Inlets are typically created in AutoCAD Civil 3D as junction structures with an Inlet Location property of On Grade or On Sag.Create the pipe network (including inlets, pipes, manholes, and an outfall location), and run the Apply Rules command on each structure and pipe in the pipe network before running the Analyze Gravity Network command.When you are using the Analyze Gravity Network wizard you will need to be able to specify the cross slope of the lane, longitudinal slope, gutter width, and cross slope of the gutter for each inlet. You can begin the workflow for sizing pipes after the following prerequisites are established. The Compute Energy and Hydraulic Grade Lines analysis follows the procedure outlined in Section 7.5, "Energy Grade Line Evaluation Procedure.".Both analysis types perform an inlet analysis which follows the procedure outlined in Chapter 4, "Pavement Drainage." The inlet analysis analyzes the flow captured by the inlets, computes the spread, and includes the results in the exported.Department of Transportation Federal Highway Administration. 22 (HEC-22), Third Edition, published by the U.S. The calculations are based on the Urban Drainage Design Manual, Hydraulic Engineering Circular No. Selecting both options applies the resulting properties, including the computed energy and hydraulic grade values, to the affected parts. Applying the results of the analysis will apply the calculated energy and hydraulic grade values to the affected parts in the pipe network. You have the option to apply these results to the pipe network from the Results page of the wizard. Compute Energy and Hydraulic Grade Lines: Calculates the energy and hydraulic grade lines, and then displays a graphical preview of the results (if a profile view is present in the drawing).To calculate hydraulic properties, select theĬompute Energy and Hydraulic Grade Lines check box. Note: This option does not calculate hydraulic properties (EGL and HGL).