A new concept in water attenuation and pollution control on commercial buildings.
The principal parties involved in the development of this project have been involved in the geotechnical and roof greening industry for many years and have a combined experience of over 35 years. During this time they have acquired considerable knowledge of the success and shortfalls of applying green roofs and gained a broad understanding of waterproofing. This experience has led to an understanding that there is an ever growing need for water attenuation on roofs as opposed to simply capturing rainfall in large reservoirs/tanks.
There is an ever growing need for water attenuation on roofs as opposed to simply capturing rainfall in large reservoirs/tanks.
Whilst people appreciate the aesthetic qualities of a green roof, there are barriers that need to be overcome, not least of which is cost, and so Aquaten has developed a product that is easier and more economical to fit than either a green roof or a stand-alone water attenuation tanking system.
A common definition of flash flooding by broadcasters is that a number of day’s rainfall has occurred within a few hours and it is understood that attenuation of the first 5 mm of rainfall is critical.
The Aquaten Solution
Our objective was to develop a product and system that will be perceived as a functional solution to the water attenuation problem, without the perceived barriers of existing water attenuation systems. Notwithstanding the environmental issues, cost remains a key barrier so we set out to develop a product that could bring a real cost benefit, while attenuating the first 5 mm of flash flood run off.
We have developed a lightweight roofing tile or blanket containing a highly super absorptive water attenuating fibre, which absorbs and holds three days of average rainfall, releasing back into the atmosphere through trans-evaporation or into the watercourse in a controlled manner.
We have also produced an highly water absorptive geo-matrix that can be applied to a roof (flat and pitched) and will be able to withstand degradation for 5 years minimum from wind, rain and ultra-violet light.
The product can be self-bonded to a wide range of roof surfaces (surfaces commonly used such as asphalt, slate, concrete and terracotta tiles, PVC, HDPE etc.
The product will attain high levels of water absorption, as well as optimum evapotranspiration properties to allow the material to ‘re-charge’ over a 5-day period in order to maximise its attenuation benefits. We aim to retain the first three days of average rainfall volume, approximately, so it can be seen that it is a major advance in fighting the problem of urban flooding.
The product is modular thus alleviates the problems associated with fitting, i.e. weight, labour intensive, specialist skills and heavy machinery particularly when working in dense urban areas. The concept we have developed is much more than just a green roof and has water attenuation as its key and critical purpose. The product will work as a standalone system and/or in conjunction with a green roof build.
There are currently existing water absorbent materials that are used in a range of products from healthcare to fire safety, however they do not meet the needs of a water attenuating product to be used on roofs.