From Green Belts to Blue Sieve - Rethinking London's Metropolitan Green Belt

From Green Belt to Blue Sieve Rethinking London’s Metropolitan Green Belt

Tatum S. Lau Masters of Science Community and Regional Planning + Masters of Science Urban Design The University of Texas at Austin

FROM GREEN BELT TO BLUE SIEVE

Copyright by Tatum S. Lau 2017

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TATUM LAU

RETHINKING LONDON’S METROPOLITAN GREEN BELT

From Green Belt to Blue Sieve Rethinking London’s Metropolitan Green Belt

Tatum S. Lau Masters of Science Community and Regional Planning (MSCRP) Masters of Science Urban Design (MSUD) Advisors Simon Atkinson, Ph.D., Allan Shearer, Ph.D., Katherine Lieberknecht, Ph.D The University of Texas at Austin

FROM GREEN BELT TO BLUE SIEVE

Acknowledgements

I would like to express my sincere gratitude to my advisors. Throughout my time at the University of Texas, my supervisor, Simon has challenged me to think beyond the limits of every idea, site and circumstance. Allan ensured that I applied creativity with rigor, and Katherine encouraged me approach big questions with clarity and conscientiousness. I am indebted to the enthusiastic and supportive faculty, staff and administrators at the School of Architecture.

In particular, I would like to thank Dean Almy, Liz Mueller, Sarah Dooling, Robert Young and Jonathan Ogren, whose classes have greatly contributed to the thinking that has shaped this work.

I would like to acknowledge those outside of my program and institution, who generously took the time to provide expert advice on topics incorporated into this study David Maidment at the School of Engineering, Erik Porse at the UCLA Institute of the Environment and Sustainability, Ryan Perkl at ESRI, and Julia Park at Levitt Bernstein Architects.

I would like to thank my previous academic mentors at London Metropolitan University, Robert Mull and Peter Carl, who taught me that being a student, is a lifelong journey, and encouraged me to embark on this one. I am appreciative of my colleagues at AECOM have been especially supportive, during a challenging six months. I wish to thank my peers, who have been both teachers and companions. I am grateful to my parents in Johannesburg, and in London, for their unwavering support. Last, my academic journey would not have been possible, or certainly not as meaningful, if it were not shared with my partner, Bara.

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TATUM LAU

RETHINKING LONDON’S METROPOLITAN GREEN BELT

Abstract

This study examines the effectiveness of the Metropolitan Green Belt (MGB), to understand whether or not, its benefits can be expanded to address the region’s current and future challenges. The region is considered ‘water stressed’, and demand already exceeds supply during dry years. The MGB is thought to exacerbate the problem of access to affordable housing, as it locks up the city’s surrounding land supply. At the same time, it is thought to deliver ecosystem services, such water and air purification. Current planning policy requires both the preservation of Green Belt land, and the provision of sites for development, based on assessed market needs.

The region’s unprecedented population growth, has resulted in conflicts in policy, leading to uncoordinated planning applications, for thousands of homes being approved all over the MGB.

This analysis suggests that the MGB, in its existing condition, does not have a significant green infrastructure network in place, however, at least 35% of the land area has the potential to protect the region’s water resources, if strategically restored and managed. The pilot project shows that incorporating WSUD principles into developments at an early stage, can contribute to the large-scale development of affordable and ecologically sustainable New Towns.

The study concludes with a strategic framework that shows how reform in regional governance and planning, could allow for both the provision of housing and jobs, as well as for the protection and enhancement of regional water-related ecosystems. It will provide a rationale for how planning authorities might co-ordinate development in the MGB, and explore issues that The study uses three primary methods to explore how the need to be considered when designing water sensitive MGB can accommodate development, whilst protecting developments on greenfield sites. and enhancing ecosystem services. The Natural Assets method uses Geographic Information Systems (GIS) to perform a green infrastructure analysis. GIS is also used to carry out spatial and hydrological analyses. A pilot study will simulate the Water Sensitive Urban Design (WSUD) conceptual design process, to understand the implications and benefits of this approach on green field developments in South East England.

