The future of rainwater management – Irish Building Magazine

The following article first appeared in Irish Building Magazine and can be downloaded HERE

WATER WORKS

The drainage solution of the future, a sustainable urban drainage system (SuDS) is an alternative to the traditional pipes, gullies and culverts approach to a development and drainage strategy. “If you could imagine a green field,” says Michael Vaughan of Roadstone, “you’d have about a 10% water runoff. A built-up, hard landscape area could have up to 50% runoff. The sheer amount of runoff water you have to deal with is immense when you are constructing high-density developments.” Managing the water on site, minimising its runoff, infiltrating the water for passive treatment and controlling its discharge rate are the key elements of this kind of drainage. The Roadstone Aquaflow paving system provides a practical solution to SuDS.

Michael Vaughan says that the fact of the matter is that while there are drainage systems in place throughout the country, we can’t keep feeding into them forever more. “I think this is an issue the entire country will be dealing with going forward. The way we address this issue is by dealing with the water close to its source,” he explains. By doing that, we can use SuDS paving which allows the water to filter through the paving into a sub-structure, which is designed, and you have controlled release of the water back into the ground.” The Roadstone Aquaflow SuDS allows rainwater to infiltrate through a permeable block paved surface into a unique sub-base before being released in a controlled manner into the ground or storage tanks for reuse or delayed discharge. The system is capable of handling rainfall up to 4,500mm per sq.m per hour.

The water leaving the Aquaflow system is cleaned by filtration and microbial action and can be used for secondary non-potable uses such as flushing toilets and watering soft landscapes. A further advantage of Roadstone’s Aquaflow system is that roof water can be drained directly into the sub-base through a dispersion chamber. A good example of the efficient use of SuDS is the 21,000 sq.m car park with a SuDS system used by Kildare County Council offices “It takes the carpark surface water and filtrates it, then transfers it into storage tanks to be used as non-potable water in the building itself,” says Michael.

Now is the time to take notice of water management systems, according to the experts at Roadstone. “We have to look to the future, we have to put rain water management on a sustainable footing.” says Michael Vaughan. “We can’t keep putting water through existing systems because the capacity will keep increasing and increasing. We have to manage the possibility of flooding also, which happens throughout the country each year and this is one element that would help in managing it.”

The Roadstone Aquaflow paving system is ideal for new builds, and SuDS is something we will likely see as a requirement in new developments of the future, says Michael Vaughan.

“Roadstone are a one-stop shop for SuDS. Roadstone can provide a full design service for your Aquaflow paving system issuing a site specific Aquaflow design including construction depths, invert levels, restraints, drainage and any other design elements.”

Roadstone have shown full commitment to SuDS paving solutions by providing a SuDS equivalent for all their popular standard paving ranges. For example Roadstone Castlestone paving range has an Aquaflow Castlestone permeable paving equivalent. Permeable paving is available in a full range of colours including Roadstones popular blended colours. Other permeable finishes are available such as permeable porous asphalt in the form of the “Duraflow” product, permeable “no fines concrete” and “core gravel sheets” complete the permeable range.

CASE STUDY – ÁRAS CHILL DARA, SUSTAINABLE ENERGY IRELAND BUILDING OF THE YEAR 2006

  • Roadstone designed, Formpave Aquaflow system
  • 21,000m² car park
  • ML Aquaflow Paving Blocks and inbitex membrane in a 350mm deep sub-base (specification graded stone with 30% voids to maximize storage) over SC membrane to form a tanked system
  • Use of mains water reduced by incorporating filtered rainwater from the car park, which is stored to overhead storage tanks for non-potable water use.

12 YEARS ON

  • New adjacent 5,000m² asphalt carpark partially drains into the permeable paving and is accommodated by the existing system
  • Áras Chill Dara reported no standing water on the car-park even after major rain events, ensuring cleaner surfaces
  • Aquaflow ML Paving in good condition both visually and structurally
  • Today, the system is fully operational and providing water to overhead storage tanks for non-potable building services use as required