UK EA benchmark 4 (Water Module): Difference between revisions

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This page contains the test case 3 of the UK benchmark named ''Test 4 – Speed of flood propagation over an extended floodplain'' as well as its result generated by the Water Module in the Tygron Platform.__NOTOC__
This [[Water Module benchmarks|benchmark]] performs the UK EA benchmark '''Test 4 – Speed of flood propagation over an extended floodplain''' using the [[Water Module]] of the {{software}}.__NOTOC__


''The objective of the test is to assess the package’s ability to simulate the celerity of propagation of a flood wave and predict transient velocities and depths at the leading edge of the advancing flood front. It is relevant to fluvial and coastal inundation resulting from breached embankments.''
The objective of this benchmark is to assess the package’s ability to simulate the celerity of propagation of a flood wave and predict transient velocities and depths at the leading edge of the advancing flood front. It is relevant to fluvial and coastal inundation resulting from breached embankments.<ref name="Néelz"/>


A copy of this test project is made available to everyone, providing hands-on insights to those interested. The project can be found on the LTS server under the name '''UKEA benchmark 4'''. This is covered in more detail in [[UK EA benchmark 4 (Water Module)#Public test project|this]] section.
[[File:UK_test_4.gif|left|Animation of the test result for case 4, generated by the {{software}}. Map dimensions = 1,000 x 2,000 m. Grid-cell size = 5 m.]]
{{clear}}
==Description==
==Description==
''This test is designed to simulate the rate of flood wave propagation over a 1000m x 2000m floodplain following a defence failure, Figure (a). The floodplain surface is horizontal, at elevation 0m. One inflow boundary condition will be used, simulating the failure of an embankment by breaching or overtopping, with a peak flow of 20 m 3 /s and time base of ~ 6 hours. The boundary condition is applied along a 20m line in the middle of the western side of the floodplain.''
This test is designed to simulate the rate of flood wave propagation over a 1,000 x 2,000 m floodplain following a defense failure (Fig. (a)). The floodplain surface is horizontal, at datum (= 0 m). One inflow boundary condition will be used, simulating the failure of an embankment by breaching or overtopping, with a peak flow of 20 m<sup>3</sup>/s and time base of ~6 h. The boundary condition is applied along a 20-m line in the middle of the western side of the floodplain.<ref name="Néelz"/>


[[File:topdown_case4_ukbm.png|thumb|left|Figure (a): Modeled domain, showing the location of the 20m inflow, 6 output points, and possible 10 cm and 20 cm contour lines at time 1 hour (dashed) and 3 hours solid).]]
[[File:topdown_case4_ukbm.png|thumb|left|Figure (a): Modeled domain and the locations of the 20-m line of inflow, 6 output points, and the aimed for 0.1-m and 0.2-m contour lines at t = 1 h (dashed) and t = 3 h (solid), respectively.]]
[[File:hydrograph_case4_ukbm.png|thumb|left|Figure (b): Hydrograph applied as inflow boundary condition.]]
[[File:hydrograph_case4_ukbm.png|thumb|center|Figure (b): Hydrograph applied as inflow boundary condition.]]
<br style="clear:both">
<br style="clear:both">


==Boundary and initial condition==
==Boundary and initial condition==
*''Inflow boundary condition as shown in Figure (b). Table provided as part of dataset.''
* Inflow boundary condition as shown in Fig. (b)
*''All other boundaries are closed.''
* All other boundaries are closed
*''Initial condition: Dry bed.''
* Initial condition: dry bed


==Parameter values==
==Parameter values==
*''Manning’s n: 0.05 (uniform)''
* Manning’s ''n'': 0.05 (uniform)
*''Model grid resolution: 5m (or ~80000 nodes in the area modelled)''
* Model grid resolution (m): 5 (or ~80,000 nodes in the area modeled)
*''Time of end: the model is to be run until time t = 5 hours (if an alternative end time is used run times must be reported for t=5 hours)''
* Simulated time (h): 5