FROM GREEN BELT TO BLUE SIEVE

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TA BL E O F CO N T E N TS

PART ONE: THE PROBLEM WITH THE GREEN BELT 01. INTRODUCTION............................................................................................................................................................ 10 02. LONDON’S 21ST CENTURY CHALLENGES...............................................................................................................17 2.1 A Brief History of Planning in the Region............................................................................................................................... 17 2.2 The Housing Crisis........................................................................................................................................................................... 18 2.3 A Looming Water Crisis............................................................................................................................................................... 22 03. THE PAST + PRESENT METROPOLITAN GREEN BELT.......................................................................................... 25 3.1 History.................................................................................................................................................................................................. 25 3.2 The Metropolitan Green Belt Today........................................................................................................................................30 3.3 The Benefits and Disbenefits.....................................................................................................................................................36 PART TWO: THE DEVELOPMENT OF THE BLUE SIEVE 04. FROM STOPPING TO PLANNING FOR GROWTH...................................................................................................43 4.1 Terms and Concepts.......................................................................................................................................................................43 4.2 Methods..............................................................................................................................................................................................49 4.3 Limitations, and implications for further research........................................................................................................... 57 05. REGIONAL ANALYSIS AND FINDINGS...................................................................................................................58 5.1 Identifying Regional Constraints...............................................................................................................................................58 5.2 Identifying Regional Opportunities........................................................................................................................................66 06. A WATER SENSITIVE URBAN DESIGN DEVELOPMENT.......................................................................................70 6.1 Preliminary Assumptions..............................................................................................................................................................70 6.2 Site Analysis...................................................................................................................................................................................... 72 6.3 Stormwater Assessment based on Land Use Scenarios................................................................................................. 81 6.4 Integrated Infrastructure Design.............................................................................................................................................84 PART THREE: THE METROPOLITAN BLUE SIEVE 07. CONCLUSION................................................................................................................................................................98 7.1 Discussion............................................................................................................................................................................................98 7.2 Proposed Indicative Strategies...............................................................................................................................................100 WORKS CITED...................................................................................................................................................................106 APPENDICES......................................................................................................................................................................110

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RETHINKING LONDON’S METROPOLITAN GREEN BELT

List of Tables Table 1: Distribution of Projected Seasonal Rainfall................................................................................................................. 23 Table 2: Agricultural Grades in the MGB.......................................................................................................................................34 Table 3: Research Methods................................................................................................................................................................49 Table 4: Natural Assets Method Data Process ..........................................................................................................................50 Table 5: WSUD Conceptual Design Process .............................................................................................................................. 53 Table 6: Hydrologic and Slope Analysis process...................................................................................................................... 53 Table 7: Storage Type and Functions ............................................................................................................................................54 Table 8: Storage Assessment Inputs and Outputs...................................................................................................................54 Table 9: Land Use and Impervious Cover Assumptions........................................................................................................56 Table 10: Area of Green Infrastructure Network.......................................................................................................................58 Table 11: Water Sensitive Areas.........................................................................................................................................................64 Table 12: Station proximity to WSAs or versatile soils............................................................................................................ 67 Table 13: Rail Stations for further study........................................................................................................................................ 67 Table 14: Characteristics of Potential Development Areas...................................................................................................69 Table 15: Open Space Standards for Central Bedfordshire Council................................................................................... 71 Table 16: Existing Land Cover in Developable Area.................................................................................................................80 Table 17: Spatial Requirements for WSUD BMP’s...................................................................................................................... 81 Table 18: Water Sensitive Urban Design Solutions by Scale Matrix.................................................................................... 91

