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Surface Water Management for Resilient Cities GI/SuDS Opportunities and Challenges Zorica Todorovic 3 rd July 2019 SuDS in the City Manchester

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  • Surface Water Management for Resilient Cities GI/SuDS Opportunities and Challenges

    Zorica Todorovic

    3rd July 2019

    SuDS in the City


  • Sustainable surface water management - What is SuDS? Why we need SuDS?

    New build – opportunities/challenges, case studies

    Retrofit – opportunities/challenges, case studies

    Strategic approach



  • Half of the world’s population

    now live in cities and this will

    reach 60% by 2030

    and 75% by 2050

    Urbanisation puts huge environmental pressures

    Future Development Plans Urban Creep Climate Change System Ageing

    Increased costs of dealing with storm water

    • Need to

    • Reduce runoff volume

    • Reduce runoff rate

    • Mitigate diffuse pollution

    • Provide environmental benefits

    • Is there a better way?

    Why SuDS?

  • Infiltration

    Attenuation (traditional or SuDS) with discharge to

    • Watercourses

    • Sewers

    More green areas

    Taking water back to its natural path

    Why SuDS?

  • Types of SuDS

    Green/blue roofs Raingardens BioretentionBox raingardens

    Swales Ponds Wetlands Tree pits

    SoakawaysGravel pavementsFilter drainsPermeable pavements

  • Amenity/Biodiversity Covers:


    Ecological quality of the landscape

    Increased wellbeing

    Wildlife habitats

    Recreation opportunities

    Educational opportunities

    Water as a resource

    Increase in land values

    Decrease in deprivation areas

    Why SuDS?

    How developments could mimic natural flow patterns?

    Contributing to the quality of

    blue and green infrastructure

    Global trends – SW BMP, LID,

    WSUD, SuDS, Sponge Cities

  • £2.1billion

    The amount the UK government estimated could be saved in healthcare costs if

    every household in England were provided with good access to quality green space

    City Resilience

    Green Agenda

    Natural Capital

    Biodiversity Net Gain

    Reduction in Air Pollution

    Low Carbon Agenda

    Place Making


  • Standard of protection increases

    2, 5, 30 year storms

    100 year storms - allowance for climate change 40%

    Large attenuation tanks - flash floods

    How to manage flows?

    Why SuDS?

  • Managing Water on Surface

    Typical inlets in cities Could it be different – easier to maintain maybe more green

  • SuDS in the City?

  • 20, 50 , 100 years?

    Infrastructure upgrade

    Regeneration opportunities

    New development


    Way to Resilient CitiesB

    udget constr











    st p


    2) Incremental opportunistic retrofit steps

    Strategic solutions/Policy 3)

  • SuDS in New Developments

  • New Build – Low Density

    Finberry, Ashford

  • New Build – Medium Density

    St Andrews Park, Uxbridge

  • New Build – High Density

    London's green

    roof area reaches

    1.5 million

    square metres

  • New Build – High Density

    Manchester, Princess Street Manchester, Circle Square Apartment Block, Upper Chorlton Road

    Mixed Use Development, Oldham Road…

  • Regeneration Opportunities

    Thames Water Twenty 4 Twenty

    Battersea Nine Elms, London

  • ManholesCatchpit ChambersPipesDrainage ChannelsGulliesFilter DrainsAttenuation TankFlow Control UnitSmart FilterGreen Roof Area

    Regeneration Opportunities

    Circle Square, Manchester Old St Mary’s Hospital, Manchester Hardman Court, Manchester

  • New Build Lessons Learnt

    Planners need support in setting criteria - urban greening factor?

    Need for upfront planning for GI/SuDS as part of the development

    Procurement - cooperation of landscape and drainage

    Multifunctional spaces

    Inlets – attenuation - ease of upgrade and maintenance

    Clear maintenance/adoption route

    Planning – building control

  • 20

    SuDS Retrofit

  • Need for SuDS Retrofit

    Every location could be an opportunity

    Will they create the multiple benefits?

    • Neighbourhoods and streets will continue to be rejuvenated and enhanced

    • Roads resurfacing and sites refurbishments• Large extensions• Public buildings

    Major incentives and engagements required –

    commercial sites, schools, residents

  • Design and implement affordable and socially acceptable

    retrofit climate change adaptation measures in social

    housing landscapes.

    Support the achievement of wider GI goals

    Implement main measures through employment

    programmes for long-term unemployed and develop a

    set of training courses for maintenance professionals

    Develop a methodology for resident engagement

    Evaluate technical performance and social return on


    03.ha hard surfaces drained to SuDS, hold 110m3

    volume of water, £450k cost

    Retrofit Residential

    London Housing Estate, LBH&F


  • Retrofit Schools

    All Saints School, Newmarket

    Delivered in 4 months from inception to delivery

    1400m2 (equivalent to the size of over five tennis courts) of impermeable surface disconnected

    Saves 900m3 of water from being treated each year – enough to fill eight double decker buses

  • • Moorland School, Manchester

    • BITC project

    • Schools could save up to £1.75m a year for education budgets if all the city’s 1,300

    schools adopted similar measures

    • 85,000 Young people would benefit from access to green space

    • 4,000 Tonnes of carbon pa, equivalent to 1500 cars could be


    • 54 Tonnes of air contaminates would be removed within 40


    • 20,000 m2 of new green space would be created

    • 350 Swimming pools of water could be held by SuDS

    at any one time - 130,000 m3

    Retrofit Schools

  • Retrofit Roads

    • Counters Creek, London, LNH&F

    • Melina Road • Mendora Road • Arundel Gardens

  • Source Susdrain: I Titherington, CCC

    Retrofit Roads

    Removing 155,000sqm of impermeable area

    Releasing capacity for 6000-12,000 new homes

    Annual monetarised benefits of £250,000

    16,500sqm increase in green space

    400 additional trees

    • Grange Town, Cardiff

  • Source Susdrain

    Retrofit Public Realm

    • Shefield Grey to Green

    Peak inflow for the 1 in 30 year 60

    minute rainfall event is reduced from

    47.3l/s to 6.3l/s

    Peak inflow for the 1 in 100 year 60

    minute rainfall event is reduced from

    69.6l/s to 9.2l/s

    Peak inflow for the 1 in 100 year (+30%

    CC) 60 minute rainfall event is reduced

    from 92l/s to 12.1l/s

  • Retrofit Lessons Learnt

    Difficult and costly to implement but necessary

    No planning requirement to influence

    Working in partnerships between range of stakeholders is


    Lengthy stakeholders engagement process

    No straight forward way to capture multiple needs

    Different funding cycles for match funds

    Incentives – funding mechanisms – Ignition project

  • 29

    Strategic SuDS

  • Linking Strategic Initiatives

    Inform Planning and

    Strategic Opportunities




    UU SuDS





    Capital IP

    MCC G&B


    • Need for a strategic plan

    across areas to be

    implemented in stages as

    drivers (and funding)

    becomes available

    • This will result in holistic

    solutions in the long term

  • It’s the ‘right time’

    Planners need support in defining criteria – partnerships essential

    Systems need to be designed to meet multiple functions

    • Integrated approach in design – procurement of design services

    • Flexibility needs to be inbuilt in design

    • Need to attractive maintainable porous pavement materials

    • Ease of maintenance a paramount

    • Planning – building control

    Need for best practice and city’s standards

    Steep learning curve – pilots valuable evidence to build best

    practice for the City


  • Contact Details

    [email protected]

    [email protected]

    mailto:[email protected]:[email protected]