Green Infrastructure in the GGBI Framework

In the Green–Grey–Blue–Intelligent (GGBI) Framework, the Green domain represents ecological and nature-based components that manage water through infiltration, storage, evapotranspiration, and landscape processes. Green infrastructure helps reduce runoff, support ecosystems, and provide co-benefits in urban and watershed environments.

Green infrastructure Rainfall–runoff Permeable surfaces Green roofs Rain gardens & bioretention Sponge city concepts

Role of Green Infrastructure

Green infrastructure is often the first line of interaction between rainfall and the built environment. It modifies how water enters and moves through a catchment, providing opportunities to:

Intercept, store, and infiltrate rainfall before it becomes runoff.
Reduce peak flows, runoff volumes, and pollutant loads reaching grey systems.
Support evapotranspiration and microclimate regulation (e.g., on green roofs).
Enhance habitat, biodiversity, and visual/amenity value.
Contribute to sponge-city, low-impact development, and nature-based strategies.

In the GGBI Framework, Green measures are considered together with Grey, Blue, and Intelligent elements to evaluate combined performance and trade-offs.

Examples of Green Infrastructure Practices

Rain Gardens & Bioretention

Depressed or planted areas that capture and infiltrate runoff, allowing water to percolate through engineered soils and be taken up by vegetation. Often used to manage roadway, parking, or roof runoff.

Permeable Pavements

Engineered surfaces that allow water to pass through joints or voids into an underlying storage layer. They reduce surface runoff, delay flow, and support groundwater recharge where conditions allow.

Green Roofs

Vegetated roof systems that store rainfall in substrate layers, promote evapotranspiration, and moderate roof temperatures. They reduce roof runoff and contribute to building and urban-scale benefits.

Vegetated Swales & Buffers

Channels, strips, and buffers that convey runoff more slowly than traditional pipes, promoting infiltration, sediment deposition, and pollutant attenuation along the flow path.

Many Green practices operate at relatively small spatial scales (e.g., a roof, street, or block), but their cumulative effects can be significant for neighborhood and watershed responses when they are planned as part of an integrated portfolio.

Interactions with Grey, Blue, and Intelligent Domains

Green infrastructure interacts with other domains in several ways:

With Grey infrastructure: Green practices can reduce inflows to pipes, sewers, tunnels, and storage facilities, potentially lowering design loads or extending the service life of grey systems.
With Blue environments: By reducing and slowing runoff, Green measures influence flows, water quality, and sediment delivery to rivers, estuaries, and coasts.
With the Intelligent layer: Monitoring, modeling, and analysis help evaluate Green performance, optimize siting and design, and support adaptive management and communication.

Considering these interactions is essential when Green infrastructure is used to support broader goals such as flood mitigation, water quality improvement, and climate adaptation.

Links to Applications on This Site

On this website, the Green domain is most directly connected to:

As additional case studies are added, this page can point to specific examples illustrating how Green infrastructure contributes to the overall GGBI Framework.