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Click to download the Introductory [US units] tutorial model files.

Add Detention Vault

Since CAD does not represent Stormwater Controls (i.e. Ponds, Swales, Raingardens) as richly in Plan as xpdrainage does, the Pipe Network that was imported is overly simplified and uses ‘dummy’ objects as placeholders for designers who are forced to split their work between several tools. To achieve proper Runoff Mitigation an Underground Detention Vault needs to be added, which can be easily done by converting the ‘dummy’ junction into a full Stormwater Control (SWC).

Right-click Standard MH (11) and select Change Template.


Select Parking Vault from the Template list and change the Label name to Vault. Select OK to close the dialog.

Double-click or right-click and select Edit to review the Vault SWC properties. Notice void ratio is set to 95% based on manufacturers specifications and that the facility is 4ft deep. The area that the facility extends is represented by the footprint shown in Plan view. Any change to input which would affect the facility extents will be represented in Plan, just like any changes to the Plan layout will update dimension details within the SWC properties. Use the Click to Show Images icon in the lower left of the dialog to view a schematic of what the parking vault looks like.

Under the Outlets tab, from the Outlet Type dropdown list, select Weir and ender a width of 3ft and set the crest level to 169.5. This will set a 3ft wide broad crested weir 3.5ft above the base of the vault. Select OK to close the SWC dialog.

Reconnect System

Since xpdrainage allows for ‘AS-BUILT’ layout and details of stormwater systems, it is valuable to place the Inlets and Outlet of this facility at the real world proposed locations to ensure connection inverts, lengths, and slopes are accurate. Right-click the Vault SWC and select Specify Inlet/Outlet Location, select one of the Inlets/outlet. You can then drag and drop the Inlet/Outlet to the appropriate location. Repeat process for all objects until they are located as shown.

When the Pipe Network was imported any Junctions which fall on unconnected Inflow Areas are automatically connected to the adjacent Junction. If there are multiple Junctions imported on top of the same Inflow Area, only one will be connected, so it is important to review if all of the automatic connecting occurred as expected. In the case of Comm (3) and the Vault SWC, it appears that the Inflow Area connected automatically to the structure downstream of the Vault SWC. This can be easily updated by right click on Comm (3) and select Reconnection Inflow. Then place the inlet next to the parking island as shown.

Since the Inflow Area was reconnected to the Vault SWC the previous inlet connection at Standard MH (5) immediately downstream of the Vault needs to be removed. Edit the Manhole and under the Inlets tab, select the Inlet name which does not have a check for Incoming Item and select the Remove [-] button as shown below. This will ensure that only Inlets connected to model elements will exist.

Now the Vault SWC has been configured, add a flow path as shown in order to view a Profile of the drainage system. Right-click the Flow Paths layer, select Add and click once on the Junction at the top-middle of the site then once at the downstream most Junction at the lower right corner of the site. Hit the Esc key to end the action, then right click on the Flow Path layer and select Show Profile.

Automatically Correct Data

Just like in the Plan view, the Flow Path shown in the Profile view can be zoomed into by using the mouse wheel and panned by using the mouse or by the view controls in the top left of the dialog. Notice in the Profile that while the Pipe Connections which were imported from GIS were brought into the software at the correct invert elevations the Junctions between pipes are not set to the correct elevations. Close or minimize the Profile view and under the Pipe Networks ribbon select Synchronize Manhole Invert Levels. This will Automatically set the manhole inverts to the lowest connected pipe connection.

View the Flow Path Profile view again to see the corrected pipe network.

Size Pipe Network

Now that the Vault SWC has been added and configured, Automatically Size the Pipe Network within the Connections form by double clicking on the Connections Layer on the Tree View, or by select Connections on the Pipe Networks ribbon.

Pipe Networks can be sized based on Flow Paths - select a Flow Path from the drop down list and notice that the Connections list is sorted with Connections and Branch Lines based on the Flow Path selection. Sizing will occur for all Connections contained in the Flow Path and all Branch Lines. Select Auto Size to perform preliminary sizing of the Pipe Network.

Once the Auto Size is performed the diameters of many of the pipe Connections are upsized based on the Pipe Sizing Results, listed below the Connections Input table. Design Constraints and Sizing IDF input is controlled by the Pipe Sizing Criteria options under the Pipe Networks ribbon.

Select OK to apply the newly upsized Connection diameters and to close the Connections form.

Validate System Data

For a system wide check for any potential discrepancies, under the Analysis ribbon select either Validate or Go – this will run an audit of the storm system and list any potential issues in the model.

While the Junction levels have already been corrected to match the Connection levels there is still a data inconsistency that was found due to small adjustments made during the Auto Size process. By checking the Levels box the inconsistencies can automatically be updated - select Apply to apply automatic update.

At this point all inconsistencies between the Junctions and the Connections have been noticed and automatically corrected. The Validate dialog shows no discrepancies are outstanding. Select OK to close the dialog.

Now the stormwater system is ready for full hydraulic analysis – browse to the Analysis ribbon and select Go to solve the model.