Effect of Geometry on Classification of Flood Flow Source in Naplarood Forest Watershed of Mazandaran Province

Lack of studies in forest Watersheds due to the hydrometric stations absence always causes many problems for managers. The Naplarrood watershed, which has a permanent flow throughout the year and includes many villages downstream, can be the basis for the development of the region in the future with principled and scientific planning. In this research, it is tried to extract some of its important features by geometric analysis of Naplarrood Watershed. Therefore, in this study, 12 effective physiographic factors were used in the field of flood current origin. These factors include river channel bed slope, roundness coefficient, compaction coefficient, Horton coefficient, elongation coefficient, equivalent rectangle length, equivalent rectangle width, slope percentage, slope aspect, branch ratio, drainage density and time of concentration. Then, in order to determine the source of flood flow, all effective factors were rated and weighed based on the used data. Then, flood flow was prioritized using single parameter sensitivity analysis method, as the effective factors in the source. According to the results of sensitivity analysis, three factors of river slope bed, slope percentage and drainage density with weights of 7.42, 6.72 and 6.64 were identified as three important factors in the source of flood flow. Among the effective factors, three factors of drainage density, equivalent rectangle width and branching ratio had a higher optimal weight than the initial weight assigned to them, which shows the importance of these three factors in the origin of flood flow in forest basins.