Ali Rajaee; Baharak Motamedvaziri; Aliakbar Nazariye samani; Hasan Ahmadi
Abstract
In this study, 18 variables affecting avalanches have been studied. These variables are related to the conditions: geomorphological and topographic, climatic, snow and also Some activities are related to human factors. In this study, the avalanche risk map was prepared and analyzed using the risk model ...
Read More
In this study, 18 variables affecting avalanches have been studied. These variables are related to the conditions: geomorphological and topographic, climatic, snow and also Some activities are related to human factors. In this study, the avalanche risk map was prepared and analyzed using the risk model (HEV) and the variables affecting the occurrence of avalanches. Avalanche hazard map was prepared using three models: AHP, Garp and MaxEent. Based on three risk factors for avalanches, obstacles in the avalanche route and also sensitivity to avalanches, a risk map was prepared. Comparison of the results with field visits and avalanche occurrence areas and past statistics and information indicate the accuracy of the hazard map with 93.85% accuracy by the AHP method. One of the most important variables in avalanche occurrence in this area is the slope. Then, using two maps of avalanche risk elements and avalanche susceptibility map and avalanche hazard map, snow avalanche risk map has been prepared. The results showed that the avalanche hazard map has a very inherent difference with the avalanche risk map. Areas in the low-hazard category on the avalanche risk map became more important in the avalanche risk map. The most important reason is the existence of endangered elements and the development of residential lands in this area over the past few decades
Aliakbar Nazari Samani; Fatemeh Avazadeh Tavakoli; Hassan Ahmadi; Gholamreza Rahi
Abstract
Gully erosion is one of the most destructive types of channeled water erosion that removes aconsiderable volume of soil as it develops. This type of erosion consists of complex a geomorphicprocess that has been known as an indicator of accelerated soil erosion. In this research theadvancement of 25 headcuts ...
Read More
Gully erosion is one of the most destructive types of channeled water erosion that removes aconsiderable volume of soil as it develops. This type of erosion consists of complex a geomorphicprocess that has been known as an indicator of accelerated soil erosion. In this research theadvancement of 25 headcuts were assessed through digital interpretation of multi-temporal aerialphotos, field observations and GIS data analysis over the two periods of 1967-1995 and 1995-2008.Moreover, the stepwise regression analysis procedure was applied to extract the effective factors ongully head advancement (such as topography, physico-chemical soil attributes and morphology ofgully). The results indicated that the mean of gully head advancement over the periods of 1967-1995,1995-2008 and the mean of two periods were measured 1.36, 1.23 and 1.3 m/y, respectively. Further,regression analysis revealed that headcut's contribution area, distance of gully-head to ridge, height ofgully head cut and SAR are the main factors on gully head advancement. Therefore, distance to ridge,headcut high and presence of plunge pool could use as suitable criteria to distinguish the active gulliesin order to prioritizing the conservation activities.
