《《13-30-10》.pdf

State of Wisconsin Department of Transportation Facilities Development Manual ORIGINATOR PROCEDURE Director, Bureau of Highway Development 13-30-10 CHAPTER 13 Drainage SECTION 30 Channels and Road Ditches SUBJECT 10 Hydraulic Design of Open Channels This procedure presents the theory, design criteria, basic equations, and design procedures necessary to hydraulically design open channels.When designing open channels, the designer must be knowledgeable about the types of flow channel design characteristics and the basic hydraulic equations. With this background information, the designer may design stable channels through application of the flexible lining criteria and design techniques discussed in this procedure. The design techniques along with example problems presented in this procedure are: 1. Flexible Lining Design 2. Steep Side Slope Protection 3. Bend Protection Design In addition, water surface profiles for specific channels with varying hydraulic characteristics may be computed as described under Water Surface Profiles, HEC-2. (See Procedure 13-20-1 for additional information) Types of Flow Steady Flow and Unsteady Flow: Time is the criterion. The flow at any cross section is said to be steady if the velocity does not vary in magnitude or direction with time; and, conversely, the flow is called unsteady if the velocity varies with time. In most open channel flow problems, flow conditions are studied under steady flow conditions only. Uniform Flow and Varied Flow: Space is the criterion. Flow is said to be uniform when the depth of flow and the mean velocities are the same at successive cross sections in any reach. Uniform flow may only occur in a channel with a constant cross secti