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NOAA-OWP / inundation-mapping

Flood inundation mapping and evaluation software configured to work with U.S. National Water Model.
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[13pt] Subdivision routine not being applied to certain catchments #1257

Open CarsonPruitt-NOAA opened 2 months ago

CarsonPruitt-NOAA commented 2 months ago

This is at pinn4 in HUC 02030103. It caught my eye because of the large discrepancy in extents from one catchment to the next and I noticed that the subdivision routine wasn't being applied in all of these catchments. That may be a contributing factor, but we should also make sure there's nothing else going on. The flow during this event peaked at minor, which is 19ft and around 2700 cfs. Stage-based CatFIM is available at this site, but also looks a little weird in this area.

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CarsonPruitt-NOAA commented 2 months ago

In v4.5.2.11, HydroID 10680016 appeared to not have sucessfully run the subdivision.

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RobHanna-NOAA commented 2 months ago

We still have the logs we can check on this huc

mluck commented 2 months ago

After discussing with @CarsonPruitt-NOAA, it looks like there are potentially 3 things going on here:

  1. Subdivision is not applied in some reaches in fim_4_5_2_11 because Stage_bankfull in the SRC table is empty. This seems to have been addressed in subsequent FIM versions because Stage_bankfull is populated and subdivision is applied in those same reaches starting with fim_4_5_4_4.

  2. The channel doesn't represent the lowest part of the DEM or REM, and there are lower areas of channel upstream that are not continued downstream. We will try to re-download a fresh DEM and see if this issue has been fixed. If so, we will re-download all of our DEMs. The DEM (gray scale) and REM (color scale) both show this in relation to the channel (dashed line); streamflow is from bottom to top. image image

  3. It looks like spatial calibration is being applied well beyond the calibration domain and is having a large effect on the SRC (with adjustment factors as low as ~0.05).

mluck commented 2 months ago

There is a difference between the old DEM and one that was downloaded today. The new one appears to have a better representation of the channel. Here's an image of the new DEM and the difference (new - old). image image