==Required output==
==Required output==
* ''Software package used: version and numerical scheme.''
{| class=wikitable align=right
* ''Specification of hardware used to undertake the simulation: processor type and speed,RAM.''
* ''Minimum recommended hardware specification for a simulation of this type.''
* ''Time increment used, grid resolution (or number of nodes in area modelled) and total simulation time to specified time of end.''
* ''Raster grids (or TIN) at the model resolution consisting of:''
** ''Depths at times 30mins, 1 hour, 2 hours 3 hours, 4 hours.''
** ''Velocities (scalar) at times 30mins, 1 hour, 2 hours 3 hours, 4 hours.''
* ''Plots of velocity and water elevation versus time (suggested output frequency 20s) at the six locations represented in Figure (a) and provided as part of dataset.''
: These locations are:
{|class=wikitable
!Point ID
!Point ID
!X
!X
Line 37: Line 32:
|1
|1
|50
|50
|1000
|1,000
|-
|-
|2
|2
|100
|100
|1000
|1,000
|-
|-
|3
|3
|200
|200
|1000
|1,000
|-
|-
|4
|4
|300
|300
|1000
|1,000
|-
|-
|5
|5
|300
|400
|1000
|1,000
|-
|-
|6
|6
|300
|300
|1300
|1,300
|}
|}
* Software package used: version and numerical scheme
* Specification of hardware used to undertake the simulation: processor type and speed, RAM
* Minimum recommended hardware specification for a simulation of this type
* Time increment used, grid resolution (or number of nodes in area modeled) and total simulation time to specified time of end
* Raster grids (or TIN) at the model resolution consisting of:
** Depths and at t = 30 min, 1 h, 2 h, 3 h and 4 h
** Velocities (scalar) at t = 30 min, 1 h, 2 h, 3 h and 4 h
* Plots of velocity and water elevation v. time (suggested output frequency: 20 s) at the 6 locations represented in Fig. (a) and provided as part of dataset


==Dataset content==
==Dataset content==
*''Upstream boundary condition table (inflow vs. time). Filename: Test4BC.csv''
* Upstream boundary condition table (inflow v. time). Filename: ''Test4BC.csv''
*''Location of output points. Filename: Test4Output.csv''
* Location of output points. Filename: ''Test4Output.csv''


''The model geometry is as specified in Section 2. No DEM is provided as the ground
The model geometry is as specified in Section 2. No DEM is provided, as the surface elevation is level at datum (= 0 m).<ref name="Néelz"/>
elevation is uniformly 0.''


==Technical setup==
==Technical setup==
The setup in this case is a flat surface. It does not require the import of a dem file, since all height values are set to 0.
[[File:setup_case4_ukbm.png|thumb|right|x300px|Figure 1. The relative positions of the measurement points used in this test.]]
Other stats:
* Flat surface
* The grid cell size: 5 m.
* Grid-cell size (m): 5
* The area size: 1010x2010, which includes a border of 5 meters and the required domain of 1000m, x 2000m.
* Area size (m): 1,010 x 2,010 (required domain of 1,000 x 2,000 + 5-m border)
* The measurement points have been put on the correct positions, see the image below.
* The measurement points were positioned correctly (see Fig. 1)
[[File:setup_case4_ukbm.png|thumb|left|x300px|Setup of case 4 used by the {{software}}]]<br style="clear:both">
In order to regulate the boundary discharge according the hydrograph (Fig. 2), 2 inlets were implemented. Both inlets occupied one grid cell, one of these located above and the other below the green center line (Fig. 3). The inlets were configured as follows:
In order to regulate the water level according to the water level graph, we used the following setup: Only two inlets are used. These are put on the cells above and below the center line indicated by the green line. Each inlet had its own grid cell. The inlets were configured as:  
* External area (m<sup>2</sup>): 1,000,000,000 (default)
* External area (m2): 1 000 000 000;
* Water level (m): 1 (default)
* Water level (m): 1;
* Threshold (m): none (default)
* Threshold (m): none;
* Inlet Q (m):
* Inlet Q (m):
[[File:inletq_case4_ukbm.png|thumb|left|x300px|Inlet influx graph used by the {{software}}]]<br style="clear:both">
[[File:inletq_case4_ukbm.png|thumb|left|x300px|Figure 2. Hydrograph displaying the implemented individual and combined inlet fluxes.]]<br style="clear:both">
* Inlet locations:
[[File:inletpositions_case4_ukbm.png|thumb|left|x300px|Figure 3. Positions of the inlet cells (red squares) with respect to the center line of measurement (green).]]<br style="clear:both">
[[File:inletpositions_case4_ukbm.png|thumb|left|x300px|Inlet positions.]]<br style="clear:both">


