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Table Of Contents
Chapter 5 Working with Hydrology Commands
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11 In the Left Slope and Right Slope boxes, type a left and a right slope value. You
can also click Select to specify the slope values by selecting points on the
drawing. These values can be zero.
The box in the top right area of the dialog box displays a graphic of the
currently defined channel. Based on the values you entered, information about
the channel is calculated and displayed below the channel graphic. This
information is for display only and cannot be edited.
NOTE
If the data that you entered has an error, the channel graphic image does
not display. Check for an error message at the bottom of the dialog box.
12 Click OK to exit the dialog box.
Calculating Culvert Size and Shape
The Culvert Calculator can aid in designing a box or circular culvert comprised
of single or multiple barrels. You may specify various end treatments, such as
headwalls and wingwalls, and design for inlet and outlet control situations.
Also, all runoff methods are accessible from the Culvert Calculator for use in
determining design flows.
The following list summarizes a typical culvert design process:
Culvert Design Process
Steps What to do
Determine the location of the
culvert. This is often a natural
stream bed.
Look at the drawing to determine where the culvert should
be located.
If needed, you can build a surface model using the Terrain
Model Explorer. Use Slope Arrows to show the slopes of the
surface and to determine where the natural flow occurs
across the surface, and use the Watershed commands to
delineate the catchment areas.
Calculate the runoff for the
area using the design storm
frequency required by state or
local agencies, and develop
the inflow hydrograph.
Use one of the four Autodesk Civil Design runoff calculation
methods. You can use them independently, or you can run
the commands from within the Culvert Calculator.
Determine culvert design
parameters (refer to list
below).
Use the Culvert Calculator.
Develop a preliminary culvert
design, then use both inlet
and outlet control calculations
to determine the governing
control factor.
Use the Culvert Calculator.