Sharif Digital Repository

Hydrologic analysis in order to design the collection and transmission structures of urban runoff require some time parameters as input that the accuracy of these analysis is directly sensitive to the accuracy of these parameters. Among these parameters, the time of concentration is the most frequently utilized time parameter and numerous equations for estimating the time of concentration in urban watersheds have been proposed. The purpose of this study is to propose some equations to estimate the time of concentration of overland flow in small urban watersheds with pattern similar to arid and semiarid regions and investigate the effect of using LIDs on reducing the surface runoff.... 

The direct impact of rainfall in human life and its fundamental role in water resources management cause the development of methods and algorithms to estimate the rainfall among the researchers. In the past decades the traditional methods were used to measure the amount of rainfall until the advent of Meteorological Satellites has sparked a revolution in this field. Significant temporal and spatial changes of rainfall and the small number of the synoptic stations caused negative impact on the actual distribution of the amount of rainfall in a vast area. The rainfall satellite data were somewhat overcome by existing deficiencies in Synoptic methods by providing a better rainfall distribution...