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Chapter 5 Working with Hydrology Commands
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Hydrology Overview
Autodesk Civil Design provides a set of tools you can use to perform a
hydrological analysis of a site and to design hydraulic structures to control post-
development runoff. You can use AutoCAD Land Development Desktop to
create the terrain model and calculate the watershed subareas of the site, and
then you can use one of four Autodesk Civil Design runoff calculation methods
to determine the peak discharge and hydrograph for the chosen design storms.
As part of your stormwater management plan for the site, you can then
determine how best to control the site runoff. You can use the pond grading
and routing commands to design detention ponds for attenuating the runoff,
and to design the inflow and outflow structures for the pond.
You can use the Autodesk Civil Design hydraulic-structure calculators to design
the pond inflow and outflow structures, such as risers, orifices, and culverts, as
well as to calculate channel flow for the time of concentration and time of
travel calculations.
Hydrology and hydraulics is an inexact science that usually involves a iterative
process of trial and error. You might begin with an estimate of where the
stormwater control devices would best be placed on a site, and then calculate
the runoff. From the runoff results, you can design your detention pond. You
can use the Pond Outflow Design dialog box to add multiple-stage structures
and make them active or inactive, so you can calculate the routed hydrograph
using several variations of structures until you get the results you need.
To help you learn how to use the hydrology commands, some sample files are
installed in the c:\Program Files\Land Desktop R2\data\hd folder. These files
include hydrograph files, intensity-duration files, and many others. For more
information on these sample files, see the following section, Sample Hydrology
Files that are Included with Autodesk Civil Design.
NOTE
For a list of references used for this section of the manual, see Hydrology
Bibliography at the end of this chapter.
Sample Hydrology Files That Are Included with Autodesk
Civil Design
When you install Autodesk Civil Design, sample hydrology files are installed
into the c:\Program Files\Land Desktop R2\data\hd folder. You can use these
files to help you learn how to use the Hydrology commands.
The following table lists the file names and descriptions. You can load these files
into the appropriate dialog box (for example, load the sample.clt file into the
Culvert Calculator) to see the data.