Page 29 - Newham SuDS DESIGN & EVALUATION GUIDE

be found at depth of less than 3 meter - at Links to relevant Newham Policy, flood risk Application of Greenfield Runoff Rates site specific evidences and mitigation
Local SuDS requirements
least seasonally. Ground water Source studies and further LLFA’s guidance (detailed requirements provided to be evaluated by
Protection Zones are found in the northern requirements) can be found on the Newham To enable consistency of assessment Newham Local Planning Authority.
part of the borough. Flooding webpage as below: between planning applications by London
Borough of Newham LLFA representatives, https://www.londoncityairport.com/
LB Newham Flooding Webpage use of default soil types for the actual site, corporate/Environment/biodiversity-and-
determined by HR Wallingford’s UKSuDS safeguarding
www.newham.gov.uk/localplan (Policy SC3)
online tool is the preferred approach. London Pre-Planning Advice: Newham provides
Flood Risk and Sustainable Drainage: Borough of Newham LLFA will not object to pre-application advice for developments as Local SuDS requirements
Requirements and Guidance for Planning Greenfield runoff calculations based on FEH part of a PPPA agreement. Newham LLFA

Application methodology providing that the results are can provide specific pre-planning advice as
largely consistent with IH124 methodology
Newham LLFA drainage pro-forma part of a PPPA or by direct agreement with
output from UKSuDS online tool and that the applicant. Please note that in either case a
Newham PAR HOST soil class used in the calculation can be
Fig.5 Newham’s main made ground (grey/grey demonstrated to be representative of the fee specific to LLFA is entailed. LLFA can
hatched) and source protection zones (shades Highlights of main requirements: provide applicants with information and
of pink) pre-development condition of the site. maps on topography, geology, flood risk,
• All major development is required to London Borough of Newham LLFA does not
The interplay of the above factors may limit greenfield runoff recommendations for SuDS
potential for infiltration drainage, however, restrict post development runoff to accept the following approaches: measures.
given the high variability in ground conditions greenfield run-off rates unless it can be • urban soil types for Greenfield runoff Adoption of SuDS
found across the borough, it is recommended demonstrated that site conditions prohibit estimation
to carry out thorough ground investigation the ability to do so. Newham will not adopt SuDS unless these
for all development to establish the potential • All development must restrict runoff • applying urban catchment parameters to are projects implemented by Newham on
23 for infiltration. discharge within or to Critical Drainage runoff estimation council own land. Applicants should 24
Areas (CDA) to greenfield rates or below. Local LPA and Stakeholder Engagement therefore put in place arrangements for
It should be noted that none of the above N.B. there are 15 CDAs in Newham.
prevents use of SuDS within a development if In addition to LLFA the Environment Agency maintenance and end of life replacement of
integrated in the design at early stage. Above • Discharge to tidal water (i.e. River and Thames Water must be consulted with SuDS. Details must be provided to the LLFA
ground, non-infiltration SuDS measures can Thames, Lea and Roding) will need to concern of flood risk, discharge consents, to add to their asset register. There are other
be used in areas of contaminated ground take account of the effect of “tide building in proximity to flood defences Risk Management Authorities such as
provided that barriers to potential locking”, storm surge or submergence of structures and watercourses. Thames Water or TFL who may be willing to
mobilisation of contaminates such as the outfall, in order to prevent flooding. consider adoption of SuDS. Early
impermeable liners or clay capping are used An appropriate allowance in terms of London City Airport (LCY): Under concern of engagement is required to ensure their
to prevent risk to groundwater. onsite storage should be built into the risk management (i.e. bird strike) LCY may requirements can be achieved.
drainage strategy. object to development proposal deemed
Local SuDS specific requirements potentially to increase of bird presence in the
• Discharge to tidal water may not be
Newham LLFA has developed a number of restricted to greenfield provided scour/ airport safeguard area. Whilst this concern
should be heeded and early consultation with
documents in connection with local flood risk erosion would not result, however a level
assessment and management. Main of attenuation will be expected - normally City Airport is advised, LCY’s general concern
should never be used to scope out
requirements applicable to major a 1 in 30 attenuation - to create SuDS
development are fully embodied in Newham’s features that provide additional benefits. requirement of green infrastructures, such
SuDS, nor LCY’s objection accepted without
local policy (Newham Local Plan 2018).

London Borough of Newham SuDS D & E Guide © 2018 McCloy Consulting & Robert Bray Associates London Borough of Newham SuDS D & E Guide © 2018 McCloy Consulting & Robert Bray Associates