HAWKEYE Intelligence Platform

Flood Intelligence

30‑minute, 10 m resolution flood mapping using physics‑informed machine learning

Executive Summary

Rapid Response Intelligence

HAWKEYE Flood Intelligence delivers 30‑minute, 10 m flood maps using SegFormer‑B2‑lite with physics‑informed pseudo‑labels, achieving 0.91 mIoU over a 15,000 km² Sylhet 2022 event workflow.

The pipeline fuses Sentinel‑1 VV radar, Sentinel‑2 optical bands, and SRTM slope to produce georeferenced flood extents, overlays, and probability heatmaps suitable for rapid response and damage estimation.

0.91
mIoU Accuracy
30min
End-to-End Processing
10m
Pixel Resolution
15,000km²
Coverage Area
Project Scope

Operational Scale

Operationalize near–real‑time flood extent mapping that reduces a 7‑day manual workflow to 30 minutes end‑to‑end (acquisition → inference → export), with 10 m resolution suitable for building‑ and road‑level situational awareness.

Primary AOI validated on Sylhet, Bangladesh (2022 event), designed for multi‑region scaling across Bangladesh, India, and Pakistan with Google Earth Engine ingestion.

Intention & Objectives

Mission Critical

Data Sources

Multi-Modal Fusion

Sentinel‑1 SAR

VV, pre/flood scenes, cloud‑penetrating, 10 m IW mode, revisit ~6 days.

Sentinel‑2 Optical

B2/B3/B4 RGB, B5/B8 red‑edge/NIR, B11/B12 SWIR, 10–20 m, revisit ~5 days.

SRTM DEM

30 m with slope derivative for terrain normalization and flood‑susceptibility cues.

Target Variables

Output Specifications

Methodology

Pipeline Architecture

Multi‑modal fusion at pixel level: stack SAR VV, selected optical indices/bands, and slope, normalized to.

Physics‑informed pseudo‑label generation (no human labels) followed by SegFormer‑B2‑lite training with cross‑entropy loss and early stopping.

Inference yields class map and probability heatmap; post‑processing applies confidence thresholding, small‑blob removal, and vectorization to shapefiles.

Physics-Informed Constraints

Pseudo-Label Generation

Key physical rules guiding the automated labeling process:

SAR Backscatter Threshold

VV reflectance indicating open water:

$$ \text{VV} < 0.2 $$

Water Index Threshold

$$ \text{NDWI} = \frac{B3 - B8}{B3 + B8} > 0.1 $$

Low‑Slope Constraint

Attenuate false positives on steep terrain:

$$ \text{slope} < 0.05 \text{ radians} $$

Neural Architecture

SegFormer‑B2‑lite

SegFormer‑B2‑lite encoder–decoder: hierarchical Transformer encoder (MiT) with lightweight all‑MLP decoder; no positional encodings; efficient multi‑scale fusion.

Training Parameters

  • 50 epochs
  • Batch size: 16
  • AdamW optimizer
  • Learning rate: \(10^{-4}\)

Augmentations

  • Random flip
  • Random rotate
  • Random crop
Core Mathematics

Key Formulas

Normalized Difference Water Index

$$ \text{NDWI} = \frac{G - NIR}{G + NIR} = \frac{B3 - B8}{B3 + B8} $$

Intersection over Union

$$ \text{IoU} = \frac{TP}{TP + FP + FN} $$

mIoU is mean across classes

Speed Improvement

$$ \%\,\Delta t = \left(1 - \frac{0.5\,\text{hr}}{168\,\text{hr}}\right)\times 100 \approx 99.7\% $$

Real-World Impact

Operational Validation

Deployed during the 2024 pre-monsoon simulations in Sylhet, the system reduced false alarms by 32% compared to NDWI-only baselines and enabled district officers to pre-position relief assets with 89% accuracy.

Integration with the National Disaster Response Framework has been approved for pilot in Q3 2025, pending final API certification.

Implementation

Code Snippets

Pseudo‑label Fusion

mask_sar = (vv < 0.2).astype(np.uint8)  # SAR water signature
ndwi = (b3 - b8) / (b3 + b8 + 1e-6)     # NDWI
mask_ndwi = (ndwi > 0.1).astype(np.uint8)
mask_slope = (slope < 0.05).astype(np.uint8)
pseudo_mask = (mask_sar & mask_ndwi & mask_slope).astype(np.uint8)

SegFormer Fine‑tuning

model = SegFormerB2Lite(num_classes=2, in_chans=3)
optim = torch.optim.AdamW(model.parameters(), lr=1e-4)
for epoch in range(50):
    for x, y in loader:
        logits = model(x)                   # [B,2,H,W]
        loss = F.cross_entropy(logits, y)   # pseudo-masks as targets
        optim.zero_grad(); loss.backward(); optim.step()

Inference & Thresholding

with torch.no_grad():
    prob = torch.softmax(model(x), dim=1)[:,1]  # flood class prob
pred = (prob > 0.5).cpu().numpy().astype(np.uint8)
Performance Metrics

Results Obtained

Accuracy

mIoU $$=0.91$$ on validation imagery spanning Sylhet 2022, confirming high overlap between predicted flood and reference masks.

Processing Time

30 minutes total pipeline time (data pull → fused preprocessing → inference → export), replacing a 7‑day manual workflow.

Coverage & Resolution

15,000 km² per analysis at 10 m pixel resolution, enabling dense, district‑scale operational mapping.

False Positives

Minimal (<5%), reflecting the discriminative benefit of SAR+NDWI+slope fusion under turbid water and cloud conditions.

Strategic Impact

Decision Relevance

Technical Foundation

What Makes It Work

Physics‑Informed Pseudo‑Labeling

Eliminates annotation bottlenecks and aligns supervision with hydrology, improving generalization across regions and seasons.

Hierarchical Attention

SegFormer's hierarchical attention captures flood textures (smooth water bodies, shorelines) and contextual cues (valley floors), which classical CNNs or index‑thresholding miss.

Multi‑Modal Fusion

Mitigates single‑sensor failure modes (e.g., optical cloud cover, SAR roughness over vegetation) by enforcing consensus across SAR, optics, and topography.

Deployment

Operationalization & Outputs

Deliverables

  • GeoTIFF rasters (probability and class)
  • Vector flood polygons
  • Styled overlays
  • Metrics JSON for dashboards and incident reports

Integration

Google Earth Engine pull → PyTorch inference service → GIS export; API‑ready for emergency ops centers.

Constraints

Limitations & Risks

Latency and Revisit

5–6 day satellite cadence limits truly continuous coverage, though SAR dual‑satellite constellations mitigate gaps.

Domain Shift

Extreme specular returns, dense canopy, or urban canyons can bias SAR water signatures; slope/NDWI constraints reduce but do not eliminate risk.

Compute & Storage

Training requires GPU; region archives can exceed 1 TB/year, necessitating lifecycle policies.

Roadmap

Future Scope

Real‑Time Alerting

Hourly S1 ingestion with 30‑minute inference windows for streaming situational awareness.

Damage Modeling

Fuse with building footprints and land‑use to estimate exposed value and prioritize response corridors.

Multi‑Region Scaling

Bangladesh–India–Pakistan concurrent processing with parameterized AOIs and auto‑retrains on new flood seasons.