SuDS in London - a guide

Movement of water from one location
to another.
Depositional environment
Describes the combination of physical,
chemical and biological processes
associated with sediment.
Design codes
Detailed guidance to influence the designs
of building and public realm; may be
enforced as a planning condition.
Design criteria
A set of standards agreed by the developer,
planners and regulators that the proposed
system should satisfy.
Designing for exceedance
An approach that aims to manage
exceedance flows during periods of heavy
rainfall, eg, the use of car parks during
extreme events.
Detention basin
A vegetated depression that is normally
dry except following storm events.
Constructed to store water temporarily to
attenuate flows. May allow infiltration of
water to the ground.
Detention pond/tank
A pond or tank that has a lower
outflow than inflow. Often used to
prevent flooding.
Diffuse pollution
Pollution arising from land use activities
(urban and rural) that are dispersed across
a catchment, or sub-catchment. This is
different from process effluent, municipal
sewage effluent, or an effluent discharge
from farm buildings.
Drain London
London Mayoral programme which helps
to predict and manage surface water flood
risk in London.
EA
The Environment Agency.
Ecology
All living things – such as trees, flowering
plants, insects, birds and mammals – and
the habitats in which they live.
Ecosystem
A biological community and its
physical environment.
Ecosystem services
The resources and processes that are
supplied by natural ecosystems.
Environment
Both the natural environment (air, land,
water resources, plant and animal life) and
the habitats in which they live.
Erosion
The group of natural processes, including
weathering, dissolution, abrasion,
corrosion, and transportation, by
which material is worn away from the
earth’s surface.
Evapotranspiration
The process by which the earth’s surface
or soil loses moisture by evaporation of
water and by uptake and then transpiration
from plants.
Everyday events
Events with a return period of less than
one year (100% chance of occurring in any
one year).
Exceedance
When heavy or extreme rainfall causes a
flow that is greater than the capacity of
the drainage system.
Extreme events
Events of greater than 30 year return
period (3.3% chance of occurring in any
one year). Can often lead to major flooding
with substantial damage.
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