Assessment of Watershed Operation and Introduction of an Innovative Method in Determining Flood Control Dams

During the last decades، because of incorrect using of natural resources, the degradation rate of watersheds, soil and water resources have been increasingly grown. Furthermore, while this issue intensifies floods occurring, increases sediment production rate and decreases useful life time of dam reservoirs, it has provided the causes of decreasing the country national investments and products. This research which has been done in Bardeh watershed with 32 square kilometers area in Charmahal province, deals with evaluating of mechanical impact measures on the watershed behavior in decreasing flood and flooding potential. The work method is on the basis of field investigations, results and also recording the physical and spatial characteristics of buildings. In the next stage, using SCS model and simulating the watershed flood, the effect of buildings on the watershed flood and runoff control has been studied. The results show that the buildings with volume about 471 m3 in addition to store runoff and to impact on percolation of runoff flow is also capable of controlling the flood with time period of 25 years. The analysis of output data resulted from SCS model in normal conditions and statistical comparison with simulated flood data along with watershed operations indicates that in 95 percent level there is a meaningful difference among data. Also, using the research results, an equation has been proposed to estimate the required numbers of small dams.