==Results==
==Results==
*Software package used: {{software}}
===Stats===
*Numerical scheme: FV (Kurganov, Bollerman, Horvath)*
* Software package used: {{software}}
*Specification of hardware used to undertake the simulation:  
* Numerical scheme: [[Surface flow formula (Water Overlay)|FV (Kurganov, Bollerman, Horvath)]]
** Processor: Intel Xeon @2.10GHz x 8,
* Specification of hardware used to undertake the simulation:  
** RAM 62.8 GiB,
** Processor: Intel Xeon @2.10GHz x 8
** GPU: 2x NVidia 1080
** RAM (GB): 62.8
** GPU: 2x NVidia 1,080
** Operating system: Linux 4.13
** Operating system: Linux 4.13
*Time increment used: adaptive:
* Time increment used: adaptive
*Grid resolution: 5 m.
* Grid resolution (m): 5
*Simulation time: 29 seconds for 900 timeframes
* Calculation time (s): 29 (for 900 timeframes)
*Inlet q M3: 283723.8 m<sup>3</sup>
* Object flow (m<sup>3</sup>/s): 283,723.8
*Remaining volume water: 283606.9 m<sup>3</sup>
* Remaining water volume (m<sup>3</sup>/s): 283,606.9


===Raster grids (or TIN) at the model resolution consisting of waterlevels and velocities===
===Raster grids (or TIN) at the model resolution for water level and flow velocity===
====Contours====
====Contours of inundation extent (>= 0.15 m depth)====
<ul>
<ul>
<li style="display:inline-block">[[File:contour_30m_case4_ukbm.png|thumb|left|x300px|Contour 30 minutes.]]</li>
<li style="display:inline-block">[[File:contour_30m_case4_ukbm.png|thumb|left|x300px|t = 30 min]]</li>
<li style="display:inline-block">[[File:contour_1h_case4_ukbm.png|thumb|left|x300px|Contour 1 hour.]]</li>
<li style="display:inline-block">[[File:contour_1h_case4_ukbm.png|thumb|left|x300px|t = 1 h]]</li>
<li style="display:inline-block">[[File:contour_2h_case4_ukbm.png|thumb|left|x300px|Contour 2 hours.]]</li>
<li style="display:inline-block">[[File:contour_2h_case4_ukbm.png|thumb|left|x300px|t = 2 h]]</li>
<li style="display:inline-block">[[File:contour_3h_case4_ukbm.png|thumb|left|x300px|Contour 3 hours.]]</li>
<li style="display:inline-block">[[File:contour_3h_case4_ukbm.png|thumb|left|x300px|t = 3 h]]</li>
<li style="display:inline-block">[[File:contour_4h_case4_ukbm.png|thumb|left|x300px|Contour 4 hours.]]</li><br>
<li style="display:inline-block">[[File:contour_4h_case4_ukbm.png|thumb|left|x300px|t = 4 h]]</li><br>
<li style="display:inline-block">[[File:contour_others_case4_ukbm.png|thumb|left|x300px|Contour 1 and 3 hours of others.]]</li>
<li style="display:inline-block">[[File:contour_others_case4_ukbm.png|thumb|left|x300px|Results of other packages for t = 1 h and 3 h.]]</li>
</ul>
</ul>


