Abstract: The present study aims to research the calculation method of normal water depth,Froude number and contracted section’s water depth in standardⅠ-type horseshoe cross section. On the basis of the theories of uniform flow and non-uniform flow in open channel and the energy equation,hydraulic characteristics of standardⅠ-type horseshoe cross section are analyzed. Iterative calculation formulas of the relationship between normal water depth and flow,Froude number under three conditions and water depth of contracted section under two conditions are put forward. The calculating process is illustrated by examples. The calculation method is simple and convenient with high precision,hence can be applied to engineering practice.

Key words: standardⅠ-type horseshoe cross section , normal water depth , Froude number , water depth of contracted section