Imagined What it could do
Imagine a courtyard where every drop of rain from the roofs runs into a sunken garden, sinks into the soil and slowly fills a clear pool, so the garden is green even in the dry season.
Real world The problem with hard cities
In nature, most rain soaks into the ground. In cities, roofs, roads and parking lots are hard surfaces, so rain rushes into drains, picking up oil and litter. In heavy storms, drains overflow, causing floods and sometimes sending sewage into rivers.
Real world How a rain garden works
A rain garden is a shallow dip planted with tough, deep-rooted plants. Rainwater from roofs and paths is directed into it. The water pools for a short time, then soaks into the soil, which filters out pollution. The US Environmental Protection Agency promotes rain gardens as part of "green infrastructure".
Some cities, especially in China, are scaling this up as "sponge cities", combining rain gardens, wetlands, permeable paving and green roofs to soak up storms.
Art In this artwork
This illustration shows a courtyard of flowers and paths around a glowing pool, with stone arches.
Look closer
- Find the pool in the middle of the garden.
- Which way would rain flow into it?
Think about it
- How could gardens collect and clean rainwater?
- Where does the rain go when it falls on your school?
- What would a "sponge city" look like?
Key words
- Rain garden
- A planted dip that soaks up rainwater.
- Permeable
- Letting water pass through.
- Green infrastructure
- Using plants and soil to manage water.
Use it in class
- Design a city: a project-based unit for grades 5 to 9 (Project, grades 5-9)
- Sustainable city project ideas for students (Project, grades 5-12)
Sources
The real-world facts on this page are based on these sources:
- US Environmental Protection Agency, "Green Infrastructure": rain gardens and green roofs
- US Geological Survey, Water Science School, "Impervious Surfaces and Flooding"