==Cross sections==
====Cross sections====
<ul>
<ul>
<li style="display:inline-block">[[File:crosssection_waterlevel_1h_case4_ukbm.png|thumb|left|x300px|Waterlevel cross-section after 1 hour.]]</li>
<li style="display:inline-block">[[File:crosssection_waterlevel_1h_case4_ukbm.png|thumb|left|x300px|Water level across center line at t = 1 h.]]</li>
<li style="display:inline-block">[[File:crosssection_waterlevel_others_1h_case4_ukbm.png|thumb|left|x300px|Waterlevel cross-section others after 1 hour.]]</li><br>
<li style="display:inline-block">[[File:crosssection_waterlevel_others_1h_case4_ukbm.png|thumb|left|x300px|Water level across center line at t = 1 h for other packages.]]</li><br>
<li style="display:inline-block">[[File:crosssection_velocity_1h_case4_ukbm.png|thumb|left|x300px|Velocity cross-section after 1 hour.]]</li>
<li style="display:inline-block">[[File:crosssection_velocity_1h_case4_ukbm.png|thumb|left|x300px|Flow velocity across center line at t = 1 h.]]</li>
<li style="display:inline-block">[[File:crosssection_velocity_others_1h_case4_ukbm.png|thumb|left|x300px|Velocity cross-section others after 1 hour.]]</li>
<li style="display:inline-block">[[File:crosssection_velocity_others_1h_case4_ukbm.png|thumb|left|x300px|Flow velocity across center line at t = 1 h for other packages.]]</li>
</ul>
</ul>


