Geographical Research

Meanders are among the important characteristics of some rivers that flow in semi-arid regions. Swift displacement along the river''s flow، change in the location of the central ridge and bank erosion leateral erosion are resulted from making meander in the river''s flow. Meanders in river courses on North East slopes of Sahand (Located in 46˚ 43́ to 47˚ 15́ E and from 36˚ 05́́́ to 37˚ 20́ N) are very typical. These meanders and their movements are the main cause of lateral erosion and result in the collapse of materials into flood plains and also the creation of these geomorphological-hydrological phenomena and ultimately result in the increase of sediment load in rivers. The intensity of lateral erosion and middle erosion in flood plains is so high that lateral and medial trees are not obstacle against erosion.This article intends to study the meander''s characteristics and the time of movement، by using Δt ،S،R/W… indices.The results of this study suggest that the rate of sinuosity in river courses and also the rate of movements during this time is high and because of the high rate of these lateral movement، the risk of erosion along the middle of the bank is high .