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Stormwater Attenuation and Filtration

The need for Sustainable Drainage (SUDS)

When any previously undeveloped site is built on and paved over, water run-off from the newly impermeable surface increases by up to 80%. This can place excessive pressure on existing watercourses and local drainage infrastructure.

So when storms bring sudden, unusually heavy rainfall, there can be localised flooding and damage to property.

Government and the Environment Agencies are now promoting the use of Sustainable Drainage Systems (SUDS) to restrict run-off to a level equivalent to that of a natural green field site.

Storage (Attenuation) or Infiltration

SUDS policy aims to achieve this in two ways:

• Temporary storage and control of excess flows, so that immediate outflow into Streams and rivers is limited.

• Efficient soakaways to infiltrate stormwater into the ground.

Rising rainfall levels, and increased focus on SUDS compliance, have led to a sharp increase in the use of Stormwater Infiltration Cell systems to create underground structures for infiltration or temporary storage of stormwater.

Benefits of these systems are:-

• Significantly reduced flooding risk.

• Controlled, reduced-volume release of stormwater into existing drainage systems or watercourses.

• Recharging of local groundwater (in an infiltration or soakaway application).

• Sustainable, cost effective management of the water environment.

Our solution; D-Raintank Stormwater Attenuation or Infiltration Crates

There are essentially two approaches to Stormwater run-off;- attenuation or storage:

1) Attenuation – Storage; Use the modular, variable layout, D-Raintank crates wrapped in an impermeable Geomembrane and Geotextile protection fleece, to construct attenuation tank, to hold the run-off and to discharge via a flow control chamber directly to the existing drainage system or water course. (Subject to necessary approvals)

2) Infiltration ; This requires the retention unit to act like a soakaway and to allow the run-off to be discharged directly into the surrounding ground.

D-RAINTANK crates wrapped in a suitable permeable geotextile such as D-Raintank Geotextile offer just such an option. If you want to contain the rainwater on site, then (subject to ground conditions) this could be the option for you