Green Roof Water Retention

Water storage and discharge delay.

Green roof water retention.

Although there are no precise definitions of them an extensive green roof has a shallow growing medium usually less than six inches with a modest roof load limited plant diversity minimal watering requirements and is often not accessible. Yes every green roof absorbs and buffers water. Drainage and water retention elements with low medium or high retention capacity are components of the green roof system. Note that there was very little if any runoff during the may 1 to sept 30 growing season.

Green roofs typically provide stormwater retention as they capture water preventing water from draining and then allow the water to evaporate only through evapotranspiraton processes. Retention works like this. Rain falls onto a relatively dry green roof and the green roof absorbs the water usually in pore spaces later the sun comes out and the plants use the rainwater to evapotranspire. The most critical role of the drainage layer is to provide an adequate flow of water off the roof during and after rainfall.

The cuspate is overlaid by a bonded geotextile to prevent any blockages. System solutions with defined water retention. Manufacturers whose materials we use for landscape works are well known all over the world. This means that the water leaves the roof as vapor.

Our company offers consultancy and turnkey projects for green roof and terrace design landscape and long term maintenance in order to obtain the best results. Green roof solutions offers many different drainage layer options depending on system goals regarding water retention. Discharge coefficient cs according to fll. Green roofs are also known as vegetative or eco roofs.

We need to think differently about the main purpose of a green roof. Such an extensive green roof will have a water retention capacity up to 44 l m and a surface weight in water saturated condition about 130 kg m. However a purple roof retains more water than any other green roof concept. They fall into three main categories extensive intensive and semi intensive.

Figure 2 shows the daily rain and associated daily green roof runoff for 1993 in state college pa for a green roof having a maximum of 1 6 inches of water retention storage. Geofabrics manufacture water retention and drainage boards designed specifically for living roofs. High level of reduction of of water discharge during high intensity rainfall whilst retaining good drainage even for large roof areas peak discharge. The secret of green roof water retention is green.

Suitable for blue roofs. The purple roof is the only concept that has been exposed to real life assembled testing in a professional setting.