SuDS in London - a guide

• Instill a sense of pride within
the local community
• Provide a multi-functional space that
could be used for a variety of events
• Provide educational potential,
while being safe for the children
who use the site on a daily basis
Actions and results
• Permeable block paving (1,320m²)
allowed retention of existing site
levels, negating the need to excavate
the existing concrete road slab.
The 180mm permeable pavement
depth can cater for heavy loads
• The permeable paving and the
disconnected downpipes from the
surrounding school and playground
buildings direct rainwater to heavily
planted bioretention basins and
rain gardens, providing over 55m
of additional attenuation
• The scheme uses sculpture to
replace traditional downpipes to
make the scheme distinctive. The
sculpture also provides an important
security deterrent against those
trying to access the school roof
• Flow controls are designed to restrict
flows to below 1 L/s (less than the 5 L/s
generally adopted by industry) and retain
flows on site for longer. This is achieved,
in part, by designing drainage outlets
that minimise the risk of blockage,
yet ensure easy access and safety for
council staff to inspect and maintain
• Interpretation boards explain the
design; monitoring equipment
provides performance evidence
Benefits
• Carriageways adaptations have made
the use of community assets safer
• Reduction in local and wider flood risk
• The attenuation of water and its
associated vegetation have contributed
to air quality (principally NOx and
PM) and water quality (hydrocarbons
and total suspended solids)
• The ecological considerations
(hydrological and vegetative) have
provided a site for biodiversity that
will increase as the scheme matures,
while providing an educational
resource and community buy-in
to monitoring and maintenance
After
• Annual flow volumes into the
combined sewer overflow
have been reduced by 50%
Lessons learned
• Supervision of SuDS construction
by designers was essential
to successful delivery
• Involvement of the construction
contractors early in the design
process ensures the best outcome
98 5 Case studies