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
)
The construction cost of rain gardens will vary considerably depending on the
site
preparation
required and the
type of planting
selected. If the rain garden is
excavated and new growing media installed, costs will be much higher.A simple rain
garden constructed in a domestic garden will have little cost for the homeowner.
In contrast, rain gardens at the street level will require maintenance by municipal
authorities, although these are not expected to be onerous.
D
esign
Rain gardens are typically
small
and used at a property level. Minimum widths
of 3 m and length to width ratios of 2:1 will allow scattered planting of small
trees and shrubs and will facilitate operation and maintenance, although smaller
areas can also be used effectively. Native species should be carefully selected to
be able to withstand occasional
flooding
and prolonged inundation of the roots.
Rain gardens may be used as part of a wider
SuDS scheme
.
S
cale
Individual components of rain gardens
are designed to capture runoff from a
small surface area, for example a roof
or car park.
Rain gardens are small-scale
vegetated gardens
used for storage and infiltration. They are typically applied at a property level and close to buildings, for example to capture
and infiltrate roof drainage. They can use a range of components: grass filter strips, ponding areas, organic/mulch areas, planting soil, woody and herbaceous plants, sand beds. The
filtered runoff is either collected and returned to the conveyance system or infiltrated into the surrounding ground.
Case studies:Raingarden in theDayBrook,UK
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