URBAN
Project funded
by theEU–DGEnvironment
L
andsurfacerelevant
forapplication
Artificial surface
Agriculture land
Forest and semi-natural areas
Wetlands
F
inancialcosts
(C
apital
,
operation
&
maintenance
)
Capital costs for filter strips can range between €3 and €30/m
2
filter strip area.
They vary considerably depending on the
design
of the filter strip and the use
of
substratematerials
such as gravel to increase the effectiveness of the filter
strip. Maintenance costs vary from €0.50-€6.50/m
2
filter strip area.
D
esign
Filter strips should be used as the
first stage of a SuDS
‘train’. They need to
be located immediately adjacent to their drainage area, and not in areas where
significant footfall is expected or where there is a risk of leaching contaminants
into groundwater. The maximum drainage length of a filter strip should be 50m,
and the minimum width 6m. To gain maximum water quality treatment, incoming
runoff should be distributed with a water depth of less than 50mm. Regular
inspection and
maintenance
is needed.
S
cale
Filter strips are suited to treating runoff
from small areas such as roads, roofs,
small car parks and other impervious
surfaces.
Filter strips are effective when receiving overland sheet
flow from an adjacent area.
Filter strips are uniformly graded, gently sloping,
vegetated strips
of land that provide opportunities for
slow conveyance
and (commonly)
infiltration.
They are designed to accept runoff as overland sheet flow from upstream development and often lie between a hard-surfaced area and a receiving stream, surface
water collection, treatment or disposal system. They are often used as a pretreatment technique before other sustainable drainage techniques. They can serve as
a buffer between incompatible land uses, and can provide localised groundwater recharge in areas with pervious soils.
Case studies: Drainagemanagement inHradecKralove,CzechRepublic; LeidscheRijn sustainableurbandevelopment,Netherlands
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