Page 101 - Updated SuDS Design & Evaluation Guide-Newham V3 Spreads

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Detailed Design 9.6.2 Distributed storage components the first component. 9.6.4 Single, tiered storage Detailed Design

components
This approach is useful for exploiting small
parcels of available space within the
Source control should be in place where
This can protect the functionality of
development and results in features, such as
flows are taken to an amenity play basin. In
downstream components as amenity spaces.
rain gardens and small basins which can be
this scenario, a tiered approach to storage is
The flow control opening for each
located close to buildings. These small
useful in order to maximize the usability of
component can be easily calculated and
features are usually sized for between the 1 in
features for general amenity, play or sports.
1 year and 1 in 10 year rainfall, with excess
passively move through subsequent storage
rainfall volumes conveyed along the
basin by creating wetland or any other
components without the requirement for
management train to site control. outflows from one storage component will Biodiversity can be introduced in the smaller
further storage. desired habitat.
This approach keeps subsequent storage More frequent rainfall events which produced This wetland basin at Fort Royal School can
store day-to-day rainfall whilst the much
components from regular wetting as around Raingardens, such as this wildflower raingarden at less runoff such as the 1 in 1 event, are larger basin in which it sits - defined by the
95% of rainfall events would be managed by St Paters School, Gloucestershire, are an excellent berm on the left of the photo - can store up to
example of the opportunities presented by prevented from covering the whole storage
distributing storage throughout a development. component by accommodating them in a the 1 in 100 volume.
smaller basin located within a more expansive
basin which can accommodate further Below: Excerpt of a detailed plan showing a
volumes of runoff up to the 1 in 100 event. As tiered basin with two levels (B & C) at a new
warehouse in Evesham. This example also
with other approaches the flow control can demonstrates the principle of distributed
be designed to manage the desired variable storage components with a planted
outflows at various depths of storage. raingarden (A) accommodating
up to the 1 in 10 rainfall event.
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9.6.3 Single, uniform storage Permeable forming a plaza outside Bewdley

components School Science Block.

Permeable pavements and blue-green roofs
which have relatively flat formations can store
all rainfall events up to the 1 in 100 year within
their footprint. In this scenario the flow

control would be designed to ensure that the
depth of stored flow discharged at the
respective 1 in 1 and 1 in 100 year greenfield
runoff rates.

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