Flood risk measures the probability of inundation of an area based on the historical record of flood events from 1985 to the present. The risk level (scale 1–5) is calculated by counting flood events recorded in HydroBASINS (Level 12) watersheds, weighted by severity (1–3 based on estimated damage): the greater the number and severity of historical events, the higher the risk assigned to the site.
Floods are among the most devastating natural hazards globally, with impacts increasingly attributable to climate change: increasing frequency and intensity of extreme precipitation events, changes in hydrological regimes, and expansion of impermeable surfaces (Brakenridge, 2024). The KPI integrates historical data with future projections based on a Machine Learning model trained on meteorological and climate data under SSP (Shared Socioeconomic Pathways) scenarios from CMIP6.
Phase 1 — Historical risk:
Phase 2 — Future projections (ML model):
A Machine Learning model (trained on historical flood data + meteorological variables) calculates the probability of a flood event in the coming years under different SSP climate scenarios:
Future climate data are sourced from the CDS CMIP6 dataset (WRD_CDSXX_99).
| Code | Name | Provider | Notes |
|---|---|---|---|
WRD_FLOOD_99 | Global Flood Archive (DFO) | Dartmouth Flood Observatory | From 1985 to present |
WRD_HYDRO_99 | HydroBASINS Level 12 | HydroSHEDS / WWF | Global watershed boundaries |
WRD_CDSXX_99 | CDS CMIP6 | Copernicus Climate Change Service | Future SSP projections |
| Indicator | Unit | Range | Inverted |
|---|---|---|---|
flood_risk | — | [0, 1, 5, 8, 15, 20] | Yes |
flood_risk_level | — | [0, 1.01, 2.01, 3.01, 4.01, 5] | Yes |
flood_events | — | [0, 2, 5, 10, 20, 50] | Yes |
Inverted = Yes: a lower value indicates lower risk and safer conditions for the site.
| Level | Risk index | Risk level | Interpretation |
|---|---|---|---|
| E (Critical) | 15 – 20 | 5 | Extreme flood risk; frequent and severe events |
| D (Poor) | 8 – 15 | 4 | High risk; multiple significant events recorded |
| C (Moderate) | 5 – 8 | 3 | Moderate risk; occasional events in the watershed |
| B (Good) | 1 – 5 | 2 | Low risk; rare historical events or low severity |
| A (Excellent) | 0 – 1 | 1 | Minimal risk; no relevant events recorded |
The KPI provides the following information:
flood_risk
flood_risk_level
flood_events
Flood probability based on historical events from 1985. Sources: Global Flood Archive DFO (Brakenridge, 2024), HydroBASINS Level 12 (Lehner & Grill, 2013), CDS-CMIP6 (WRD_CDSXX_99). Identifies the HydroBASINS Level 12 watershed for the polygon, extracts DFO events, weights by severity (1–3), computes risk index [0–20], classifies into level 1–5. Future projections from ML model trained on historical flood data and CMIP6 meteorological variables, for SSP1-2.6, SSP2-4.5, SSP5-8.5 scenarios. Current version: v2 (evolved from v0→v1→v2).