The Global Centre for Risk and Innovation (GCRI)
Parks, street trees, green roofs, wetlands, rivers and ponds are green and blue infrastructure: they cool streets, absorb and slow stormwater, clean air and water, support biodiversity and improve wellbeing. Their benefits depend on design, location and maintenance, and are often unequally shared. This page sets out how they work, how their performance is measured, and what evidence serves the city authorities and communities that plan and care for them.
GCRI · In development · service level R0
Green and blue infrastructure is the planned network of parks, trees, green roofs, wetlands, rivers and ponds that cools cities, absorbs stormwater, cleans air and water and supports wellbeing. Its benefits depend on design, location and maintenance, and are often unequally shared between neighbourhoods.
For green blue infrastructure, in GCRI's spatial-intelligence reading, the map opens on night lights, true-colour imagery, population density and land cover with relief in 3D, framed on India; 2 further NASA layers wait in the list.
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Infrastructure exposure, for this page
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NASA GIBS / EOSDIS · ASTER GDEM (METI, NASA) · Blue Marble (NASA) · © OpenStreetMap contributors (ODbL) · Natural Earth
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For green blue infrastructure, in GCRI's spatial-intelligence reading, the map opens on night lights, true-colour imagery, population density and land cover with relief in 3D, framed on India; 2 further NASA layers wait in the list.Satellite and model products as NASA publishes them, each with its own date; indicators, not assessments of any place; claim ceiling INTEGRATED.
Layers and dates
The working screen behind this subject: its structure, terms and states. Names are placeholders and values illustrative.
Nature-based urban interventions. The dossier below sets out how the risk develops, what is measured, where the data come from, how it is modelled and who decides.
Trees shade surfaces and people, and vegetation and water cool air through evaporation. The cooling is strongest in and next to green and blue spaces and fades with distance.
Permeable ground, rain gardens, swales and wetlands store and infiltrate rainwater, reducing runoff peaks. Their capacity is limited in very large storms and when soils are saturated.
Wealthier neighbourhoods often have more trees and parks. New green investment can raise property values and displace residents unless housing is protected.
Trees take years to grow and die without watering and maintenance. Green infrastructure performs only as long as it is managed, which needs budgets and skills.
Each term as this page uses it. Where a standard-setting body defines the term, the wording follows that body.
| Term | Definition |
|---|---|
| Blue infrastructure | Water elements such as rivers, ponds and wetlands managed for urban services. |
| Sustainable drainage systems | Drainage features that manage rainfall close to where it falls by storing, infiltrating and slowing it. |
| Nature-based solution | An action that protects, manages or restores ecosystems to address a societal challenge while benefiting people and nature. |
Each indicator carries its unit, its cadence, the kind of source behind it and the evidence label a value would carry. No values are shown: a programme supplies them under its own authority.
| Indicator | Unit | Cadence | Source type | Label |
|---|---|---|---|---|
| Share of built-up area that is open space for public use | percent | per assessment | SDG indicator 11.7.1 methods | ESTIMATED |
| Tree canopy cover | percent of area | per assessment | Aerial and satellite imagery | OBSERVED |
| Population within walking distance of green space | percent of population | per assessment | Accessibility analysis | MODELLED |
| Impervious surface cover | percent of area | per assessment | Satellite land cover | OBSERVED |
| Stormwater retained by green infrastructure | cubic metres per design storm | per project | Hydrological modelling and monitoring | MODELLED |
| Street trees planted and surviving | count and survival percent | annual | Municipal tree inventories | REPORTED |
The topic as a computational graph: named sources feed the methods, an evidence review gates the outputs, and the decisions stay with the authorities that hold them.
Fig. 02Nodes carry their type, two metric rows and a state; connectors show what feeds what; dashed frames name the owners; the timeline is the cadence. Design of the pipeline, not a record of a run.
Named public datasets and institutional records, each with its licence class. Sources by agreement are used only under their terms and never republished.
| Source | What it gives | Licence class |
|---|---|---|
| ESA WorldCover and Copernicus land monitoring products | Land cover and imperviousness | Open, CC BY 4.0 and Copernicus terms |
| Municipal tree inventories | Location, species and condition of street trees | Open data where published, licence per city |
| UN-Habitat SDG 11.7.1 data | Public open space in cities | Public, UN-Habitat terms (to check) |
| IUCN Global Standard for Nature-based Solutions | Criteria for designing and assessing nature-based solutions | Public, IUCN terms |
| Urban hydrology monitoring studies | Measured performance of rain gardens, swales and green roofs | Licence per publication |
Cities and Built Environment prepares evidence. The decisions below are taken by the authorities named, under their own rules, and never by the platform.
| Who decides | The question | Evidence this page serves |
|---|---|---|
| City parks and environment departments | Where to plant trees and create green space first | Equity maps; heat and canopy evidence |
| Stormwater and drainage authorities | Where green infrastructure can reduce flooding and by how much | Performance assessments |
| Housing and planning authorities | How to green neighbourhoods without displacing residents | Equity and housing evidence |
Cooling, flood storage, water quality, biodiversity and health benefits, and how they vary with design and scale.
How performance changes with drought, maintenance and extreme events beyond design.
Whether green space is distributed fairly or raises land values and displaces residents.
Where hybrid designs outperform either approach alone.
Vegetation cools through shade and evaporation. Permeable surfaces and wetlands slow and store runoff, reducing flood peaks. Soils and plants filter pollutants. These effects are real but depend on species, water availability, maintenance and the size and connection of green areas.
Nature-based measures have different risk profiles from engineered ones. They may take years to mature, can fail in drought or disease, and their capacity in extreme events is harder to specify. They also deliver co-benefits engineered systems do not.
Greening can raise property values and rents, a process sometimes called green gentrification, which can displace the residents it was meant to help.
Climate change alters the baseline. Species chosen today must cope with tomorrow's heat and drought, and urban trees under water stress cool less. Design therefore needs to plan for irrigation, species diversity and replacement over decades.
| Method or data | What it shows | Its limit |
|---|---|---|
| Field monitoring | Measured cooling or runoff reduction | Site-specific; hard to generalize |
| Hydrological models | Flood storage under design storms | Uncertain for extremes beyond calibration |
| Remote sensing of vegetation | Canopy cover and change | Does not show condition or function |
| Social surveys | Use, perceived benefit and equity | Self-report limits |
The current service level is R0: information and enquiries. An enquiry receives a reference and names the next step; applications, payments, compute allocations and registrations open only when their team, terms and review capacity exist.