ارزیابی تأثیر بندهای اصلاحی بر کاهش دبی اوج سیل حوزه

This research evaluates the effect of watershed management on reduction of peak discharge for two situations before and after implementation of operations in Behshahr-Golugah watershed. The method was based on the results of field surveys and recording physical and spatial characteristics of constructed structures and data analysis. Thus, by drawing the longitudinal profile of waterways with check dams before and after construction, time of concentration and peak flow of flood in two states before and after the construction of structures were estimated by SCS method. The results showed that the greatest change in peak flood discharge is in M sub-basin with a decrease of 1.3% compared to before. The mean comparison test using t-test method showed a significant difference between the slope of waterway (Pvalue=0.024), peak flood discharge (Pvalue=0.019) and amount of concentration time (Pvalue=0.030). It exists from the construction of structures. Also, change in peak flood discharge has a significant relationship at 99% level with change in slope of waterway, but their correlation with the number of check dams is lower than other factors. In addition, mechanical measures in sub-basins don’t have ability to extract and store runoff due to the lack of necessary storage tanks and don’t play a role in controlling flood of basin. Therefore, implementation of stone and mortar structures is somewhat effective in reducing intensity and power of flood destruction, and if the number of structures increases and watershed operations are carried out upstream, effectiveness will be increased and the damages will be significant decreases.