Hillingdon SuDS Design & Evaluation Guide

Source Controls providing collection &
conveyance
Water must either be kept at or near the
surface to allow runoff to flow into SuDS
structures, or it must be collected through
permeable surfaces.
The simplest method of collection of runoff
from an impermeable surface is to intercept it
as sheet flow from a hard surface. Where
runoff flows directly from hard surfaces to
filter strips or swales then runoff must leave
the hard surface effectively without the risk
of ponding.
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swales
filter drains
Pershore High School, Worcestershire.
Low risk access road with 1.2m wide filter strip
source control and conveyance swale.
Detailed Design
Site Controls
Where runoff is collected at the surface, a
depression in the ground, mimicing hollows in
the natural landscape, is the easiest and most
cost effective way to manage large volumes
of water in the landscape.
Where landscape is limited, storage
opportunities within pavements and on roofs
should be explored.
Careful design can maximize opportunities
with different design volumes in different
places providing maximum opportunities for
multi-functional use and biodiversity.
Pershore High School, Worcestershire.
Swale conveyance into pond site control for
final treatment and storage.
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basins
wetlands
ponds
storage structures
London Borough of Hillingdon SuDS D & E Guide
© 2018 McCloy Consulting & Robert Bray Associates