ESTIMATION OF EROSION AND SEDIMENTATION USING SEDIMENTOLOGICAL DATA AND CALCULATION OF SUSPENDED SEDIMENT LOAD IN GARMSAR WATERSHED

Erosion, sediment transport, sedimentation and water quality are very important issues in watershed management. Based on the initial study, it was found that the three factors of geological materials, slope, and climate are the most important factors in erosion. Therefore, these three factors were examined and combined to create work units. Then, the qualitative sensitivity of the rocks and pre-Quaternary formations was continually determined using the criteria of resistance method and hardness of the rock mass in a field method. Then, several statistical regression models were investigated by discharge classification and temporal separation of data; and by establishing a regression relation between flow discharge and sediment discharge data and its simulation, sedimentation rating curves along with FAO and USBR were presented based on the error least squares method according to statistical analysis methods, and annual long run suspended sediment load values were estimated by combining the proposed models and flow discharge methods such as flow continuity curve, daily mean discharge, and monthly mean discharge. In this regard, the statistics of a 13-year period of Bankooh hydrometric station on the HablehRood River were used. Finally, combination of the classes mean model with the mean daily discharge by FAO method was introduced as a suitable model.