2.0

Chapter 2 Working with Ponds
100
Defining a Pond Perimeter from Contours
You can use the By Contours command to base the pond geometry on contours
that exist in your drawing, such as contours that represent a natural depression.
You can use contours that were generated from a surface or a grading object, or
you can use contours that you've drawn using the grading tools. Contour
increments should typically not be greater than 1 foot for accurate pond
volume calculations, and contours should not contain arcs.
The By Contours command creates all the necessary 3D pond information from
the contours you select. The contour with the highest elevation is used as the
pond perimeter; the contour with the lowest elevation is used as the pond
bottom.
This command creates a <pond name>.pnd file in the
c:\Land Projects R2\<project name>\hd folder.
To define a pond perimeter from contours
1 From the Grading menu, choose Define Pond ä By Contours to display the
Pond Name dialog box.
2 In the Pond Name text box, type a name for the pond (up to 8 characters), and
then click OK.
The following prompt is displayed:
Select by Layer/<Selection>:
3 Do one of the following to select the contours:
n
Type Selection, press ENTER, and then select the contour(s) that you want to
define as the pond.
n
Type Layer, press ENTER, and then select a contour on the layer that you
want to select.
4 Press ENTER.
If you select a contour object, instead of a polyline, then the following prompt
is displayed:
Selection contains Contour entities. Convert? <Yes>:
5 Type Yes to change the contour objects into 3D polylines and add the pond
information to them. If you type No, then the command ends and the pond is
not defined.
6 Press ENTER to end the command.
Deleting Ponds
Use the Delete Pond command to selectively delete pond elements from your
drawing, and to delete the pond definition file or the pond outflow file from
the project folder.
When you define a pond, the pond definition data is stored in an external file,
<pond name>.pnd, in the c:\Land Projects R2\<project name>\hd folder. This
file contains elevation, area, and perimeter data for each pond contour. When
you delete a pond, you can choose to delete this file, or to delete the pond rim
(perimeter) data, the contours, the slope control lines, the bottom polyline, the
outflow file, or all pond elements.