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Chapter 2 Working with Ponds
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Overview of Working with Ponds
You can use the Ponds and Hydrology commands in Autodesk Civil Design to
create and edit ponds and any type of water-retention structure.
Typically, the first step in a detention design is to use Runoff commands in the
Hydrology menu to calculate the runoff from the watershed and to create the
inflow hydrograph for the design storms.
You can estimate the size of detention pond you will need by using the
Detention Basin Storage method. Based on your inflow runoff and your
allowable peak discharge, this gives you a very good estimate for the size of the
detention pond needed.
Next, you establish the preliminary pond location and size by drawing and
editing the pond perimeter until the pond perimeter shape and size are
satisfactory. The pond perimeter is a polyline, and you can calculate subsequent
slopes from each vertex in the polyline.
There are four groups of commands on the Grading menu that you can use to
define ponds and shape them:
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Define Pond: Use these commands to quickly name or rename a pond by
selecting a polyline perimeter, to define the 3D pond geometry by selecting
existing contours, or to delete a pond from the drawing. You can also define
a pond when using the Pond Perimeter and Pond Slopes commands.
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Pond Perimeter: Use these commands to draw a pond perimeter, change its
elevation, add vertices to the perimeter, fillet the perimeter, and save and
import perimeter shapes.
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Pond Slopes: Use these commands to grade the bank of the pond. You can
create a pond bank template to apply to the pond, or apply linear or multiple
slopes to the bank. At the end of these commands, you are prompted to
shape the pond (see below). If you respond No to this prompt, then you can
use the Shape Pond commands to shape the pond later.
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Shape Pond: Use these commands after you have created the pond slope
design. Shaping a pond creates the 3D pond data: the pond contours, the
pond bottom, and the slope control lines (breaklines). A shaped pond is
required when using the Hydrology commands because these commands
depend on the 3D pond information. You can also use the Shape Pond
commands on the Grading menu to shape a pond.
The next step in pond design is to do a preliminary design of the outflow
structures. Then you can calculate routed hydrographs using the Storage
Indication Method.
You can use the Storage Indication Method command to perform pond routing
with multiple upstream ponds. This command uses a post-development
hydrograph, stage-storage curve, and stage-discharge curve (as well as an
optional pre-development hydrograph) to route runoff.