Subbasin TOC Data Table Edit Command

The Subbasin TOC Data Table Edit command allows the user to view and edit all subbasin TOC data in a single editable table. Note that the table will display TOC data only after it has been calculated using the Subbasin TOC Data command. Refer to this article in our knowledge base to learn more about Subbasin TOC Data command.

Follow the steps below to use the Subbasin TOC Data Table Edit command:

1. From the Input ribbon menu, click on the Drainage Subbasins dropdown menu and then select the Subbasin TOC Data Table Edit command.
   
2. The Subbasin TOC Data Table Edit dialog box will be displayed.
   

The following sections describe the Subbasin TOC Data Table Edit dialog box.

Subbasin TOC Data Table

The following data entries are provided in the Subbasin TOC Data editable table.

Subbasin ID

This column lists all subbasins contained in the current scenario. The user can use the filter option from the column header to limit the subbasins displayed in the table.

TOC Segment

This column sequentially numbers the TOC segment from the most upstream to the most downstream segments.

Runoff Flow Type

This column having a dropdown combo box lists the available runoff flow types, as listed below.

• Channel Flow
• Pipe Flow
• Shallow Concentrated Flow (default for newly inserted rows)
• Sheet Flow
• Zero Travel Time (Ponds)
  

Flow Length

This column lists the length of the TOC segment. Clicking the […] button under this column causes the dialog box to temporarily disappear, allowing the user to measure the flow path segment length from the Map View.

Slope

This column lists the slope of the TOC segment. If the user has specified a Terrain elevation surface, then the user can measure the Flow Length from the Map View and the software will automatically compute the TOC segment slope.

If no Flow Length is defined, then this entry will be blank. If a Flow Length is specified and no Terrain Elevation Surface is defined, then the default value of slope will be 0.0300.

The user can click the [Recalc] button to recompute the segment slope for the defined flow length and elevation terrain surface. Similarly, the [Recal All] button allows the user to recompute the slope value for all the flow path segments available in the scenario at once.

Hydraulic Radius

This column will be enabled if Channel Flow or Pipe Flow is selected as the Runoff Flow Type. The default value of the Hydraulic Radius is 0.45 ft for the Channel Flow and 0.29 ft for the Pipe Flow.

Surface Roughness/Type

This column changes its behavior depending upon the Runoff Flow Type selected. When Sheet Flow is selected as the Runoff Flow Type, then an entry field with a lookup […] button will be displayed in the corresponding Surface Roughness/Type column field. If Sheet Flow is selected as the Runoff Flow Type, the default value for the corresponding Surface Roughness/Type column will be 0.40000.

Clicking the […] button under the Surface Roughness/Type column displays the Overland Flow Roughness lookup dialog box.

When Shallow Concentrated Flow is selected as the Runoff Flow Type, then a dropdown combo box will be displayed in the corresponding Surface Roughness/Type column field with the following entries.

• Unpaved (default entry)
• Agricultural Crops
• Bare Ground
• Forest With Underbrush
• Forest Without Underbrush
• Long Grass
• Paved
• Short Grass
  

When Channel Flow is selected as the Runoff Flow Type, then an entry field with a lookup […] button will be displayed in the corresponding Surface Roughness/Type column field. If Channel Flow is selected as the Runoff Flow Type, the default value for the corresponding Surface Roughness/Type column will be 0.04500.

Clicking the […] button under the Surface Roughness/Type column displays the Manning’s Roughness lookup dialog box.

When Pipe Flow is selected as the Runoff Flow Type, then an entry field with a lookup […] button will be displayed in the corresponding Surface Roughness/Type column field. If Pipe Flow is selected as the Runoff Flow Type, the default value for the corresponding Surface Roughness/Type column will be 0.01300.

Clicking the […] button under the Surface Roughness/Type column displays the Channel and Pipe Manning’s Roughness lookup dialog box.

When Zero Travel Time (Ponds) is selected as the Runoff Flow Type, then the Surface Roughness/Type column field becomes read-only. This option is used for flow segments that pass through a reservoir, lake, pond, or other structure where travel time is considered negligible or zero.

Velocity

This column lists the computed flow velocity.

TOC

This column lists the computed Time of Concentration (TOC) value.

Terrain Elevation Surface

The Terrain elevation surface dropdown entry is used to select the terrain surface available in the project. The dropdown entry by default is set to the current scenario’s terrain surface.

Precipitation Data Source

The Precipitation data source dropdown entry is used to select the precipitation data source for regions such as Austria, Germany, Ontario (Canada), and the USA. The precipitation data source is used for computing the 2yr-24hr rainfall depth data for the selected location.

The available precipitation data source options are:

• Austria – Bundesministerium Wasserwirtschaft eHYD Data Service
• Canada – Environment Canada & Ontario Ministry of Transportation
• Canada – Ontario Ministry of Transportation
• Germany – Deutscher Wetterdienst – Klima und Umwelt
• USA – NOAA Atlas 2 (PFDS) Precipitation Frequency Data Server
• USA – NOAA Atlas 14 (PFDS) Precipitation Frequency Data Server (default)
• USA – ISWS (Illinois) Bulletin 75 (PFDS) Precipitation Frequency Data Server
• USA – SUDAS (Iowa) Bulletin 71 (PFDS) Precipitation Frequency Data Server
• USA – NRCC (Northeast Regional Climate Center) PFDS

Note: The specific precipitation data source entry will be displayed based on the selected location.

2yr-24hr Rainfall Depth

The 2yr-24hr rainfall depth entry stores the 2-year 24-hour rainfall depth for the sheet flow computations. Clicking the [Retrieve] button retrieves the rainfall data for the selected location.

After defining or editing the required table value(s), click the [Compute] button to calculate the results of the Subbasin TOC Data table.

Exporting Subbasin TOC Data Table

After computing the subbasin TOC data, click the [Export] button to export the subbasin TOC tabular data into a spreadsheet. Alternatively, right-click on any of the column headers or editable table cells and select Export Table to Excel or Export Table to PDF command from the context menu to export the data into the required format.