===Plots of velocity and water elevation versus time===
===Time series of water level and flow velocity===
<ul>
<ul>
<li style="display:inline-block">[[File:waterlevel_p1_case4_ukbm.png|thumb|left|x300px|Waterlevel point 1.]]</li>
<li style="display:inline-block">[[File:waterlevel_p1_case4_ukbm.png|thumb|left|x300px|Water level at Point 1.]]</li>
<li style="display:inline-block">[[File:waterlevel_others_p1_case4_ukbm.png|thumb|left|x300px|Waterlevel point 1 others.]]</li><br>
<li style="display:inline-block">[[File:waterlevel_others_p1_case4_ukbm.png|thumb|left|x300px|Water level at Point 1 (others).]]</li><br>
<li style="display:inline-block">[[File:velocity_p1_case4_ukbm.png|thumb|left|x300px|Velocity point 1.]]</li>
<li style="display:inline-block">[[File:velocity_p1_case4_ukbm.png|thumb|left|x300px|Flow velocity at Point 1.]]</li>
<li style="display:inline-block">[[File:velocity_others_p1_case4_ukbm.png|thumb|left|x300px|Velocity point 1 others.]]</li><br>
<li style="display:inline-block">[[File:velocity_others_p1_case4_ukbm.png|thumb|left|x300px|Flow velocity at Point 1 (others).]]</li><br>
<li style="display:inline-block">[[File:waterlevel_p2_case4_ukbm.png|thumb|left|x300px|Waterlevel point 2.]]</li><br>
<li style="display:inline-block">[[File:waterlevel_p2_case4_ukbm.png|thumb|left|x300px|Water level at Point 2.]]</li><br>
<li style="display:inline-block">[[File:velocity_p2_case4_ukbm.png|thumb|left|x300px|Velocity point 2.]]</li><br>
<li style="display:inline-block">[[File:velocity_p2_case4_ukbm.png|thumb|left|x300px|Flow velocity at Point 2.]]</li><br>
<li style="display:inline-block">[[File:waterlevel_p3_case4_ukbm.png|thumb|left|x300px|Waterlevel point 3.]]</li>
<li style="display:inline-block">[[File:waterlevel_p3_case4_ukbm.png|thumb|left|x300px|Water level at Point 3.]]</li>
<li style="display:inline-block">[[File:waterlevel_others_p3_case4_ukbm.png|thumb|left|x300px|Waterlevel point 3 others.]]</li><br>
<li style="display:inline-block">[[File:waterlevel_others_p3_case4_ukbm.png|thumb|left|x300px|Water level at Point 3 (others).]]</li><br>
<li style="display:inline-block">[[File:velocity_p3_case4_ukbm.png|thumb|left|x300px|Velocity point 3.]]</li>
<li style="display:inline-block">[[File:velocity_p3_case4_ukbm.png|thumb|left|x300px|Flow velocity at Point 3.]]</li>
<li style="display:inline-block">[[File:velocity_others_p3_case4_ukbm.png|thumb|left|x300px|Velocity point 3 others.]]</li><br>
<li style="display:inline-block">[[File:velocity_others_p3_case4_ukbm.png|thumb|left|x300px|Flow velocity at Point 3 (others).]]</li><br>
<li style="display:inline-block">[[File:waterlevel_p4_case4_ukbm.png|thumb|left|x300px|Waterlevel point 4.]]</li><br>
<li style="display:inline-block">[[File:waterlevel_p4_case4_ukbm.png|thumb|left|x300px|Water level at Point 4.]]</li><br>
<li style="display:inline-block">[[File:velocity_p4_case4_ukbm.png|thumb|left|x300px|Velocity point 4.]]</li><br>
<li style="display:inline-block">[[File:velocity_p4_case4_ukbm.png|thumb|left|x300px|Flow velocity at Point 4.]]</li><br>
<li style="display:inline-block">[[File:waterlevel_p5_case4_ukbm.png|thumb|left|x300px|Waterlevel point 5.]]</li>
<li style="display:inline-block">[[File:waterlevel_p5_case4_ukbm.png|thumb|left|x300px|Water level at Point 5.]]</li>
<li style="display:inline-block">[[File:waterlevel_others_p5_case4_ukbm.png|thumb|left|x300px|Waterlevel point 5 others.]]</li><br>
<li style="display:inline-block">[[File:waterlevel_others_p5_case4_ukbm.png|thumb|left|x300px|Water level at Point 5 (others).]]</li><br>
<li style="display:inline-block">[[File:velocity_p5_case4_ukbm.png|thumb|left|x300px|Velocity point 5.]]</li>
<li style="display:inline-block">[[File:velocity_p5_case4_ukbm.png|thumb|left|x300px|Flow velocity at Point 5.]]</li>
<li style="display:inline-block">[[File:velocity_others_p5_case4_ukbm.png|thumb|left|x300px|Velocity point 5 others.]]</li><br>
<li style="display:inline-block">[[File:velocity_others_p5_case4_ukbm.png|thumb|left|x300px|Flow velocity at Point 5 (others).]]</li><br>
