Page 123 - Updated SuDS Design & Evaluation Guide-Newham V3 Spreads

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Detailed Design SuDS grass Meadow vegetation ■ and care to establish. Other mixtures are Detailed Design

Meadow vegetation has greater resilience to
SuDS grass describes the longer amenity
available where a drier or wetter grassland
dry conditions with less likelihood of lodging
grass used wherever water is likely to move
or flow, even minimally.
and offers amenity and biodiversity benefits
might be expected.
including habitat connectivity and visual
The addition of an annual cornflower mix
It is ideal for the immediate protection of any
interest.
can give a floral impact in year one.
flow areas.
The grass and herb species develop a much
Eventually this turf can be colonized by
native UK provenance seed.
wildflowers adapted to regular cutting but in
infiltration and evaporation losses. It
the first instance an amenity grass mix is greater root and leaf mass that assist both ■ ■ Meadow vegetation should comprise
provides very effective filtering and slowing
Usually a single cut, rake off and removal
often used as seeding or turf to cover the
of the flow of water as it passes through the of cuttings towards the end of September
surface of SuDS components before water grass profile. or early October is sufficient to keep the
flows across the surface. Suppliers tend to sward visually acceptable. Further cuts
offer standard species mixes although ■ The meadow mixture that is most useful can be carried out at other times of the
specific mixes can be purpose grown where where regular or occasional inundation is
year for specific visual or species
there is a lead in time of 10 or more weeks in expected is based on the MG5 grassland management.
the growing season. community (NVC classification). This
mixture is tolerant of both wet conditions ■ Autumn is the best time to seed as some
■ The grass is long enough to act as a filter
in winter and summer drought but as with meadow plants need cold weather to
but short enough to prevent ‘lodging’ all meadow grass habitat can require time break dormancy (cold stratification).
(lying flat under flow conditions) and so
Longer SuDS grass as a filter strip between
must be maintained between 75mm and paved surfaces and a raingarden.
117 150mm in height. 118

■ Turf can be laid in spring and autumn or
when weather conditions are suitable, for
instance in mild spells in winter or wet
weather in summer. Pegging the turf may
be necessary, with fully biodegradable
pegs, to prevent water flow lifting the
turves.

■ In dry weather a coir or jute mesh
covering a seeded surface can be used to
establish grass but there may be bare

patches to repair in the autumn. Facing: A seeded meadow in a ‘playful
raingarden’ at Renfrew Close Community
Raingardens, Newham.

Design Note:
This is best specified as turf as it is functional as soon as it is laid.

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