Urban Drainage using RiverFlow2D and EPA-SWMM¶
This tutorial illustrates how to apply the RiverFlow2D Urban Drainage module that integrates surface flooding with EPA-SWMM storm drain model. The project objective is to assess the shallow inundation originating from a surcharging underground pipe. The procedure involves the following steps:
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Create a SWMM application.
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Open an existing RiverFlow2D model.
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Import the surface-storm drain exchange points from the'.INP' SWMM file.
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Generate the mesh.
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Export the files of RiverFlow2D.
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Run the model.
::: shaded The files required to follow this tutorial can be extracted from the 'ExampleProjects' zip file under the 'UrbanDrainageTutorial' folder. This zip file is downloaded separately from your installation materials. :::
The pipe is modeled in 1D and connected to the 2D mesh through a manhole. The modeled area is approximately 0.4 km by 0.96 km (see Figure 12.1). A storm drain of circular section of \(1.4 m\) in diameter and 1340 m in length is assumed to run through the modeled area. The pipe Manning's roughness is set to n=0.017. An inflow boundary condition is applied at the upstream end of the pipe, illustrated in Figure 12.2. A free outfall is considered as downstream boundary condition. A base initial flow of 1.6 m\(^3\)/s is set as uniform initial condition. A surcharge is expected to occur at a vertical manhole of 1 m\(^2\) cross-section located 467 m from the top end of the culvert at the coordinates (x=264,896 m,y=664,747 m). The profile geometry of the culvert is given in Table [pipe012] and shown in Figure 12.3.
| c c c c c Node | Distance from upstream inlet (m) | Invert level (m) | Reach length (m) | X | Y |
|---|---|---|---|---|---|
| N1 | 0͡ | 39.17 | - | 264896.000 | 664747.000 |
| N2_manhole | 467͡ | 29.46 | 467 | 264896.000 | 664747.000 |
| N3 | 571͡ | 27.70 | 104 | 265633.232 | 664154.002 |
| N4 | 677͡ | 26.37 | 106 | 266474.164 | 663829.787 |
| N5 | 877͡ | 25.70 | 200 | 267730.496 | 663302.938 |
| N6 | 991͡ | 24.64 | 114 | 268470.111 | 662978.723 |
| N7 | 1145͡ | 24.29 | 154 | 269533.941 | 662725.431 |
| Out1 | 1340͡ | 23.49 | 195 | 271874.367 | 661752.786 |
Storm drain configuration in EPA-SWMM¶
::: shader If you want to skip this step, you may want to use the SWMM 'base.INP' in the tutorial folder. In that case, please go to section 12.1.1. :::
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Open the SWMM application.
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The first step consists in setting the position of all the nodes that conforms the drainage network by means of the button Add a junction node:
On the Study area map window, click as many times as nodes should be added to the network. In this project there will be 8 nodes. Note that the position of the nodes is schematic:
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Configure the node data by double-clicking on each node. The node properties window should appear:
image image
In this example, the most relevant parameters are: Name, X- and Y-Coordinates, Inflows, Invert elevation and Max. depth. The only inflow nodes are N1 and N2_manhole. Node N2_manhole should have Max. depth=2 m. Node N1 is the discharge input and should follow the time series given in Figure 12.2.
The time series can be inserted point-by-point or read from file. On the other hand, node N2_manhole will be the connection with the surface domain and the baseline values should be 0.0:
image image
The outfall node Out1 should be configured as free:
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Join the nodes by means of the Add a conduit link tool:
The result should look like the following figure:
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Configure the link properties by double-clicking on each one:
The most relevant properties are: Name, Inlet node, Outlet node, Shape, Max. depth, Length, Roughness and Initial flow.
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Once the network is completely configured, the project should be saved in order to generate the '.INP' file that should be similar to the one shown below.