FROM GREEN BELT TO BLUE SIEVE

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List of Figures Figure 1: Research Scope..................................................................................................................................................................... 12 Figure 3: Income and Real House Price Gap since 1961..........................................................................................................19 Figure 2: London’s historic and expected future growth.......................................................................................................19 Figure 4: Number of people commuting into London from surrounding Districts ...................................................20 Figure 5: Key Diagram from London Plan..................................................................................................................................... 21 Figure 6: Thames River Catchment Basin.................................................................................................................................... 23 Figure 7: John Claudius Loudon’s 1829 Plan............................................................................................................................... 25 Figure 8: Ebenezer Howard’s Garden City.................................................................................................................................. 25 Figure 9: London Council Country Proposals for a Green Girdle...................................................................................... 26 Figure 10: Green Girdle proposed by Raymond Unwin in 1933........................................................................................... 26 Figure 11: 1938 Green Belt Act........................................................................................................................................................... 27 Figure 12: Abercrombie’s 1944 Green Belt ................................................................................................................................. 28 Figure 13: Metropolitan Green Belt with motorways, rail and urban areas..................................................................... 31 Figure 14: Areas of Historic and Cultural Value in the Metropolitan Green Belt ......................................................... 33 Figure 16: Agricultural Classification Map.................................................................................................................................... 35 Figure 15: Land cover in Metropolitan Green Belt.................................................................................................................... 35 Figure 17: Approved Development proposals in the Metropolitan Green Belt............................................................. 37 Figure 18: A Comparison between Administrative and Functional Urban Areas........................................................39 Figure 19: Ecosystem Services..........................................................................................................................................................44 Figure 20: Core, edge and corridor................................................................................................................................................45 Figure 21: Water Balance..................................................................................................................................................................... 47 Figure 22: WSUD within Ecologically Sustainable Development Framework .............................................................48 Figure 23: Natural Assets Method.................................................................................................................................................... 51 Figure 24: Surface Water Storage Method as developed by HR Wallingford.............................................................. 55 Figure 25: Fragmenting Features.................................................................................................................................................... 59 Figure 26: Potential Green Infrastructure Cores........................................................................................................................61 Figure 27: Water Network..................................................................................................................................................................63 Figure 28: Water Sensitive Areas and ‘Threats’.........................................................................................................................65

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RETHINKING LONDON’S METROPOLITAN GREEN BELT

Figure 29: Opportunity Stations in the MGB.............................................................................................................................. 67 Figure 30: Development potential for selected sites..............................................................................................................68 Figure 31: Hydrologic Context.......................................................................................................................................................... 73 Figure 32: Strategic Context.............................................................................................................................................................. 75 Figure 34: Soils........................................................................................................................................................................................ 76 Figure 33: Topography......................................................................................................................................................................... 76 Figure 35: Land Cover.......................................................................................................................................................................... 77 Figure 36: Green and Blue Networks............................................................................................................................................. 78 Figure 37: WSUD Opportunities and Constraints..................................................................................................................... 79 Figure 38: Proposed areas for protection and development in the catchment........................................................... 79 Figure 39: Aerial photo of potentially developable area boundary..................................................................................80 Figure 40: Summary of scenario results......................................................................................................................................83 Figure 41: Overall Design Process...................................................................................................................................................85 Figure 42: Flow Direction Analysis.................................................................................................................................................86 Figure 43: Slope Analysis....................................................................................................................................................................86 Figure 44: Potential Detention Areas............................................................................................................................................ 87 Figure 45: Street Grid Layout............................................................................................................................................................88 Figure 46: Green Infrastucture Network......................................................................................................................................89 Figure 47: Blue Infrastucture Network at catchment and site scales............................................................................... 92 Figure 48: Water Treatment Process using BMP solutions................................................................................................... 93 Figure 49: Integrated Green, Blue and Grey Infrastructure.................................................................................................95 Figure 50: Catchment-based planning Units in Thames River Basin.............................................................................100 Figure 51: Blue Sieve Park System.................................................................................................................................................. 101 Figure 52: Metropolitan Strategic Framework......................................................................................................................... 103

FROM GREEN BELT TO BLUE SIEVE

01 .

