Page 29 - Updated SuDS Design & Evaluation Guide-Newham V3 Spreads

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In most locations the water table is likely to studies and LLFA detailed requirements can requires that greenfield runoff calculations site specific evidences and mitigation
Local SuDS requirements
be found at depths of less than 3 metres. be found on Newham webpage as below: should be performed using the IH124 method requirements provided to be evaluated by
Ground water source protection zones are LB Newham Flooding Webpage as supported by the HR Wallingford UK SuDS Newham Local Planning Authority.
found in the northern part of the borough. online greenfield runoff rate estimation tool. London City Airport guidance on biodiversity
Flood Risk and Sustainable Drainage: Under the same concern greenfield

Requirements and Guidance for Planning calculations should adopt the default and safeguarding
Application parameters (e.g. soil type) as provided by the Pre-planning advice
Newham Local Plan UK SuDS tool as characteristic of the Newham LLFA can provide pre-application Local SuDS requirements
application site location. advice for developments as part of a pre-
Newham LLFA drainage pro-forma
Newham LLFA will not object to greenfield application consultation agreement with
Highlights of main requirements: runoff calculations based on Flood Newham Local Planning Authority.

• All major development is required to Estimation Handbook (FEH) methodology, Please note that a fee specific to LLFA
Fig.5 Newham’s main made ground restrict post development runoff to provided that the results are demonstrated to services is required:
(grey/grey hatched) and source be largely consistent with IH124 methodology
protection zones (shades of pink) greenfield runoff rates unless it can be Pre-Application Advice Guidance Note &
demonstrated that site conditions prohibit output from UK SuDS online tool and Charging Schedule
The combination of these factors may limit the ability to do so. representative of the application site in a
potential for infiltration drainage. However, pre-development greenfield condition. LLFA advice can include providing specific
• All development must restrict runoff information on local flood risk, review of
given the high variability in ground conditions discharge within or to Critical Drainage Newham LLFA does not accept the following
found across the borough, it is recommended approaches: information provided by developer relevant
Areas (CDA) to greenfield rates or below. to the SuDS design and making
that developers carry out thorough ground N.B. there are 15 CDAs in Newham. • urban soil types for Greenfield runoff
investigations to establish the potential for estimation recommendations on compliance with local
and national policies.
23 infiltration. It should be noted that none of • Discharge to tidal water (i.e. River • applying urban catchment parameters to The above could be arranged by contacting 24
Thames, Lea and Roding) will need to
the above prevents use of SuDS within a
runoff estimation
development, if integrated into the design at take account of the effect of “tide Newham Planning Authority development.
an early stage. In any case, above ground no locking”, storm surge or submergence of Local LPA and Stakeholder Engagement control@newham.gov.uk
infiltration SuDS measures can still be used in the outfall, in order to prevent flooding. In addition to LLFA the Environment Agency Adoption of SuDS
areas of contaminated ground provided that An appropriate allowance in terms of and Thames Water must be consulted with
barriers to contain contaminants, such as onsite storage should be built into the concern of flood risk, discharge consents, Newham will not adopt SuDS unless
impermeable liners, are used to protect drainage strategy. building in proximity to flood defences undertaken by LB of Newham on council
groundwater. • Discharge to tidal water may not be structures and watercourses. owned land. Applicants should therefore put
restricted to greenfield provided scour/ London City Airport (LCY): Under concern of in place arrangements for maintenance and
Local SuDS specific requirements erosion would not result, however a level risk management (i.e. bird strike) LCY may end of life replacement of SuDS. Details must
be provided to the LLFA to add to its asset
Newham has developed a number of of attenuation will be expected - normally object to development proposal deemed register. There are other Risk Management
documents in connection with local flood risk a 1 in 30 attenuation - to create SuDS potentially to increase of bird presence in the Authorities, such as Thames Water or TFL
assessment and management. Main features that provide additional benefits. airport safeguard area. Whilst this concern that may be willing to consider adoption of
requirements applicable to major Application of Greenfield Runoff Rates should be heeded and early consultation with SuDS. Early engagement with the relevant
development are fully embodied in Newham’s To enable consistency of assessment City Airport is advised, LCY’s general concern party is critical to ensure their requirements
local policy (Newham Local Plan 2018). should never be used to scope out
between planning applications, Newham requirement of green infrastructures, such can be achieved.
Links to relevant Newham policy, flood risk LLFA, in its Statutory Consultee function,
SuDS, nor LCY’s objection accepted without

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