The Overland Flow Resistance along Slope Distance in an Experimental Flume

A series of overland flow experiments were conducted by changing slope degree including 15 degrees, 20 degrees and 25 degrees on the smooth and adhering sand slope, the hydraulic parameters i ncluding velocity and depth have been measured in different slope locations and flow discharges, further more, the resistance characteristic of overland flow has been also discussed according to the average Wei sbach-Darcy coefficient method and the improved calculating method considering the variations of hydra ulic factors along slope distance. The results show that the overland flow velocity and the depth vary alon g the monitoring distance in the experimental slope, the velocity increases as the slope distance increases on smooth and adhering sand slope, however, the peak and lower values appear on the adhering sand slop e with larger slope degree. On the other hand, the traditional resistance method, i. e., the average Weisbac h-Darcy coefficient method, is not feasible to analyze the flow resistance in smooth slope and roughness s lope with steep degree; while the improved method considering variations of hydraulic factors along slop e distance presents better performance to estimate the overland flow resistance.