<li style="display:inline-block">[[File:waterlevel_p6_case4_ukbm.png|thumb|left|x300px|Waterlevel point 6.]]</li>
<li style="display:inline-block">[[File:Waterlevel_p6_case4_ukbm_new.png|thumb|left|x300px|Water level at Point 6.]]</li>
<li style="display:inline-block">[[File:waterlevel_others_p6_case4_ukbm.png|thumb|left|x300px|Waterlevel point 6 others.]]</li><br>
<li style="display:inline-block">[[File:waterlevel_others_p6_case4_ukbm.png|thumb|left|x300px|Water level at Point 6 (others).]]</li><br>
<li style="display:inline-block">[[File:velocity_p6_case4_ukbm.png|thumb|left|x300px|Velocity point 6.]]</li>
<li style="display:inline-block">[[File:velocity_p6_case4_ukbm.png|thumb|left|x300px|Flow velocity at Point 6.]]</li>
<li style="display:inline-block">[[File:velocity_others_p6_case4_ukbm.png|thumb|left|x300px|Velocity point 6 others.]]</li>
<li style="display:inline-block">[[File:velocity_others_p6_case4_ukbm.png|thumb|left|x300px|Flow velocity at Point 6 (others).]]</li>
</ul>
</ul>
===Notes===
* Test results of Point 2 and 4 for the other packages were not provided.
* The stepwise behavior seen in the velocity profiles can be related to the definition of the inlet inflow, which is also stepwise.
==Public test project==
A copy of this test project is made available to everyone, providing hands-on insights to those interested. The project can be found on the LTS server under the name '''UKEA benchmark 4'''. In this project the discussed benchmark test is reproduced, based on a map size of 1,010 m x 2,010 m to compensate for the 5-m border cells. These special map dimensions are generally not selectable in the [[New Project Wizard]] and require configuration through the [[API]].
===Measurement points===
The locations of the measurement points are:
{| class=wikitable
!Point ID
!X
!Y
|-
|1
|55
| -1,005
|-
|2
|105
| -1,005
|-
|3
|205
| -1,005
|-
|4
|305
| -1,005
|-
|5
|405
| -1,005
|-
|6
|305
| -705
|}
Note that the coordinate system in this project differs from the one used during the actual benchmark testing as shown in Fig. (a). For the above listed points the center (0,0) is located at the top-left corner instead of the bottom-left, hence will the bottom-right corner have coordinates (1,010;-2,010).
===Water level relative to datum===
The time series of a fixed measurement point can be obtained as follows:
{{Editor steps|title=obtain water levels relative to datum|Go to the flooding overlay "Water Level (m)".|Select the measuring tool.|From the ''Saved'' dropdown choose your point of interest.|From the ''Base'' dropdown select "Surface Elevation (m)".|Make sure the ''Sum'' box is checked.|Select ''Fit Graph'' to zoom in on the relevant part of the plot.}}
===Settings & output===
{|class="wikitable" style="display: inline-table;"
!Setting
!Unit
!Value
|-
|GRAVITY
|m/s<sup>2</sup>
|9.80665
|-
|QUAD_CELL
|''Boolean''
|0
|-
|Open land
|m<sup>2</sup>
|14,496,160
|-
|Surface elevation
|m
|1
|-
|Manning's ''n''
|s/(m<sup>1/3</sup>)
|0.05
|-
|Calc. pref.
|
|Accuracy
|}
{|class="wikitable" style="display: inline-table;"
!Output
!Unit
!Value
|-
|Total volume
|m<sup>3</sup>
|282,057
|-
|Water balance error
|m<sup>3</sup>
| -159 (0%)
|-
|Single cells
|
|81,204
|-
|Calc. steps
|
|49,008
|-
|Calc. time
|s
|22
|}
Note that these output values may deviate slightly from those of the initial testing phase (i.e. not the public test project), since there is a substantial time gap between when the two projects were set up, during which several changes have been made to the engine.
==References==
<references>
<ref name="Néelz">Néelz, S., & Pender, G. (2013). Benchmarking the latest generation of 2D hydraulic modelling packages. Report: SC120002. Environment Agency, Horison House, Deanery Road, Bristol, BS1 9AH. ISBN: 978-1-84911-306-9. Retrieved from: https://www.gov.uk/government/publications/benchmarking-the-latest-generation-of-2d-hydraulic-flood-modelling-packages </ref>
</references>
[[Category:Benchmarks]]
{{Water Module buttons}}

