Page 26 - Hillingdon SuDS DESIGN & EVALUATION
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6.0 Local SuDS requirements for
Local SuDS requirements
Hillingdon
Landscape Character Landscape geology
Hillingdon is London’s second largest The dominant solid geology within Hillingdon
borough, by area, covering 42 sq. miles (109 is the London Clay Formation. To the north of
sq. kilometres) with a population of 273,936 the Borough, within the vicinity of Ruislip and
according to the 2011 Census. Northwood, outcrops of the Lambeth group
(formerly known as the Woolwich and
The borough has a distinctive character with Reading beds) occur within river valleys.
its combination of suburban streets and Along the western boundary of London and
shopping centre’s, industrial land, major office Hillingdon you find the beginning of some
developments and large areas of open land, areas of Chalk are located within the vicinity
historic woodland and inland waterways of the River Colne, which identify the edge of
including 4,960 hectares of Green Belt.
the London basin.
The River Colne borders the borough to the However the depth at which London Clay
west and the Yeading Brooks which are more band can be found varies considerably. In
fast flowing becoming the River Crane to the the southern area of Hillingdon there are drift
east. The River Pinn is a particularly fast deposits overlying the solid geology. These
21 responding watercourse. There are a large consist of pockets of Langley Silt (sandy clay
number of ordinary watercourse criss- and silt ’brick earth‘) overlying the River
crossing the area.
Terraced Deposits (mainly gravels). To the
Despite remaining one of London’s greenest north of the A40 drift deposits are limited to
boroughs, Hillingdon has a pivotal role in the pockets of Glacial Sand and Gravel, Along the
economic success of the capital being the line of river channels, alluvial deposits are
home of Heathrow Airport, as well as located and in some areas the underlying
managing the environmental impacts of the solid formation has been exposed.
area such as air quality and noise that Although a predominant clay geology results
appropriate planting within SuDS schemes in much lower infiltration rate, this does not
can and should help address.
prevent the use of SuDs within a
The area is served by separate surface water development, however it reinforces the need
and foul sewers however the information on for SuDs to be integrated within design at an
the condition, location and appropriate sizing early stage and the appropriate tests
of the sewerage provision is poor and may undertaken to understand the site specific
need to be investigated. infiltration rates.
London Borough of Hillingdon SuDS D & E Guide © 2018 McCloy Consulting & Robert Bray Associates
