Unsupported browser

For a better experience please update your browser to its latest version.

Your browser appears to have cookies disabled. For the best experience of this website, please enable cookies in your browser

We'll assume we have your consent to use cookies, for example so you won't need to log in each time you visit our site.
Learn more

Case study

  • Comment

When developer Barratt wanted to build 350 homes at Alma Dettingen Barracks, Deepcut, Surrey, Thames Water imposed a strict maximum surface water discharge rate of 5 litres/ second to avoid overloading the current system in times of heavy rainfall. Consultant Hemsley Orrell Partnership was called in and, together with Thames Water, developed a sustainable rainwater proposal to manage the run off. One natural advantage was the gravelly sand matrix substrate which permitted natural percolation.

The project was zoned into three catchment areas; primary roads, secondary roads and roofs/drives. The primary roads were positively drained. A conventional gully and pipework system runs into a large (400m 3) storm cell manufactured by Hydro in the centre of the site, concealed under a grassed amenity area. This provides a 'buffer' against a 20-year storm, and incorporates a regulated outfall. Additional storage was designed in by allowing back up through the pipework in the event of the tank reaching capacity.

The secondary roads and drives were constructed from FormPave permeable concrete paving, which allows rainwater to percolate through and re-charge the water table. The roof water was collected via a conventional gutter system and piped into the granular bedding under the FormPave structure. An additional benefit was that the roads could be laid virtually flat. The scheme has now been adopted.

  • Comment

Have your say

You must sign in to make a comment

Please remember that the submission of any material is governed by our Terms and Conditions and by submitting material you confirm your agreement to these Terms and Conditions.

Links may be included in your comments but HTML is not permitted.