Page 136 - Bexley SuDS DESIGN & EVALUATION

Detailed Design Channels and rills

Sett Channels and rills keep rainwater at or
near the surface. This is important as it allows
water to flow directly into SuDS features
reducing cost, trip hazards and the
inconvenience of deep structures in the
landscape.

In some places a grated surface channel may
be more appropriate but the mesh size
should not be too small or the grating will be A planted rill at Bewdley
School Science Block.
prone to blockage.
Collecting runoff from a road can be more
difficult where there is a path present and a
flush kerb inlet or chute gully may be needed.

Use of pipes
Although SuDS are delivered without the
requirement for extensive piped networks,
short lengths of pipe can still be very useful

in providing connections under roads, A granite sett channel collecting and conveying
131 footpaths and other crossing points. Key runoff at Holland Park, London.

points to consider are as follows:

■ Short lengths of pipework should allow
direct rodding from one end of the pipe
to the other without the need for internal
chambers.

■ Inlets and outlets should be designed so
that they are not prone to blockage.
■ An exceedance flow path should be
Concrete pipe surround has been used here to
integrated into the development surface provide minimal cover for a driveway crossing at
above pipework to ensure that Devonshire Hill, Haringey.
unpredictable flows are directed SuDS
immediately after the crossing.
■ The depth of the downstream component concrete surround can be considered to

should not be artificially increased due to minimise cover - as used for driveway
a requirement for structural cover over crossings at the Devonshire Hill project
pipework. Different pipe materials or above.

London Borough of Bexley SuDS D & E Guide © 2018 McCloy Consulting & Robert Bray Associates