2.0

Defining Pond Slopes
105
Defining the Pond Bottom by Using the Daylight
Option
When you select the daylight option, the Select Surface dialog box is displayed.
The project must contain a surface in order to use the daylight option.
1 Follow steps 16 in Applying a Linear Slope to a Pond in this chapter.
2 Select the surface you want the pond perimeter to daylight to, and then click OK.
The following prompt is displayed:
Slope – Grade/Slope/<1.0000:1>:
3 Do one of the following to define the slope or grade:
n
Type G for Grade and enter a grade value (e.g., 5.00).
n
Type S for Slope and enter a ratio (e.g., 20:1).
After you define the slope, the slope pattern is generated and the following
prompts are displayed:
Slope: 20.0000:1, Grade: 5.0000%
Linear slopes attached to all vertices successfully.
Shape Pond - All? <Yes>:
4 Type Yes to import the pond contours, bottom polyline, and slope control lines
automatically, or type No to end the command.
If you choose to shape the pond, then the following prompt is displayed:
Close contour lines? Yes/No: <Yes>:
5 Type Yes to create closed contour lines, or type No to draw contours that skip
the last segment of the perimeter.
NOTE
If the Pond Contour Settings are set up to create both normal and
highlight contours, then the close contour lines prompt is displayed twice.
When you use the Daylight option, pond contours and a daylight line are
created for the pond. The daylight line is created on the normal contour layer.
The daylight line is the lowest contour-looking object that goes entirely around
the pond. When you use the LIST command to list its properties, you can see
that its vertices are created at different elevations.
Often, the pond contours that are created do not go all the way around the
pond. This is because the contours stop when they fail to cross a slope control
line at the same elevation. If you select the option to close contour lines, then
these contours close back to their start points.
Applying a Slope to a Pond By Specifying the
Required Pond Volume
If you know the required storage volume for a detention/retention pond, then
you can use this volume to create the pond slope design.
NOTE
Use the Detention Basin Storage command to determine the required
storage volume for a pond based on one or more inflow hydrographs.