56,571
buildings with flood exposure (6.8%)
Total buildings832,102
Mean depth (flooded)3.52 ft
Max depth13.0 ft
Mean damage index0.117
MAPE vs USGS HWMs121.8%
NWM sourceRetro v3.0
Color mode
Legend
344 USGS High Water Marks
Circles = observed HWM locations.
Color = model − observed depth.
■ Red: model under-predicts
■ Green: accurate (±2 ft)
■ Blue: model over-predicts
⊗ Halo: dry miss (model=0)
Circles = observed HWM locations.
Color = model − observed depth.
■ Red: model under-predicts
■ Green: accurate (±2 ft)
■ Blue: model over-predicts
⊗ Halo: dry miss (model=0)
Phase 1 calibration status
Rating curves: Manning's equation with stream-order d_bf caps and W_fp floors (Missouri: 10km). USGS gauge corrections applied (IDW, 85 gauges). Missouri q_scale overridden to 1.0 (NWM accuracy 99%). Structural MAPE floor ~120% — per-reach OWP FIM SRCs needed for production accuracy.
Rating curves: Manning's equation with stream-order d_bf caps and W_fp floors (Missouri: 10km). USGS gauge corrections applied (IDW, 85 gauges). Missouri q_scale overridden to 1.0 (NWM accuracy 99%). Structural MAPE floor ~120% — per-reach OWP FIM SRCs needed for production accuracy.