Flood Resilience Across Pluvial–Fluvial–Coastal Hazards
Flooding arises from intense rainfall, river overflows, tidal forcing, storm surge, and coastal storms. In the GGBI Framework, flood resilience highlights how Green, Grey, Blue, and Intelligent elements combine to reduce risks, protect communities, and support long-term adaptation across multiple hazard types.
The Multi-Hazard Nature of Flooding
Flooding rarely occurs from a single source. Many damaging events arise from overlapping or sequential drivers—for example:
- Intense rainfall overwhelming drainage (pluvial flooding).
- Rivers exceeding channel or levee capacity (fluvial flooding).
- Tidal forcing, storm surge, and wind waves (coastal flooding).
- Combined events, such as rainfall + surge or tide + river flooding.
The GGBI Framework helps organize how interventions across the four domains contribute to managing these combined risks.
Representative Drivers and Processes
Extreme Rainfall (Pluvial)
Short-duration, high-intensity storms that generate rapid runoff and overwhelm GI and drainage systems, particularly in dense urban areas.
Riverine Flooding (Fluvial)
High river flows caused by rainfall, upstream contributions, snowmelt, or channel restrictions, affecting floodplains and downstream communities.
Storm Surge & Coastal Inundation
Hurricane or nor’easter events that raise coastal water levels, propagate inland, and interact with tides and river inflows.
Waves & Erosion
Nearshore wave processes that worsen flooding, damage structures, and reshape coastlines during storms.
Green, Grey, Blue, and Intelligent Elements for Flood Resilience
Flood resilience requires coordinated contributions from each GGBI domain:
- Green measures: infiltration, storage, wetlands, floodplain reconnection, and distributed GI that slow, retain, or absorb water.
- Grey measures: levees, floodwalls, surge barriers, tunnels, pumps, detention systems, hard coastal structures, and engineered conveyance.
- Blue environments: rivers, estuaries, bays, and coastal zones that shape how water levels rise, how flows combine, and how wetlands provide natural attenuation.
- Intelligent capabilities: monitoring, forecasting, hydrologic and hydrodynamic modeling, remote sensing, early warning systems, scenario analysis, and decision support.
The GGBI Framework helps evaluate how these measures reinforce one another—and how combinations can reduce risk more effectively than individual interventions.
Multi-Hazard Strategies
Applying the GGBI Framework supports development of integrated strategies such as:
- Combining GI with drainage improvements to reduce pluvial flooding.
- Using floodplain restoration to reduce fluvial peaks and improve ecosystems.
- Integrating wetlands or living shorelines with coastal structures.
- Coordinating river, estuary, and coastal modeling for combined events.
- Planning for compound flooding (rainfall + river + surge interactions).
- Exploring long-term adaptation pathways under climate change and sea-level rise.
These strategies benefit from linking hydrology, hydraulics, estuarine processes, morphodynamics, and local knowledge.
Connections to GGBI Framework Domains
- Green domain – GI, floodplain reconnection, wetlands
- Grey domain – engineered flood-control and coastal structures
- Blue domain – hydrodynamics, tides, surge, waves
- Intelligent domain – forecasting, data, models