Morphometric Analysis of Landslides of the Ekbatan Dam Watershed and Estimation of their Sediments

The watershed area of Ekbatan dam with an area equal to 22155 ha has located in the northern front of Alvand mountainous in Hamadan province and in a distance of 10 km from Hamadan. In this area landslides have a very specific morphological role and have caused the bareness of the skirts. According to the field examinations and air photography seven cases of land slides have been registered which had specific dispersion in the region. Examinations show that most of the landslides are shallow and over the surface. Collection of surface sediments mostly of sands and gravels in some regions specially depositing pits which are suitable places for the creation of slides. Increase in the stress and increase in the cut stability under different factors cause increasing cuts and land slides in the said pits. Quantity analysis of the slides through morpho metric indicators such as depth indicator, expansion, narrowness, displacement etc. are the representatives of surface slides. Almost all of the landslides in the region are in equilibrium which show the main part of the stable materials from the first site. The increased amount of D/L ratio represents the side expansion and the width change shape of the materials and the estimation of L/D, W/D, and L/W show the direct effect of the slope in creation of landslides. Results showed that changes in the length of slides have been severe and it is more severe in case of length change which with characteristic represents a surface equal to 26668.76 2m and a volume equal to 60517.7 3m, which shows a surface equal or more that 44 cm. In the level of the region they are erupted through the landslides. Therefore slides have an important role in displacement of the materials in the skirts and creating stability and also by creating sediment and leaving it to the rivers of dam region causes the transition and gathering of sediments in the dam and reduction of the Ekbatan dams life.