SuDS in London - a guide

Actions and results
• Runoff is diverted at the surface into a
gully in Redston Road and collected in
a five-sett channel that directs water
onto the grass verge along Priory Road
• Verge re-profiling carries water for its
full length until it reaches the sewer
• Early observations indicate that
water flows quickly into the rain
meadow but slows as it travels
through the grass, soaking into the
tree-lined verge before reaching the
letterbox outfall to a road gully
• Surface dressing with topsoil and low
earth banks (bunds) has minimum impact
on the trees, with simple wildflower
meadow seeding for open soil areas
• The river is within the sub-catchment
area of the line and, to a lesser extent,
nearby roads. This has implications
both for pollution and bank stability
of the River Ingrebourne as well
as the reliability of the line
• High intensity summer storms will
be diverted from the sewer and
cooled before release to the river
• Monitoring will show the extent of
interception loss and the protection
offered to the River Moselle
Lessons learned
• Importance of contractor selection
• The value of expert supervision
• How sites, that might otherwise
be considered unsuitable for
SuDS, can provide benefits with
minimum intervention
• Performance will improve
as the meadow grows
• The client partnership with Thames21
and Haringey Council are considering
monitoring opportunities
Benefits
• This simple SuDS retrofit shows
how an existing urban green space
can bring significant benefits to
unprotected urban watercourses
Images courtesy of Robert Bray Associates
• Surface collection of runoff
avoids any significant excavation
or spoil for removal
Conveyance of water through the scheme
78 5 Case studies