shahram Roostaei[2] Tohid Rahimpoor[3]* Mahsa Nakhostin Rohee [4] Abstract In all of the world and including our country, groundwater is the most important resource for water supply needed. Determination of the quality of water has specific importance in the management of resources and its monitoring should be considered as an important principle in planning. The aim of this research is of the determination of the most appropriate interpolation method for spatial analysis of electric conductivity and sodium absorption ratio changes of groundwater of Shiramin plain located in East Azerbaijan province. The related information are obtained from analysis of the samples involving 30 deep and semi-deep wells based on the sampling of the year 1390 by regional water organization of East Azerbaijan province. The geostatistics methods such as simple, ordinary and discrete Kriging and also CoKriging were used for doing this research. For investigation of the spatial correlation of data, the experimental variograms of each variables and its reciprocal variogram were calculated and plotted. The correlation coefficient of two variables were calculated at 0.93 according to their related variogram. The spherical model was fitted as the most appropriate model for both of the EC and SAR parameters based on the minimum of RSS. The reciprocal estimating method with root mean square error criterion and also correlation coefficient (R) between the observed and estimated values was used for assessment of the reliabality of methods. The results of research showed that because of higher R and lower RMSE, the simple Kriging method was the most appropriate method within the others for preparation of the map of SAR and EC changes. Keywords: Groundwater, Geostatistics, EC, SAR, Shiramin plain. [1]- Associate Professor of Remote Sensing, University of Tabriz, Tabriz, Iran [2]- Professor of Geomorphology, University of Tabriz, Tabriz, Iran. [3]- Master Student of of Remote Sensing, University of Tabriz, Tabriz, Iran (Corresponding Author) Rahimpour1990@gmail.com. [4]- Master Student of Remote Sensing, University of Tabriz, Tabriz, Iran.
