Page 27 - Enfield SuDS DESIGN & EVALUATION
P. 27
The number of properties at risk of flooding There is a wide range of existing SuDS
is high compared to most other local techniques in operation across Enfield. Some
boroughs. Most of the properties at risk of of these are relatively old features such as
fluvial flooding are in the Lee valley area, highway drainage ditches and ponds, more
which was historically an area of marshland. recently rain gardens and permeable paving
Enfield’s drainage network consists of a have been installed as part of highway works
separated foul and surface water system as and other projects.
well as a large number of open watercourses Local SuDS requirements
and drainage ditches. Most surface water Local Geology
sewers outfall directly into the nearest The bedrock geology in Enfield is
watercourse. predominantly London Clay. However, as
Consequently, a wide range of flood defence shown in the figure below, there are
systems are required to manage flooding significant superficial deposits of sand and
from all types of sources and ensure that gravel both in the hilly areas that make up
Enfield’s residents and businesses are not the western half of the borough and the
faced with unacceptable risks or disruption. flatter swathe of the Lee Valley that forms
Above ground SuDS play an important role in the eastern half – this area is dominated by
increasing the resilience of the drainage alluvial deposits of silt, sand, clay and gravel.
network, and improving water quality of Figure 2 - Bedrock and superficial
receiving watercourses.
deposits in Enfield
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Enfield Council SuDS D & E Guide © 2018 McCloy Consulting & Robert Bray Associates
