FMA Challenge 3: Difference between revisions
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*Understanding the Green and Ampt infiltration method and USDR soil types.<br>
*[https://www.tuflow.com/Download/TUFLOW/Demo_Models/FMA_Challenge_Model_3_QGIS.zip QGIS Data Download]
*[https://www.tuflow.com/Download/TUFLOW/Demo_Models/FMA_Challenge_Model_3_Mapinfo.zip MapInfo Data Download]
*[https://www.tuflow.com/Download/TUFLOW/Demo_Models/FMA_Challenge_Model_3_ArcGIS.zip ArcGIS Data Download]
=Relevant Tutorials=
Other tutorials that are relevant to this challenge that may help refresh your memory are as follows:<br>
*1D-2D Linking - <u>[[
*1D Nested Channel - <u>[[
*Running
*Running Events - <u>[[Tutorial_M09|Tutorial Module 09]]</u>
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To check these Manning's 'n' assumptions, a sensitivity testing was completed on the in-bank roughness and is detailed further in the following sections.
==Boundary Conditions==
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[[File:FMA3_3.jpg|600px]]
==Levee Overtopping Assessment==
To assess the timing and location of where levee banks were overtopped, the TGC was setup with the evacuation route command:<br> <font color="blue"><tt>Read GIS Z Shape Route </tt></font> <font color="red"><tt>==</tt></font> shp\2d_zshr_T3_levees_001_L.shp | shp\2d_zsh_T3_levees_001_P.shp.<br>
Via review of the RC Map Output Data Type and the _RCP output point layer we can identify sections of the levee where a breach has occured (refer below).<br>
[[File:FMA3_6.jpg|600px]]
==Sensitivity Creek Manning's n Test (Scenario 100ft n0.1)==
As discussed in the Manning’s n table above, the main creek n value of 0.20 is considered very high, especially in the lower reaches of the study area. A sensitivity analysis was carried out by lowering all the Manning’s n values in the main channel (
The image below shows the flood depths and extent for the two non-infiltration simulations at 100ft resolution (left with channel 'n' = 0.2, right with channel 'n' = 0.1). Some significant deviations in flood extent can be observed,
[[File:FMA3_3.jpg|600px]][[File:FMA3_4.jpg|600px]]<br>
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[[File:FMA3_7.jpg|600px]]
The 100ft and 200ft simulations were re-run with Green-Ampt infiltration switched on. The resulting peak flood depths map for the 100ft simulation is shown in the image below (right) whilst the 100ft without infiltration is provided on the right. As can be seen, the extent of inundation is significantly reduced with floodwaters infiltrating before reaching the model extents or returning to the main channel.
The mass balance reporting from TUFLOW indicates over half (58%) of the water infiltrates into the ground during the 171 hour simulation. This reduction in volume can also be observed via the “100ft GA” flow hydrograph show above.
[[File:FMA3_3.jpg|600px]][[File:FMA3_8.jpg|600px]]
=Conclusion=
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In this challenge, we explored typical non-urban stream of the California Central Valley, with scenarios of various infiltration and flood levees adopted. From this, we gained a better understanding of the influence of flood levees on surface water behaviour, understanding of the Green Ampt infiltration method and USDR soil types, and a better understanding of nested 1D/2D models.
Congratulations on finishing
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