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INTRODUCTION

London and the South East is experiencing a housing affordability crisis, to the detriment the environment, the economy and of the majority of Londoners. Between 1961 and 2014, Londoner’s real incomes have risen marginally, while real house prices have risen by five hundred percent (Quod & Shelter, 2016). In 2015, the median household income was £39,100 (Greater London Authority, 2015) – about half the required income to be eligible to apply for a subsidized, shared ownership flat (apartment). Homelessness is on the rise; young families have no choice but to leave, and businesses are at risk of becoming less competitive, since they can no longer retain young talent, who cannot afford housing (Quod, London First, & SERC, 2015). For the first time since 1939, London’s population surpassed its historical peak, with 8.63 million people (GLA Intelligence Unit, 2015).

Trends show that the population will continue to rise, and projections for 2050 range from 9.5 to 13.4 million people (Greater London Authority, 2014). Despite these issues, and projections for the future, the national and municipal government has been hesitant to take a proactive approach to address growth, resulting in a backlog of homes and the need to build 60,000 per year for the next ten years (Bennie, 2015).

The Metropolitan Green Belt (MGB), as we know it today, has been in place for over 60 years, and was formally adopted in 1955 with the primary purpose, to prevent uncontrolled expansion of the city. The MGB prohibits development around Greater London, thereby locking up the city’s land supply. For the reasons stated, and others, the MGB has become a topic of vehement debate amongst academics, politicians and the general public. Several institutions are now calling for reform of Green Belt policy. A study by the London School of Economics found that ‘there has been continual incremental change, and the absence of an overall plan for change has led to piecemeal development in the MGB’ (Mace, Blanc, Gordon, & Scanlon, 2016, p. 5). Advisors to the national government, on issues of the environment are calling for, a refresh of Green Belt policy to see how it might evolve to fit twenty first century circumstances and deliver more positive benefits for the natural environment and people’s enjoyment of it (Natural England, 2008).

A perspective shared by organizations like Natural England, and the Campaign to Protect Rural England (CPRE) is, that Green Belts play a role in delivering ecosystem services to the region. Ecosystem services are ‘the benefits people obtain from ecosystems. These include provisioning, regulating, and cultural services that directly affect people and supporting services needed to maintain the other services’ (MEA, 2003, p. 49).

This is particularly important in the context of climate change. The projected impacts of climate change on the region are, hotter, drier summers, wetter winters, and more frequent tidal surges (Greater London Authority, 2016). London and the Lower Thames has the highest concentration and number of people in the country, yet the Thames River Basin receives below national average rainfall (Environmental Agency & Defra, 2015). Water consumption already outstrips water supply during dry years (Greater London Authority, 2016). In summary, climate change will increase the vulnerability of a region already water stressed.

The MGB holds the discussed planning conflicts in tension. On one hand, it is thought to exacerbate the problem of access to affordable housing but on the other, it is thought to deliver nature’s basic services, such water and air purification, food production and flood mitigation. The region has an invaluable resource - a largely protected expanse of land almost three times the size of Greater London. Today, this resource is at risk and is being eroded by uncoordinated development, a phenomenon which is unlikely to stop, given the growing population.

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TATUM LAU

The purpose of this study is to reflect on the effectiveness, condition, policy and limitations - of what is considered to be one the most successful planning tools of our time – to understand whether or not, its benefits could be expanded to address the region’s current and future challenges.

Additionally, this study seeks to open up a polarized debate. The debate is divided between, industrialists, the business community and social housing advocates, who are calling for the release of green belt land for housing, while environmentalists, and rural and agricultural communities argue that the green belt provides recreational resources and ecosystem services including food, clean air and water. There are of course, more than two agendas, but either way, politicians don’t want to dismantle, that which is considered to be the keystone of British planning.

The literature suggests that the MGB ‘is already making [an ecological] contribution, which could have even a greater significance in the future if it is managed effectively’ (Natural England & Campaign to Protect Rural England, 2010, p. 7). The MGB covers 5160 square kilometres in the region, but little seems to be known about whether, and to what extent it is making a contribution. This study makes a contribution to the debate by using contemporary tools and methods to identify parts of the MGB that provide ecosystem services. Additionally, using a pilot study, it examines how ‘Water Sensitive Urban Design’, a new approach to development, can mitigate its impact on ecosystem services.

