The ratio of the depth of flow to the hydraulic radius for the most economical trapezoidal section, in open channel flow is_____________________? August 27, 2021March 9, 2019 by admin The ratio of the depth of flow to the hydraulic radius for the most economical trapezoidal section, in open channel flow is_____________________? A. 0.5 B. 1 C. 1.5D. 2