Latest revision as of 15:14, 5 March 2024

This benchmark performs the UK EA benchmark Test 4 – Speed of flood propagation over an extended floodplain using the Water Module of the Tygron Platform.

The objective of this benchmark is to assess the package’s ability to simulate the celerity of propagation of a flood wave and predict transient velocities and depths at the leading edge of the advancing flood front. It is relevant to fluvial and coastal inundation resulting from breached embankments.[1]

A copy of this test project is made available to everyone, providing hands-on insights to those interested. The project can be found on the LTS server under the name UKEA benchmark 4. This is covered in more detail in this section.

Animation of the test result for case 4, generated by the Tygron Platform. Map dimensions = 1,000 x 2,000 m. Grid-cell size = 5 m.

Description

This test is designed to simulate the rate of flood wave propagation over a 1,000 x 2,000 m floodplain following a defense failure (Fig. (a)). The floodplain surface is horizontal, at datum (= 0 m). One inflow boundary condition will be used, simulating the failure of an embankment by breaching or overtopping, with a peak flow of 20 m3/s and time base of ~6 h. The boundary condition is applied along a 20-m line in the middle of the western side of the floodplain.[1]

Figure (a): Modeled domain and the locations of the 20-m line of inflow, 6 output points, and the aimed for 0.1-m and 0.2-m contour lines at t = 1 h (dashed) and t = 3 h (solid), respectively.
Figure (b): Hydrograph applied as inflow boundary condition.


Boundary and initial condition

  • Inflow boundary condition as shown in Fig. (b)
  • All other boundaries are closed
  • Initial condition: dry bed

Parameter values

  • Manning’s n: 0.05 (uniform)
  • Model grid resolution (m): 5 (or ~80,000 nodes in the area modeled)
  • Simulated time (h): 5

Required output

Point ID X Y
1 50 1,000
2 100 1,000
3 200 1,000
4 300 1,000
5 400 1,000
6 300 1,300
  • Software package used: version and numerical scheme
  • Specification of hardware used to undertake the simulation: processor type and speed, RAM
  • Minimum recommended hardware specification for a simulation of this type
  • Time increment used, grid resolution (or number of nodes in area modeled) and total simulation time to specified time of end
  • Raster grids (or TIN) at the model resolution consisting of:
    • Depths and at t = 30 min, 1 h, 2 h, 3 h and 4 h
    • Velocities (scalar) at t = 30 min, 1 h, 2 h, 3 h and 4 h
  • Plots of velocity and water elevation v. time (suggested output frequency: 20 s) at the 6 locations represented in Fig. (a) and provided as part of dataset

Dataset content

  • Upstream boundary condition table (inflow v. time). Filename: Test4BC.csv
  • Location of output points. Filename: Test4Output.csv

The model geometry is as specified in Section 2. No DEM is provided, as the surface elevation is level at datum (= 0 m).[1]

Technical setup

Figure 1. The relative positions of the measurement points used in this test.
  • Flat surface
  • Grid-cell size (m): 5
  • Area size (m): 1,010 x 2,010 (required domain of 1,000 x 2,000 + 5-m border)
  • The measurement points were positioned correctly (see Fig. 1)

In order to regulate the boundary discharge according the hydrograph (Fig. 2), 2 inlets were implemented. Both inlets occupied one grid cell, one of these located above and the other below the green center line (Fig. 3). The inlets were configured as follows:

  • External area (m2): 1,000,000,000 (default)
  • Water level (m): 1 (default)
  • Threshold (m): none (default)
  • Inlet Q (m):
Figure 2. Hydrograph displaying the implemented individual and combined inlet fluxes.


Figure 3. Positions of the inlet cells (red squares) with respect to the center line of measurement (green).


Results

Stats

  • Software package used: Tygron Platform
  • Numerical scheme: FV (Kurganov, Bollerman, Horvath)
  • Specification of hardware used to undertake the simulation:
    • Processor: Intel Xeon @2.10GHz x 8
    • RAM (GB): 62.8
    • GPU: 2x NVidia 1,080
    • Operating system: Linux 4.13
  • Time increment used: adaptive
  • Grid resolution (m): 5
  • Calculation time (s): 29 (for 900 timeframes)
  • Object flow (m3/s): 283,723.8
  • Remaining water volume (m3/s): 283,606.9

Raster grids (or TIN) at the model resolution for water level and flow velocity

Contours of inundation extent (>= 0.15 m depth)

  • t = 30 min
  • t = 1 h
  • t = 2 h
  • t = 3 h
  • t = 4 h

  • Results of other packages for t = 1 h and 3 h.