[EVAPORATION]
;;Data Source Parameters
;;-------------- ----------------
CONSTANT 0.0
DRY_ONLY NO
[JUNCTIONS]
;;Name Elevation MaxDepth InitDepth SurDepth Aponded
;;-------------- ---------- ---------- ---------- ---------- ----------
N1 39.17 0 0 0 0
N2_manhole 29.46 2 0 0 0
N3 27.7 0 0 0 0
N4 26.37 0 0 0 0
N5 25.7 0 0 0 0
N6 24.64 0 0 0 0
N7 24.29 0 0 0 0
[OUTFALLS]
;;Name Elevation Type Stage Data Gated Route To
;;-------------- ---------- ---------- ---------------- -------- ----------------
Out1 23.49 FREE NO
[CONDUITS]
;;Name From Node To Node Length Roughness InOffset OutOffset InitFlow MaxFlow
;;-------------- ---------------- ---------------- ---------- ---------- ---------- ---------- ---------- ----------
L1 N1 N2_manhole 467 0.017 0 0 1.6 0
L2 N2_manhole N3 104 0.017 0 0 1.6 0
L3 N3 N4 106 0.017 0 0 1.6 0
L4 N4 N5 200 0.017 0 0 1.6 0
L5 N5 N6 114 0.017 0 0 1.6 0
L6 N6 N7 154 0.017 0 0 1.6 0
L7 N7 Out1 195 0.017 0 0 1.6 0
[XSECTIONS]
;;Link Shape Geom1 Geom2 Geom3 Geom4 Barrels Culvert
;;-------------- ------------ ---------------- ---------- ---------- ---------- ---------- ----------
L1 CIRCULAR 1.4 0 0 0 1
L2 CIRCULAR 1.4 0 0 0 1
L3 CIRCULAR 1.4 0 0 0 1
L4 CIRCULAR 1.4 0 0 0 1
L5 CIRCULAR 1.4 0 0 0 1
L6 CIRCULAR 1.4 0 0 0 1
L7 CIRCULAR 1.4 0 0 0 1
[INFLOWS]
;;Node Constituent Time Series Type Mfactor Sfactor Baseline Pattern
;;-------------- ---------------- ---------------- -------- -------- -------- -------- --------
N1 FLOW discharge_inflow FLOW 1.0 1
N2_manhole FLOW "" FLOW 1.0 1.0 0.0
[TIMESERIES]
;;Name Date Time Value
;;-------------- ---------- ---------- ----------
discharge_inflow 0:00 1.6
discharge_inflow 0:02 1.6
discharge_inflow 0:04 1.6
discharge_inflow 0:06 1.6
discharge_inflow 0:08 1.61644
discharge_inflow 0:10 1.6336
discharge_inflow 0:12 1.65472
discharge_inflow 0:14 1.67188
discharge_inflow 0:16 1.68904
discharge_inflow 0:18 1.70488
discharge_inflow 0:20 1.71808
discharge_inflow 0:22 1.71808
discharge_inflow 0:24 1.7392
discharge_inflow 0:26 1.75636
discharge_inflow 0:28 1.77352
discharge_inflow 0:30 1.7986
discharge_inflow 0:32 1.82764
discharge_inflow 0:34 1.8448
discharge_inflow 0:36 1.88704
discharge_inflow 0:38 1.92136
discharge_inflow 0:40 1.95436
discharge_inflow 0:42 1.98868
discharge_inflow 0:44 2.02168
discharge_inflow 0:46 2.056
discharge_inflow 0:48 2.09824
discharge_inflow 0:50 2.1484
discharge_inflow 0:52 2.19988
discharge_inflow 0:54 2.25928
discharge_inflow 0:56 2.32264
discharge_inflow 0:58 2.3728
discharge_inflow 1:00 2.4784
discharge_inflow 1:02 2.56288
discharge_inflow 1:04 2.66056
discharge_inflow 1:06 2.77012
discharge_inflow 1:08 2.8876
discharge_inflow 1:10 3.0064
discharge_inflow 1:12 3.17536
discharge_inflow 1:14 3.29416
discharge_inflow 1:16 3.44992
discharge_inflow 1:18 3.61888
discharge_inflow 1:20 3.78784
discharge_inflow 1:22 3.9568
discharge_inflow 1:24 4.168
discharge_inflow 1:26 4.33696
discharge_inflow 1:28 4.50592
discharge_inflow 1:30 4.67488
discharge_inflow 1:32 4.83988
discharge_inflow 1:34 4.99168
discharge_inflow 1:36 5.16064
discharge_inflow 1:38 5.27944
discharge_inflow 1:40 5.41012
discharge_inflow 1:42 5.54476
discharge_inflow 1:44 5.67148
discharge_inflow 1:46 5.77312
discharge_inflow 1:48 5.89984
discharge_inflow 1:50 6.00148
discharge_inflow 1:52 6.10312
discharge_inflow 1:54 6.1876
discharge_inflow 1:56 6.24096
discharge_inflow 1:58 6.28111
discharge_inflow 2:00 6.28111
discharge_inflow 2:02 6.24096
discharge_inflow 2:04 6.1876
discharge_inflow 2:06 6.10312
discharge_inflow 2:08 6.00148
discharge_inflow 2:10 5.89984
discharge_inflow 2:12 5.77312
discharge_inflow 2:14 5.67148
discharge_inflow 2:16 5.54476
discharge_inflow 2:18 5.41012
discharge_inflow 2:20 5.27944
discharge_inflow 2:22 5.16064
discharge_inflow 2:24 4.99168
discharge_inflow 2:26 4.83988
discharge_inflow 2:28 4.67488
discharge_inflow 2:30 4.50592
discharge_inflow 2:32 4.33696
discharge_inflow 2:34 4.168
discharge_inflow 2:36 3.9568
discharge_inflow 2:38 3.78784
discharge_inflow 2:40 3.61888
discharge_inflow 2:42 3.44992
discharge_inflow 2:44 3.29416
discharge_inflow 2:46 3.17536
