Why water reservoir panels?
An intensive vegetation usually has a high evaporation and therefore a high demand for water. Irrigation adapted to the vegetation is also usually not possible for economic or practical reasons. In addition, the water stored in the substrate is only partially available/absorbable by the plants, so that the substrate layer must be applied thicker. The disadvantages of this are a higher roof load, construction height and costs for roof construction and substrate. When water is stored in the drainage system or a separate water retention layer, the water only ends up in the medium growing / substrate layer through evaporation. A natural water supply to the vegetation through capillarity is therefore not possible.

Water reservoir panels: water storage in a natural way
When using ND WSM Water Reservoir Panels, water can be stored naturally and made available to the vegetation again. This is comparable to a natural soil profile in which the top layer contains a lot of organic material and where the groundwater is located in the mineral sub-layers. The water from the green roof can rise capillary due to the direct contact of the medium growing/substrate layer with the ND WSM Water Reservoir Panel. The same capillary rise takes place in groundwater. In this way, the substrate layer won’t stay too wet. When the ND WSM Water Reservoir Panel is saturated, the excess water seeps into the underlying ND Drainage System that drains the water from the roof.

ND WSM-50 Water reservoir plates: water management independently and regulated as required
The direct contact of the ND WSM Water Reservoir Panels with the substrate allows the plants to independently and naturally regulate their water demands. By using the ND WSM Water Reservoir Panels, there is no hydrostatic pressure on the waterproofing membrane.

To achieve the desired water retention/buffering, it is necessary to apply a special waterproofing membrane on roofs with limited fall. This is not necessary with the application of the ND WSM Water Reservoir Panels. The water reservoir panels create a slope in the roof that enables installing any type of waterproofing membrane.

Water reservoir panels as an additional filter layer
The ND WSM-50 Water Reservoir Panels can act as an extra “filter layer”. Because of this additional filter function finer substrates or sandy soil with a higher organic content can be applied/used. As a result, a more natural soil structure is built, in which more soil life (micro-organisms) is possible, and which will increase biodiversity. This also has an economic advantage because the materials of the substrates are locally available, so that the substrates can be produced and supplied in a cheaper way.

Testat
Kiwa MPH Bautest GmbH – Research of the filter stability of the ND WSM-50 Water Reservoir Panel in combination with topsoil.