Water retention systems | extensive vegetation
The water retention and controlled drainage system for extensive green roofs. By temporarily or permanently storing rainwater on the roof, peak discharge is reduced, providing a sustainable solution for climate-adaptive stormwater management in urban environments.
The system is based on the ND WSE-80 Water Retention Element in combination with a flow control device. Together, they provide controlled discharge and a temporary water storage capacity of approximately 72 l/m².
For optimum climate-adaptive performance, Nophadrain recommends combining water retention with water buffering and, where required, capillary water transport. This allows stored rainwater to be used more effectively by the vegetation while keeping the growing medium moist for longer. Catch it. Keep it. Re-use it.
Technical data
Example composition
Extensive vegetation (blankets, plug plants or cuttings)
Root-resistant waterproofing membrane
One complete system for extensive green roofs
Our water retention systems are supplied as a complete solution, from the protection and filter layer to the ND WSE-80 Water Retention Element and the vegetation layer.
The ND WSE-80 consists of two stacked drainage boards and has been specifically developed for extensive green roofs with limited build-up height and lower load requirements.
Water buffering and system performance
In combination with a flow control device, rainwater is temporarily or permanently stored and discharged at a controlled rate into the roof water outlet. This reduces peak discharge while creating a stable water buffering system on the roof.
The stored water remains available for the vegetation, helping to maintain a consistent moisture level within the growing medium.
Optional capillary water transport
Where additional water availability for vegetation is required, the system can be enhanced with ND KS Capillary Strips and the ND KV-200 Capillary Geotextile. These components transport stored water by capillary action from the water retention elements into the growing medium, ensuring a more uniform moisture supply for healthy plant growth.
Benefits and system solutions
By combining water retention and water buffering, rainwater is temporarily stored on the roof and released in a controlled manner. This reduces peak loads on the roof outlet during heavy rainfall and lowers the risk of urban flooding. At the same time, the system contributes to evapotranspiration, urban cooling and improved stormwater management.
Combined with the ND AFC-100 Adjustable Flow Control, this system provides one integrated solution for water retention, controlled discharge and the reuse of rainwater on extensive green roofs.
