Physical Alternative for Ponds
The physical alternative editor for ponds is used to create various data sets for the physical characteristics of ponds. The following columns are available:
| Column | Description |
|---|---|
| ID | Displays the unique identifier for each element in the alternative. |
| Label | Displays the label for each element in the alternative. |
| Infiltration (Average) | Specify the average infiltration rate for the pond. This value only applies when the Pond Infiltration Method is set to Average Infiltration. |
| Constant Flow | The flow that exits the pond via infiltration during each time step. This value only applies when the Pond Ifiltration Method is set to Constant Flow. |
| Pond Infiltration Method | Ponds can lose water by infiltration into groundwater. Any water lost by infiltration does not show up in downstream links. You can specify "None" (default) if pond infiltration is not being considered, or you can use one of the following ways to enter pond infiltration rates: 1. a Constant Flow rate given in flow units 2. an Average Infiltration rate in depth per unit time which is multipied by the area of the pond surface at that time step to determine the infiltration rate. In applying either method, the model also has a stability filter when the pond water depth is below 0.5 ft so that the infiltration rate will linearly reduce to zero as the depth decreases to zero. |
| Invert (Stop) | Lets you define the downstream invert of the pipes. This column is available only when the Volume method is Pipe. |
| Invert (Start) | Lets you define the upstream invert of the pipes. This column is available only when the Volume method is Pipe. |
| Volume Type | Specifies which of the four volume methods (Elevation-Area, Elevation-Volume, Pipe, or Functional) is used for each pond in the alternative. Clicking a field in this column allows you to switch between them. |
| Pond Constant | "C" value in the expression A*Depth^B+C for Depth in feet. This field is available only when the Functional Volume Type is chosen. |
| Pond Exponent | "B" value in the expression A*Depth^B+C for Depth in feet. This field is available only when the Functional Volume Type is chosen. |
| Pond Coefficient | "A" value in the expression A*Depth^B+C for Depth in feet. This field is available only when the Functional Volume Type is chosen. |
| Depth (Maximum) | Lets you define the maximum depth, or water surface elevation, of the pond. |
| Elevation (Invert) | Lets you define the invert elevation of each pond in the alternative. |
| Number of Barrels | Lets you define the number of barrels the Pipe Volume uses. This column is available only when the Volume method is Pipe. |
| Length | Lets you define the length of the pipes. This column is available only when the Volume method is Pipe. |
| Pipe Diameter | Lets you define the diameter of the pipes. This column is available only when the Volume method is Pipe. |
| Elevation-Volume Curve | Opens the Elevation-Volume Curve dialog box, allowing you to define the elevation-volume curve for each pond in the alternative that uses the Elevation-Volume Curve Volume Type. |
| Elevation-Area Curve | Opens the Elevation-Area Curve dialog box, allowing you to define the elevation-area curve for each pond in the alternative. |