Suds for the Salvation Army - 'Green' Drainage Solution for New Training Centre
24 May 2005, News release from Netlon Turf Systems
When architect Bernard Gooding of Leigh on Sea was given the task of designing the car park for a new Salvation Army training centre in Hadleigh, Essex, he decided that, instead of traditional drainage, they would recommend a green alternative - a Sustainable Urban Drainage System.
The 1,700 square metre car park site stands in the middle of 700 acres owned by the Salvation Army and is bordered by a brook into which car park outfall would flow and where potential contamination by pollutants from parked cars was a concern.
"The area is environmentally sensitive and our view was that in this case SUDS was the ideal solution. The Salvation Army accepted our recommendation."
Having made the choice the architect contacted Netlon who, in conjunction with specialist SUDS consultants EPG (Environment Protection Group), provided the total solution.
The system proposed - and implemented - incorporated Netpave 50, the permeable cellular plastic paving from Netlon. The cellular structure of the unique flexible pavers means that they can accommodate either a grass or gravel finish. At Hadleigh Netlon's advice was that the frequently trafficked access routes should be gravel filled while the parking bays should be grassed.
"The other big advantages of Netpave 50 is that it is produced from 100% recycled materials which means that the system is green from start to finish," said Mr Gooding.
The Netpave 50 acts as the "source control" for the drainage system, allowing rainwater to infiltrate through to the sub-base and then pass through various forms of attenuation and filtration rather than being taken directly into pipes or culverts.
Beneath the Netpave 50 and its bedding layer of either rootzone or gravel is a geotextile membrane which provides an initial filter layer for pollutants and fine particles and is supplied by Netlon's parent company, Tensar International. Immediately below the membrane is a combination of free-draining sub-base and a Permavoid storm water management system - a high strength interlocking plastic box structure with integral diffusion facility which attenuates and controls the flow of the rainwater.
The final element in the system comprises a layer of Tensar SS30G - a geogrid with a geotextile bonded to its underside. The geogrid provides structural integrity to the whole system and also enables a reduction in the total sub-base thickness required whilst the geotextile provides a further barrier against contaminants.
Now fully established the system, which is designed for a 1 in 30 year storm event, is working well and is providing the right aesthetics for the area. "It is the first time we have used Netpave 50 and we are very pleased with the result," said Bernard Gooding. "The grass has greened up very well and we now prefer Netpave to cellular concrete paving which we have used in the past."
"SUDS is the way forward for drainage and we can't see why more people aren't using it," he added. " From a cost viewpoint there is little difference between the environmentally sound SUDS systems and traditional drainage.
"In addition, SUDS prevents wastage of water. If a traditional drainage system had been installed at Hadleigh the rainwater would have ended up as salt water in the sea.
"In the future, where appropriate, we will recommend SUDS and will use Netpave. We are currently working on plans for a school car park and are actively encouraging the client to adopt a SUDS solution."
Phil Allen, who co-ordinated the Netlon and Tensar elements of the Hadleigh project said that, whilst in this instance the adoption of SUDS had been architect-led, Sustainable Urban Drainage Systems are of growing importance in flood prevention and environmental terms.
"The Hadleigh project demonstrates just how effective both Netpave 50 and Tensar geogrids can be in providing both practical and aesthetically pleasing solutions to the vexed question of urban drainage."
The Hadleigh system was installed by contractor Jardim Vista.
For further information please email Netlon Turf Systems