10 Superior Green Roof Stormwater Control Designs Soon to Be Tested

The Purple-Roof® “enhanced by Urbanscape®” concept, a joint effort between Sedum grower Sempergreen from Virginia, in the USA, and binder-free mineral wool growing media supplier Knauf Insulation from Slovenia, EU (part of the German Knauf Group) is taking on a whole new dimension.

Optimal Combination of Stormwater Management and Green Aesthetics

“Over the course of testing in past years we have discovered so many new things. We now understand how to modify the green roof design to optimize rainwater control on the roof and to supply civil engineers with improved information to conduct their work. We know precisely how to apply different growing media strategies to achieve the best outcomes. Initially, we focus on maximizing stormwater control, and once this is functioning satisfactorily, we also evaluate how the plants grow according to the new designs. We have had more than 30 green roof designs established on the premises since 2012, and we can identify what works best in terms of appearance. Our aim is to provide the optimal combination of stormwater management and green aesthetics,” says Oscar Warmerdam, President of Sempergreen USA.

Provide a Concept That All Major Green Roofers Can Use

“We have been conducting intensive stormwater testing back in Europe for the past four years to better understand our unique Urbanscape® mineral wool growing media as part of the Urbanscape® Green Roof System. In North America, we are taking it a step further. We aim to design a concept that is easy to implement across the wider green roof industry. We do not wish to sell our own system on the market, but instead aim to provide a concept that all of the major green roofers can utilize as their own – or as an addition to an already existing portfolio,” says Jure Šumi, director of global business development for Urbanscape® Green Solutions.

Provide a concept that all major green roofers can use

“We have been conducting intensive storm water testing back in Europe for the past four years in order to better understand our unique Urbanscape® mineral wool growing media as part of the Urbanscape® Green Roof System. In North America, we are taking it a step further. We aim to design a concept that is easy to implement across the broader green roof industry. Our goal is not to market our own system, but rather to offer a concept that all of the major green roofers can adopt as their own – or as an enhancement to an already existing portfolio,” says Jure Šumi, director of global business development for Urbanscape® Green Solutions.

New additions to Storm Water Lab

The storm water lab, which was designed by Sempergreen USA in 2016 with support from Knauf Insulation, American Hydrotech, Firestone, and Greenrise, has now been further upgraded in 2017. Numerous new additions have been made to simulate and replicate, with high precision, extreme storms that can last up to six hours.

Simulation of Four Rainfall Distribution Zones

There are currently four rainfall distribution zones in the USA, each with their own typical extreme rain events that can now be simulated in the storm water lab. The Purple-Roof “Enhanced by Urbanscape®” concept will be tested according to all four scenarios in order to gain accurate data on specific rainwater detention and retention characteristics during specific super storms typical for each of the four zones.

It might appear that this is a very general approach, but each region has a certain storm type, and within the storm type there are local intensity and volume values that apply – as we know that average rainfall differs from city to city, this is a common approach for civil engineers when planning storm water management measures.

The ultimate goal will be to custom design green roofs for every major city, taking into consideration:

• Maximum storm water retention and detention during a typical storm in order to prevent floods and pollution.
• Maximum annual storm water retention, in order to minimize the burden on sewage treatment facilities.