[21pt] Georeferenced Impact statement calibration

[CarsonPruitt-NOAA]

1. Identify a site with some polygons

2. Sample the REM values under each polygon

3. Make stage "windows" for each impact stage, e.g.:
   

4. Adjust manning's n to make the SRC go through each stage "window"

Georeferenced impact statements service:
https://noaa.maps.arcgis.com/home/item.html?id=ff3748e1c4064bb6be4a82994681a0fb

[ZahraGhahremani]

[ZahraGhahremani]

In the new workflow, we incorporated all polygons surrounding the catchment. Using the median, 75th percentile, and upper extreme values from each stage window, we calculated a weighted average coefficient for each flood impact category (minor, moderate, and major). These coefficients were then used to derive a median value, which was applied to calculate updated Manning's roughness and recalculate the discharge.
The results are summarized below. The blue curve represents the default FIM (pre-calibration), the green curve shows the calibrated FIM, and the red curve represents the rating curve after calibration using georeferenced impact statements.

HUC 05100101, catchment 15850355

Assigning a higher weight to the median value. Weights: median 0.7, 75th percentile: 0.2, upper extreme: 0.1.

Assigning a higher weight to the 75th percentile. Weights: median 0.1, 75th percentile: 0.7, upper extreme: 0.2

Assigning a higher weight to the upper extreme. Weights: median 0.1, 75th percentile: 0.2, upper extreme: 0.7

[ZahraGhahremani]

This shows the inundation for major flow. The red shade represents the impact statement major polygon.

When we give higher weight to upper extreme hand values, the inundation extent aligns more closely with the impact statement polygons.