Urban Flood Risk Model Outputs

Hello there,

I am currently trying to use the urban flood risk model to evaluate potential damage costs to built infrastructure and run-off retention. I ran the model using the sample dataset Invest provides alongside an arbitrary value of 17 mm for rainfall depth however I am having some trouble interpreting and locating the outputs.

I am trying to find the values to generate a runoff retention map (m^3) like the following:

.There seems to be a database file but there are only 5 values inside that correspond to the flood risk service outputs not the rest of the runoff retention values. Where are the other values found to generate this map? Are they post-processed or QGIS is able to read it?

On another note, I tried to open the runoff_retention_m3 raster in QGIS hoping to get a map with the classified runoff retention values.

I have included a zip file to the model’s outputs that I am getting. invest_test_outputs.zip (198.9 KB)

Any help on where the rest of those runoff retention values are or post-processing insights would be appreciated!

Thanks,

Rachel

Hi @rxchelzhxng,
The output folder that you uploaded has everything I would expect (except for the log file, did you take that out?) The files Runoff_retention_finished.tif (unitless index), Runoff_retention_finished_m3.tif (cubic meters), and Q_mm_finished.tif (millimeters) correspond to the runoff retention map on the left of that image. The flood_risk_service_finished.shp file has the summaries per sub-watershed (the sample watersheds data watersheds.gpkg only has one watershed, so there is only one shape in the output). Please see the user’s guide for reference.

Let me know if that helps. Are you not able to open the files in QGIS?

Hi,

I am able to open the files in QGIS however I am not seeing as many output runoff retention values as the image on the left. Although that could just be because of the sample data. To make sure we are interpreting the same image, I’ve included a screenshot of what I see in QGIS for the runoff_retention_finished_m3.tif.

As for the log file, I don’t have one that is generated when I run the model. Do you know what could be the issue to that?

Thanks once again!

I also did want to ask where the geographical region is for the sample dataset that is provided? If there is a geoJSON file with the coordinates of the boundary/land use land cover that would be great.

Hi @rxchelzhxng,
The sample data covers a different area than the maps in the original image you attached, so it’s going to look different. Do you mean that there’s less variation in the runoff retention values?

The sample dataset location is near San Mateo, California. You can check this by overlaying it with a global map in QGIS. If you want a vector polygon outlining the LULC map area, there are tools in your GIS software to do that. For example in QGIS, Processing > Layer tools > Extract layer extent.

Hi,

Yes there is less variation but that could just be because of the sample dataset and rainfall depth I specified.

I did try to extract the layer extent and it worked, thank you.

As for another question I had, was the image on the left from my initial post processed in QGIS to only show a blue band? Or was there additional post-processing done in Python?

Thanks,

Rachel

Hi @rxchelzhxng,
Yes, the sample dataset is relatively simple. There is only one soil group in the area and only a few different curve number values for the landcover codes in the area. So there are relatively few different values that will be in the result.

I’m not quite sure what you mean about the blue band, the model outputs only have one band to start with. It looks like the runoff_retention_m3 output. I don’t think any post processing was done aside from coloring it and adding the key.

Okay that clears things up, thank you!

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