The study will show how reform in regional governance and planning, could allow for both the provision of housing and jobs, as well as for the protection and enhancement of regional water-related ecosystems. It will provide a rationale for how planning authorities might co-ordinate development in the MGB, and explore issues that need to be considered when designing water sensitive developments on greenfield sites.

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RETHINKING LONDON’S METROPOLITAN GREEN BELT

The study uses three primary methods to explore how London’s Metropolitan Green Belt can accommodate development, whilst protecting and enhancing ecosystem services for the region. The Natural Assets method uses the Environmental Systems Research Institutes (ESRI) Geographic Information Systems (GIS) to perform a green infrastructure analysis. GIS will also be used to carry out spatial and hydrological analyses. A pilot study will demonstrate how a Water Sensitive Urban Design (WSUD) conceptual process might be used in the MGB. The study utilizes spatial and tabular data, collected from public agencies or open source databases. The methods are rooted in literature from green infrastructure planning, and water resources management. Green infrastructure refers to ‘an interconnected network of multifunctional greenspaces that are strategically planned and managed to provide a range of ecological, social, and economic benefits’ (Matthews, Lo, & Byrne, 2015, p. 156). Green infrastructure has been found to contribute towards ecosystem health, which in turn contributes towards human health and well-being (Tzoulas, 2007).

This study has been delimited to the impacts of development on water-related ecosystems in the Metropolitan Green Belt. Although the housing crisis is a central concern, and the catalyst for this study, it is a broad and complex topic that needs exploring on various fronts. Recent studies (AECOM, 2015; Quod & Shelter, 2016) suggest a range of strategies, of which the Green Belt is one, that should be explored in more detail (Figure 1). Ecosystem services encompass a wide range of environmental and cultural services, however this study focusses on water-related regulating services.

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FROM GREEN BELT TO BLUE SIEVE

EXPANDED HUB AIRPORT NEW TOWNS 100K TALL BUILDINGS

GARDEN CITIES

REGIONAL HOUSING STRATEGIES

ESTATE REDEVELOPMENT DENSIFY THE SUBURBS

PRIMARY PRODUCTION FOOD FRESH WATER WOOD + FIBER FUEL

HIGH DENSITY TOWN CENTRES

WATER PURIFICATION

LONDON REGIONAL BOARD

DISEASE REGULATION AESTHETIC SPRIRITUAL EDUCATIONAL

CULTURAL

NATIONAL HIGH SPEED RAIL

REGULATING

FLOOD REGULATION

REGIONAL TRANSPORT AUTH.

ECOSYSTEM SERVICES

CLIMATE REGULATION

REGIONAL CITY NETWORK

TRANSPORT CORRIDORS

PROVISIONING

GREEN BELT

SOIL FORMATION

SUPPORTING

NUTRIENT CYCLING

RECREATIONAL

Aecom, 2015; Quod + Shelter, 2016

MEA, 2005

Figure 1: Research Scope (GLA, 2014)

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London’s housing crisis is a constantly evolving issue in the region. This study was initiated in summer of 2016, when Sadiq Khan, London’s new Mayor was elected.

Affordable housing was on the top of his priority list, and he has since launched a consultation draft of a new housing strategy, due to be published in 20181. The strategy has not been incorporated into this document, but as this study later explains, new plans for the city will not necessarily address the issues occurring beyond Greater London.

