Blue Environments in the GGBI Framework

In the Green–Grey–Blue–Intelligent (GGBI) Framework, the Blue domain encompasses rivers, estuaries, bays, coasts, and other water bodies where flows, tides, waves, sediment, and ecosystems interact. Blue environments connect upland watersheds with coastal and marine settings and are central to flood behavior, navigation, ecosystems, and human use.

Rivers & channels Estuaries & bays Coasts & shorelines Tides & storm surge Waves & sediment Wetlands & marshes

Role of Blue Environments

Blue environments provide the pathways and spaces through which water, sediment, and constituents move from inland areas to the ocean. They also host ecosystems and human activities that are sensitive to changes in flow, water level, and water quality. Key roles include:

Conveying river flows, storm surges, and tidal motion.
Storing and redistributing water in channels, bays, and coastal embayments.
Supporting estuarine and coastal ecosystems, including wetlands and marshes.
Shaping sediment dynamics, erosion, and deposition along channels and coasts.
Providing spaces for navigation, fisheries, recreation, and waterfront development.

In the GGBI Framework, understanding Blue environments is essential for connecting upstream interventions to downstream impacts in estuaries and along the coast.

Representative Processes and Settings

Rivers and Tidal Channels

River reaches and tidal channels convey flows from upland watersheds to estuaries and bays. Their behavior reflects interactions among discharge, tides, geometry, and sediment.

Estuaries and Bays

Transitional zones where river inflows mix with coastal waters. Estuaries exhibit tidal circulation, stratification, salinity gradients, and complex exchanges with adjacent wetlands and channels.

Coastal Shorelines

Open coasts, beaches, and nearshore zones affected by waves, currents, water-level variations, and sediment transport. Shoreline change is influenced by both natural processes and human interventions.

Wetlands and Marshes

Vegetated intertidal and shallow-water areas that provide habitat, wave attenuation, nutrient processing, and floodwater storage, and are often highly sensitive to water-level changes and sediment supply.

Blue environments are often where multiple drivers—river flows, tides, storm surge, waves, and sea-level rise—combine. Their response to events reflects contributions from both inland and coastal processes.

Interactions with Green, Grey, and Intelligent Domains

Blue environments interact with other domains in ways that strongly influence resilience and environmental outcomes:

With Green: Watershed-scale Green practices affect hydrographs, sediment loads, and water quality that ultimately reach rivers, estuaries, and coasts.
With Grey: Levees, navigation channels, tidal gates, surge barriers, and coastal structures modify water levels, currents, and sediment pathways in Blue environments.
With the Intelligent layer: Monitoring networks, hydrodynamic and morphodynamic models, and decision-support tools help interpret complex behaviors and evaluate adaptation options under climate variability and sea-level rise.

The GGBI Framework emphasizes these cross-domain linkages to support planning that spans from watersheds through estuaries to the open coast.

Links to Applications on This Site

The Blue domain connects most directly to:

Future case studies may illustrate how Blue environments respond to combined influences from Green, Grey, and Intelligent interventions.