Page 133 - Oxfordshire SuDS DESIGN & EVALUATION
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Permeable surfaces
Permeable surfaces enable SuDS designers edge
to direct rainfall straight into a SuDS ■ adjacent planting should include dense
structure for cleaning and storage or ground cover to bind the soil in place
infiltration into the ground. ■ slopes running toward permeable Detailed Design
There are a number of permeable surfaces surfaces should have a depression and
available. All should have in common: ideally an underdrain before reaching
the pervious surface.
1. a pervious surface to allow water through
the pavement surface The design and construction of pervious
pavements are covered by guidance in the
2. an open-graded sub-base layer that
SuDS Manual (Section 20) and the Interpave
provides structural strength to the
website www.paving.org.uk
pavement with about 30% by volume
available for water storage. There are no reported issues with surface
3. Silt washed off adjacent landscape areas clogging under normal use. A dedicated
can lead to localised surface clogging. maintenance may be required after between
This risk can be managed through design 10 and 20 years of use comprising a brush
detailing as follows: and suction removal of grit joints and joint
■ slope adjacent landscape areas away replacement.
■ use paved or turfed surfaces to
adjacent areas
■ soil in adjacent planting beds should Soft landscape areas are set below kerb level at 128
be min. 50mm below the pavement this permeable paving installation.
Almac Car Park, Limerick, Ireland.
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Oxfordshire County Council SuDS D & E Guide © 2018 McCloy Consulting & Robert Bray Associates