discharge_inflow 2:48 3.0064
discharge_inflow 2:50 2.8876
discharge_inflow 2:52 2.77012
discharge_inflow 2:54 2.66056
discharge_inflow 2:56 2.56288
discharge_inflow 2:58 2.4784
discharge_inflow 3:00 2.3728
discharge_inflow 3:02 2.32264
discharge_inflow 3:04 2.25928
discharge_inflow 3:06 2.19988
discharge_inflow 3:08 2.1484
discharge_inflow 3:10 2.09824
discharge_inflow 3:12 2.056
discharge_inflow 3:14 2.02168
discharge_inflow 3:16 1.98868
discharge_inflow 3:18 1.95436
discharge_inflow 3:20 1.92136
discharge_inflow 3:22 1.88704
discharge_inflow 3:24 1.8448
discharge_inflow 3:26 1.82764
discharge_inflow 3:28 1.7986
discharge_inflow 3:30 1.77352
discharge_inflow 3:32 1.75636
discharge_inflow 3:34 1.7392
discharge_inflow 3:36 1.71808
discharge_inflow 3:38 1.71808
discharge_inflow 3:40 1.70488
discharge_inflow 3:42 1.68904
discharge_inflow 3:44 1.67188
discharge_inflow 3:46 1.65472
discharge_inflow 3:48 1.6336
discharge_inflow 3:50 1.61644
discharge_inflow 3:52 1.6
discharge_inflow 3:54 1.6
discharge_inflow 3:56 1.6
discharge_inflow 3:58 1.6
discharge_inflow 5:00 1.6
[REPORT]
;;Reporting Options
INPUT NO
CONTROLS NO
SUBCATCHMENTS ALL
NODES ALL
LINKS ALL
[TAGS]
[MAP]
DIMENSIONS 260000.000 660000.000 270000.000 670000.000
Units Meters
[COORDINATES]
;;Node X-Coord Y-Coord
;;-------------- ------------------ ------------------
N1 264903.824 664753.843
N2_manhole 264896.000 664747.000
N3 265633.232 664154.002
N4 266474.164 663829.787
N5 267730.496 663302.938
N6 268470.111 662978.723
N7 269533.941 662725.431
Out1 271874.367 661752.786
[VERTICES]
;;Link X-Coord Y-Coord
;;-------------- ------------------ ------------------
Starting QGIS¶
Start the QGIS software. After loading we will have a window similar to the one shown below:
Start a new RiverFlow2D project¶
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In the RiverFlow2D toolbar, click on the New RiverFlow2D Project button
to start a new RiverFlow2D project. A dialog window appears where you select the layers that will be created, the Coordinate Reference System (CRS), and the directory path where the layers will be saved. This example will use the basic layers: Domain Outline, Manning N, and BoundaryConditions
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Select None in the Layers dropdown menu.
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Select the Projection button.
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In the Filter textbox, type 7405 and select the Coordinate Reference System as shown:
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Click OK.
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The Coordinate Reference System (CRS) EPSG code: 7405 should be selected, and the dialog window will look like this:
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Click the "..." button to provide a path to store the project files in the Project Directory textbox. For this example you may browse to the UrbanDrainageTutorial folder.
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After clicking OK, the layer templates are created, and displayed on the Layers Panel:
::: shaded RiverFlow2D will use the unit system as that defined in the projection you selected. If the projection has coordinates in meters, units will be set to Metric. If the projection coordinates are in feet, units will be set to English. :::
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On the QGIS Project menu, click Save, to save the project in the same directory that you previously selected in the Create New Project dialog above.
Load elevation data¶
RiverFlow2D uses elevation data in raster format. To load an ASCII grid file, from the Layer menu, click Add Layer, and then click Add Raster Layer... You may also click the Add Raster Layer button:
Search for the 'TEST8BDEM.ASC' in the 'UrbanDrainageTutorial\base' folder:
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Click Add, assign the EPSG:7405 projection code to the file, and raster will be displayed on the screen, by default it is rendered in gray gradient as shown in Figure 19.7.
