SNC-Lavalin Atkins 16x9 Template - City of Trees · Title: SNC-Lavalin Atkins 16x9 Template Author:...

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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

Transcript of SNC-Lavalin Atkins 16x9 Template - City of Trees · Title: SNC-Lavalin Atkins 16x9 Template Author:...

Page 1: SNC-Lavalin Atkins 16x9 Template - City of Trees · Title: SNC-Lavalin Atkins 16x9 Template Author: SNC-Lavalin Created Date: 7/4/2019 3:28:41 PM

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

Zorica Todorovic

3rd July 2019

SuDS in the City

Manchester

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

New build – opportunities/challenges, case studies

Retrofit – opportunities/challenges, case studies

Strategic approach

Conclusions

Content

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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?

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Infiltration

Attenuation (traditional or SuDS) with discharge to

• Watercourses

• Sewers

More green areas

Taking water back to its natural path

Why SuDS?

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Types of SuDS

Green/blue roofs Raingardens BioretentionBox raingardens

Swales Ponds Wetlands Tree pits

SoakawaysGravel pavementsFilter drainsPermeable pavements

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Amenity/Biodiversity Covers:

Aesthetic

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

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£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

Drivers

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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?

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Managing Water on Surface

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

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SuDS in the City?

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20, 50 , 100 years?

Infrastructure upgrade

Regeneration opportunities

New development

1)

Way to Resilient CitiesB

udget constr

ain

ts

Le

gis

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fra

me

wo

rk

Be

st p

ractice

2) Incremental opportunistic retrofit steps

Strategic solutions/Policy 3)

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SuDS in New Developments

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New Build – Low Density

Finberry, Ashford

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New Build – Medium Density

St Andrews Park, Uxbridge

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New Build – High Density

London's green

roof area reaches

1.5 million

square metres

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New Build – High Density

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

Mixed Use Development, Oldham Road…

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Regeneration Opportunities

Thames Water Twenty 4 Twenty

Battersea Nine Elms, London

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ManholesCatchpit ChambersPipesDrainage ChannelsGulliesFilter DrainsAttenuation TankFlow Control UnitSmart FilterGreen Roof Area

Regeneration Opportunities

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

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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

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SuDS Retrofit

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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

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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

investment

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

volume of water, £450k cost

Retrofit Residential

London Housing Estate, LBH&F

Source London.gov.uk

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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

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• 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

sequestered

• 54 Tonnes of air contaminates would be removed within 40

years

• 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

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Retrofit Roads

• Counters Creek, London, LNH&F

• Melina Road • Mendora Road • Arundel Gardens

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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

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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

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Retrofit Lessons Learnt

Difficult and costly to implement but necessary

No planning requirement to influence

Working in partnerships between range of stakeholders is

essential!

Lengthy stakeholders engagement process

No straight forward way to capture multiple needs

Different funding cycles for match funds

Incentives – funding mechanisms – Ignition project

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Strategic SuDS

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Linking Strategic Initiatives

Inform Planning and

Strategic Opportunities

Ignition

Natural

Course

UU SuDS

Maps

Manchester

LAP

Natural

Capital IP

MCC G&B

TGAP

• 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

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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

Conclusions