EFFECTIVE DRAINAGE WITH PERMEABLE PAVING

7 November 2014

 

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Aquaflowith the constant cry for better water management due to ageing and leaky infrastructure, the need to recycle non potable water for activities such as sanitation and landscaping becomes more critical. It makes sense more than ever before to consider technologies that will not only drain excess water effectively, but also enable water ‘harvesting’ to be conducted easily and efficiently.

 

Industrial and residential developments, in particular, those which have landscaped and paved walkways and driveways often do not have sufficient storm water drainage systems, causing enormous water wastage that could be recycled for better use if water harvesting technologies had been considered before the development commenced.

 

Sustainable Urban Drainage Systems (SUDS) offer precisely such opportunities.SUDS are used to prevent and alleviate flooding and unwanted water run-off in areas such as car parks (where these systems are implemented for storm-water attenuation reducing damage to natural waterways from rapidly flowing water), industrial estates, domestic drives and airport service areas.

 

Aquaflow Paving

Aquaflow permeable paving, from Technicrete, part of the IS Group, allows heavy rain to infiltrate through a permeable concrete block pavement via special slots in the concrete paving blocks, into a special sub-base consisting of stone, where the storm water is then retained in the stone matrix. The water is then ready for re-use or for controlled release into sewers or gray water supplies, thereby eliminating excessive pressure on existing storm water systems.

 

Heavy metals, hydrocarbons, rubber, dust, silts and other debris which are generally deposited on impermeable surfaces during dry weather, are removed to treatment works, rivers or streams during rainfalls causing severe environmental damage and severe secondary pollution. The Aquaflow permeable paving provides two solutions – superior water harvesting and environmental protection.

 

The permeable paving not only requires less space because of more efficient land use, it is also a more cost effective solution, with the permeable paving offering instant pollution control at source. Analysis of water exiting from the Aquaflow system has been found to be as clean as water from a modern sewage works and with a pH of approximately 7.5, it makes recycling sense to utilise these SUDS philosophies and paving techniques in local water harvesting operations. For example, educational establishments and backpacker hostels are using water passed through and filtered by this system for non-potable purposes such as lavatory flushing, while horticultural enterprises are using the technique to water plants and soft landscaped areas.

 

It has been established that even after 25 years, where 90% of the surface permeability has been lost through silting, the permeability of a surface is still (a column of) 9000mm x 10% or 900 mm of water per hour per m2 ( 0.9m3 or 900 litres / hour / m2 ), making the Aquaflow system still capable of dealing with exceptional and heavy rainfalls.