Green roofs for flood prevention
Water buffering with green roofs!
We believe in building greener cities while addressing environmental challenges like flooding. Green roofs are a sustainable way to buffer rainwater and manage stormwater runoff effectively. Our green roof solutions consist of multiple layers including vegetation, substrate and drainage systems, which work together to manage rainfall.
How do green roofs buffer water?
Green roofs consist of multiple layers that work together to manage water efficiently. Each layer has a specific function, contributing to water retention, filtration and gradual release. Here’s how they operate:
Vegetation layer
The plants on green roofs capture rainwater on their leaves and stems. Through a process called evapotranspiration, water is returned to the atmosphere, reducing the amount of water that reaches drainage systems.
Substrate layer
The growing medium or substrate stores rainwater like a sponge. It holds water temporarily, allowing plants to absorb it while slowly releasing the excess into the drainage system. This reduces peak runoff during heavy storms.
Drainage layer
This layer ensures that excess water flows away from the roof, preventing waterlogging. It is designed to maintain the structural integrity of the roof while minimizing the risk of overflow during extreme weather events.
Types of green roofs for water management
Depending on the intended use and building specifications, different types of green roofs offer unique water management capabilities.
Regular green roofs
Suitable for standard water retention needs, they buffer water within the plants, substrate, and drainage layers, releasing it slowly to the sewage system.
- Best for: Residential and commercial buildings.
- Water Management: Retains and slowly releases rainwater, reducing the burden on municipal drainage systems.
Detention roofs
Ideal for sloped roofs up to 2 degrees, these lightweight systems temporarily hold larger quantities of rainwater, gradually draining it to reduce peak runoff.
- Best for: sloped roofs up to 2 degrees.
- Water Management: temporarily holds large amounts of water, delaying its release to prevent flooding. This type is lightweight and ideal for retrofitting projects.
Retention roofs
Designed for flat roofs, they store significant amounts of water in the lowest layer, which can be drained as needed, making them effective in areas prone to heavy rainfall.
- Best for: flat roofs in areas prone to heavy rain.
- Water Management: stores significant amounts of water at the roof’s lowest layer, offering high water retention capacity. This water can be released gradually or reused for irrigation.
Green roofs against flooding
Top 3 benefits of green roofs in flood prevention
Reduced sewer overload
By holding and delaying rainwater release, green roofs decrease the risk of overloading urban sewage systems during storms.
Improved water quality
As rainwater passes through the substrate, it is filtered, reducing pollutants before entering local waterways.
Urban cooling
Green roofs absorb heat and reduce the “urban heat island” effect, which in turn lowers the intensity of weather-related events such as storms.
