Resistance Variables for Sheet Flows on Portland Cement Concrete Surfaces.

摘要

The purpose of the study was to develop reliable hydraulic resistance variables for sheet flow runoff on Portland cement concrete surfaces. Present highest state of the art is a multiple regression equation for hydraulic flow depth without a fundamental resistance variable. Both uniform flow and rainfall-runoff situations were investigated. Experimental research was performed using artificial rainfall equipment on Portland cement concrete surfaces. Three surface roughness defined by mean texture depths of 0.010, 0.027, and 0.044 inches were tested at each of three slopes of 0.005, 0.015, 0.025. The uniform flow rates used ranged from very low flows up to approximately the largest flow rate possible without the development of roll waves. A total of 73 data sets, the consequence of approximately 3300 data points, was determined from uniform flow testing.