::: shaded Right-clicking on the label of the created layer and selecting Properties allows you to change the rendering style for a more informative color palette. :::
And now the raster layer is displayed with the new color palette selected:
::: shaded It is convenient to move the raster layer created to the end of the list of layers, thus it does not interfere with the display of other layers. :::
Import the surface-storm drain exchange node connections from the SWMM .INP file¶
To connect the surface water mesh with the storm drain components, we will import the exchange nodes from the '.INP' file created in the first part of this tutorial. For that we will use the Import EPA-SWMM INP file command from the RiverFlow2D tools drop down icon:
Select the 'base.INP' file and a message will indicate the transfer was successful:
You will note that there is a new StormDrain layer created and the imported exchange nodes are displayed:
Create the limits of the modeling area¶
The limits of the modeling area are defined using a polygon on the Domain Outline layer. To create it do as follows:
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Click the Domain Outline layer to activate it and then click Toggle Editing (pencil) in the toolbar:
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This activates the rest of the editing buttons. Now click the Add Feature tool which is the bean looking polygon.
Proceed to delineate the outline of the polygon by marking the vertices clicking with the left mouse button:
::: shaded Make sure that the polygon is contained within the limits of the raster layer since RiverFlow2D will not extrapolate elevations to areas that are outside of the available data on the raster layer. Also, the SWMM exchange nodes should be inside the Domain Outline polygon. :::
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To finalize and close the polygon, right-click anywhere on the map view area. A dialog window to input the cell size attribute of the newly created polygon. The value for the reference size of the mesh cell is indicated. Enter a value of 10 m.
Now click on Toggle Editing button to deactivate the layer Edit mode and save the changes.
The Domain Outline is now complete.
Assigning Manning's n¶
To assign Manning's n roughness values, we will enter polygons with given n's. There can be as many polygons as those required to reproduce the spatial variability of this parameter. In this example, a single polygon will be drawn for the entire area.
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Select the Manning N layer and click the Toggle Editing button:
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Draw the polygon around the entire domain taking care that it covers all the cells.
You should have an image like the one shown below:
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Close the last vertices on the polygon by right-clicking on the desired position. The following dialog window is presented where you must input the Manning's n value associated to the polygon. For this case, enter 0.03:
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Click the Save button
and then click the Editing Tool button
to deactivate editing mode.
Imposing the boundary conditions¶
By default all boundaries are closed unless we set open boundary conditions. Since in this project flow is input from the storm drain, we will set only outflow conditions. To define the boundary conditions draw a polygon that includes the nodes or vertices at the left end of the mesh as indicated in the figure:
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Select the BoundaryConditions layer in the Layers panel.
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Click the Toggle Editing button to add the polygons that are going to indicate the nodes on which the inflow and outflow conditions are established.
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To finish the polygon, right-click on desired location. A window to enter the attributes of the newly created polygon is displayed.
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The window contains a list to select the name of ID of this BC (Boundary Cond. ID), set Id to OUTFLOW condition, and from the list of boundary condition Types select Free Outflow.
Enter the data as shown in Figure 12.21 below:
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Click the Save
button: -
Click the Toggle Editing
button to exit editing mode.
Generating the triangular-cell mesh¶
Now that the Domain Outline has been set, the Manning's n entered, and the SWMM nodes have been imported, we can proceed to create the mesh using the GMSH program.
To run the plugin, on the the Plugins menu, click Generate TriMesh, or click on the icon:
The following figure shows the generated mesh. You will also see in the Layers panel two new layers: Trimesh and Trimesh_point:
::: shaded Before using the Export plugin, save the QGIS project. To accomplish this, from the Project menu, click Save. Name the project file 'UrbanDrainageTutorial.qgz'. :::
Exporting the files¶
Once the layers with the input information to the model have been created, the next step is to export from QGIS the data files required by the RiverFlow2D model.
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Run the *Export RiverFlow2D * plugin
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A dialog window is presented. We must indicate the raster layer of the Digital Elevation Model (DEM), as this layer is not created by the plugin and its name may be different.
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Using the "..." button, select the path, and enter the file name. Please, ensure that the path is the same as that previously selected, and the one corresponding to the '.qgz' project file.
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Click OK.
The plugin will begin to process the information. A message bar at the top will indicate the approximate progress of the process.
Once the process of creating the files with the input data is finished, the Hydronia Data Input Program is opened automatically and a dialog window is presented with the model project to run. In this case: 'base.DAT' should already be set.
Then the window with the input parameters of RiverFlow2D is presented, as shown in the image below:
Enter 5 hours for the Simulation time and click on the Storm Drain EPA-SWMM panel. Enter for the N1 node CD = 0 since we don't want exchange with that inflow node to the conduit.
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Click [Save .LWSMM] and overwrite the existing file, for this tutorial the filename will be the name of the project when it was exported with the '.lwsmm' extension.
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Click the Run RiverFlow2D button to run the model. The model will show a window reporting on the model progress.
When the run finishes, close the window and you can import results back in QGIS to prepare maps and animations. An example of the maximum depths is shown below:
This concludes the Urban Drainage using RiverFlow2D and EPA-SWMM tutorial.