Channel Geometry

To perform the hydraulic analysis for an open channel with a specific geometry, the following elements are most commonly used: y is the flow depth from the free surface to the bottom of the channel; b is the width of the channel bottom; A is the cross sectional area normal to the flow direction; P is the wetted perimeter measured as the length of the line of contact with the water and the channel; and B is the top width at the free surface. Other geometrical elements used to designate the geometry of the channel cross section are the hydraulic radius R and the hydraulic depth D, defined as