Development of the formulas for estimating the travel time of rainwater slope runoff and channel flow for the anthropogenic territories of small catchment basins

Abstract

The article presents developed formulas for estimating the travel time of rainwater slope runoff and channel flow based on a unified schematization of mixed catchment basins with wide anthropogenic territories together with diversion channels. The estimation of common travel time for the rainwater overland flow on the adjacent watershed and further along the diversion channel is derived by modeling the catchment basins preserving their natural configurations. The necessary hydrological and hydraulic equations for describing the unsteady rainwater slope runoff and channel flow formation are chosen and proposed taking into consideration the proper factors affecting the flow. When developing a general formula for calculating the preliminary total travel time of the slope and channel flow have been taken into consideration the proper patterns of rainwater runoff on the inclined surfaces and stepped sectors applicable for estimation of the unsteady slope runoff and channel discharge (flow rate) in case of using the differential equations of one-dimensional hydraulics. The developed formula can be used for determining the travel time in predicting rainwater runoff for designing the system of road surface drainage and culverts facilities in mixed catchment basins with terraced paddy fields and other slope areas. Authors have proposed some recommendations and drawn the relevant conclusions.