Design the Pond Hydraulics
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The Pond Outlet Structure Feature has a “doorway to a whole new hydraulic world”: the Composite Outlet Structures dialog
In the Pond Outlet settings group, with Has Control Structure set to Yes, you can select <Edit Composite Outlet Structure>.
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The Composite Outlet Structures dialog is the bulk of hydraulic Pond Design.
It’s a Collection of “Composite Outlet Structures”
Each Composite Outlet Structure is a collection of structures with geometric and hydraulic properties. Multiple structures can exist and be routed in parallel or in series. Each can be renamed.
Ratings Curves can be shown for individual or composite structures (calculated with the Compute button on this dialog)
You can have multiple composite structures defined, but only one is active during a (Scenario) Compute.
CivilStorm supports Interconnected Ponds (varying tailwater). We’ll want Free Outfall here.
Note that Minimum and Maximum Headwater is linked to the Elevations defined in the connected Pond when Use Pond for Headwater Range is selected.
Let's add a Discharge Weir
- Select the Pond Feature.
- Set Has Control Structure to Yes.
- In the Composite Outlet Structure click <Edit Composite Outlet Structure>.
This opens the Composite Outlet Structure dialog.
Define a Weir as the Primary Control Structure
- Click New > Composite Outlet Structure
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This is where you enter the physical (geometry, elevation, hydraulic) characteristics of the controls structure - in this case a weir.
Flow Direction should be Forward Flow Only.
Ensure that the Type of Weir, Elevation, Length, Coefficient are set.
Note that Downstream ID can be Tailwater or it can be another defined control structure (for serial control).
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Once you have defined your control structure(s), you can "do the math".
Note that CivilStorm's PondMaker tool provides pond sizing and outlet control design guidance. It is fairly complex and outside the scope of this discussion.