Cross sections

  • Water level across center line at t = 1 h.
  • Water level across center line at t = 1 h for other packages.

  • Flow velocity across center line at t = 1 h.
  • Flow velocity across center line at t = 1 h for other packages.

Time series of water level and flow velocity

  • Water level at Point 1.
  • Water level at Point 1 (others).

  • Flow velocity at Point 1.
  • Flow velocity at Point 1 (others).

  • Water level at Point 2.

  • Flow velocity at Point 2.

  • Water level at Point 3.
  • Water level at Point 3 (others).

  • Flow velocity at Point 3.
  • Flow velocity at Point 3 (others).

  • Water level at Point 4.

  • Flow velocity at Point 4.

  • Water level at Point 5.
  • Water level at Point 5 (others).

  • Flow velocity at Point 5.
  • Flow velocity at Point 5 (others).

  • Water level at Point 6.
  • Water level at Point 6 (others).

  • Flow velocity at Point 6.
  • Flow velocity at Point 6 (others).

Notes

  • Test results of Point 2 and 4 for the other packages were not provided.
  • The stepwise behavior seen in the velocity profiles can be related to the definition of the inlet inflow, which is also stepwise.

Public test project

A copy of this test project is made available to everyone, providing hands-on insights to those interested. The project can be found on the LTS server under the name UKEA benchmark 4. In this project the discussed benchmark test is reproduced, based on a map size of 1,010 m x 2,010 m to compensate for the 5-m border cells. These special map dimensions are generally not selectable in the New Project Wizard and require configuration through the API.

Measurement points

The locations of the measurement points are:

Point ID X Y
1 55 -1,005
2 105 -1,005
3 205 -1,005
4 305 -1,005
5 405 -1,005
6 305 -705

Note that the coordinate system in this project differs from the one used during the actual benchmark testing as shown in Fig. (a). For the above listed points the center (0,0) is located at the top-left corner instead of the bottom-left, hence will the bottom-right corner have coordinates (1,010;-2,010).

Water level relative to datum

The time series of a fixed measurement point can be obtained as follows:

How to obtain water levels relative to datum:
  1. Go to the flooding overlay "Water Level (m)".
  2. Select the measuring tool.
  3. From the Saved dropdown choose your point of interest.
  4. From the Base dropdown select "Surface Elevation (m)".
  5. Make sure the Sum box is checked.
  6. Select Fit Graph to zoom in on the relevant part of the plot.

Settings & output

Setting Unit Value
GRAVITY m/s2 9.80665
QUAD_CELL Boolean 0
Open land m2 14,496,160
Surface elevation m 1
Manning's n s/(m1/3) 0.05
Calc. pref. Accuracy
Output Unit Value
Total volume m3 282,057
Water balance error m3 -159 (0%)
Single cells 81,204
Calc. steps 49,008
Calc. time s 22

Note that these output values may deviate slightly from those of the initial testing phase (i.e. not the public test project), since there is a substantial time gap between when the two projects were set up, during which several changes have been made to the engine.

References

  1. ↑ 1.0 1.1 1.2 Néelz, S., & Pender, G. (2013). Benchmarking the latest generation of 2D hydraulic modelling packages. Report: SC120002. Environment Agency, Horison House, Deanery Road, Bristol, BS1 9AH. ISBN: 978-1-84911-306-9. Retrieved from: https://www.gov.uk/government/publications/benchmarking-the-latest-generation-of-2d-hydraulic-flood-modelling-packages
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