drainage

Inglefield Drainage Plans - click for larger image
Inglefield Drainage Plans - click for larger image

The site lies in Flood Zone 1, a significant distance from the 1 in 1000 year floodplain.

The development will:

NOT build in the 1 in 100 or the 1 in 1,000 year floodplain;
NOT increase drainage run-off;
NOT increase the risk of flooding elsewhere;
NOT adversely affect the Chichester and Langstone Harbours Special Protection Area (SPA), Special Area for Conservation (SAC), RAMSAR site and Special Site for Scientific Interest (SSSI) to the south of the site;

ESTABLISH a Sustainable Drainage System to collect surface water run-off from the site, restricting surface water run-off to the pre-development conditions, and improve water quality to drinking water standards wherever possible;
CONNECT to the Southern Water foul water sewerage system via a network of adopted sewers across the site; and
CREATE water control features to improve amenity, landscape character and site ecology.

With reference to the adjacent images:

Images 1 and 2: Illustrate a typical surface water attenuation basin in both plan and section.
Images 3 and 4: Illustrate typical examples of surface water attenuation basins with both reed planting (Image 3) and open water (Image 4) providing habitat for wetland flora and fauna.

Our current drainage strategy is as follows:

  • The construction of a new Surface water attenuation basin to the south west of the site. The attenuation basin will be designed to include some permanent water as well as marshy habitat in order to diversify habitats across the site and for the visual amenity of residents.
  • A new swale is proposed to capture and convey surface water to the attenuation basin. The swale may comprise of a shallow channel or grassed depression into which surface water is directed during heavy rainfall events.
  • The Existing field ditch will be retained, cleared of debris and connected into either the swale and / or attenuation basin.
  • The development has been designed so that roads link east to west through the site. Surface water will collect along these road routes and will be directed west to flow towards the swale and ditch.