hydro geomorphic factors influence periodic changes in atrak river middle section

river of the most important factors in the cycle of erosion and geomorphologic process and present their studies on the wide are. in this research , the purpose of understanding factors that influence changes geomorphologic middle part of the river bed and atrak river review these changes has been the domain. this area is located between the villages of ghazan ghaye to chat in golestan province approximate length 150 km. research technique is compared to the river bed changes periodic. main research tools was aerial photos of 1935, images of spot and ikonos satellites years 2001 and 2000 and has set up different maps. furthermore, the control of these changes through detailed field work and position and domain registration changes and adapts their gps devise with geo reference maps and images in arc gis other software’s quantitative analyses using mathematical formula. results and the compare the statistical parameters extracted from this section of the river such as geometry, wavelength, wave factor, the dept and width of river bed. the 35 –year period indicates that the coefficient of sinusoidal river 1.5 to 1.3 and decreasing wavelength and radius of the tangent meanders also increased. reviews also indicate that hydrological changes, aggregation material bed and coasts, land use changes and development pattern of cultivation, especially rice cultivation in river flood plains most important factors transformer range plan area and morphology studies during recent years.