RETHINKING LONDON’S METROPOLITAN GREEN BELT

Part three ‘Redefining the role of Green Belts’ distils the content of the report, through a discussion of the results in relation to the literature and policies. It provides with an answer to the research question,

How should Green Belt policy be reformed, in order for the London region to better respond to 21st century challenges like housing and climate Part one of this report provides background and context crises?,

to the study. Chapter 2 discusses current and future planning issues in the London Metropolitan region. showing that Green Belt policy is just one part of a larger Chapter 3 presents a historical review of Green Belts, vision for the future of the region. as they evolved from an idea into policy. It discusses the current state of the MGB, and conflicts in policy that have led to development proposals being approved on the Green Belt today. Part two makes the case for what will be referred to as ‘the Metropolitan Blue Sieve’. It draws on landscape and urban water management literature, to setup an argument for an alternative approach to Metropolitan planning, based on the evolution of sustainability thinking. Chapter four summarizes the approach and methods used in the study. The methods are applied in chapter five and six, which illustrate a planning process using a regional green infrastructure analysis and Water Sensitive Urban Design conceptual design process.

1 https://www.london.gov.uk/what-we-do/housing-andland/have-your-say-tackling-londons-housing-crisis

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FROM GREEN BELT TO BLUE SIEVE

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RETHINKING LONDON’S METROPOLITAN GREEN BELT

PART I

The Problem with the Green Belt

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02 .

RETHINKING LONDON’S METROPOLITAN GREEN BELT

LO N D O N ’ S 21 ST C ENTURY CH ALLENGE S

2.1 A Brief History of Planning in the Region The Housing and Town Planning Act of 1909 is ‘recognized as the beginning of modern statutory planning’ (Thomas, 1963, p. 15) and enabled local authorities to prepare town plans. The Act of 1919 allowed local authorities to combine their plans - forming the beginning of regional planning in England. The Greater London Regional Planning Committee was established in 1927 with town planner, Raymond Unwin as its Technical Advisor. Unwin produced two plans for London in 1929 and 1933 respectively, and although they were not formally adopted, many of his ideas were incorporated into the London County Council’s (LCC) program (Thomas, 1963). Regional plans on behalf of the Standing Conference on London Regional Planning were produced in 1944 (Abercrombie, 1944) and 1970 (South East Joint Planning Team, 1970).

Outside of London, regional plans were produced by elected regional assemblies until 2011, when they were abolished by the coalition government. The 2011 Localism Act put an end to regional planning in England and Wales, devolving decision-making powers to local governments and communities, which in turn ‘has weakened the ability of democratically elected local planning authorities to plan strategically’ (Bowie, 2016, p. 62). Three remaining legal mechanisms facilitate the coordination of strategic planning between local authorities. First, local authorities have a ‘duty to cooperate’, but not necessarily a ‘duty to agree’ (Department for Communities and Local Government, 2011) when producing local plans. Second, two or more local authorities can voluntarily submit joint local plans and carry out strategic planning together. Third, Local Enterprise Partnerships (LEPs) may be formed between Margaret Thatcher’s government abolished the Greater local authorities and representatives of businesses, London Council (GLC) in 1986 and municipal powers although these voluntary organizations are not granted were devolved to local authorities. Following a public planning powers (Bentley & Pugalis, 2013). referendum in 1998, London got its first Mayor and the Greater London Authority (GLA), formed in 2000. Today, one of the responsibilities of the Mayor is spatial planning for Greater London, guided by the London plan, the city’s key strategic 25-year plan. Local authorities are responsible for writing their own plans but must comply with the London plan. The National Planning Policy Framework (NPPF) (Department for Communities and Local Government, 2012) is the guiding document for local authorities on how to develop local plans and make decisions about planning applications. These two documents will be referred to throughout this study.

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2.2 The Housing Crisis South East England’s population has been growing since the 1980’s. Historically, London’s population peaked in 1939 at 8.61 million people and in 2015, the population was estimated to be 8.63 million (GLA Intelligence Unit, 2015) surpassing the historical peak for the first time.

Figure 2 shows the projected population to be between 9.5 to 13.4 million by 2060. Employment continues to rise and is projected to increase by 860,000 jobs between 2011-2036 (Bennie, 2015).

The housing crisis has disproportionate impacts on the quality of life for working and middle-class households.

Impacts include instability for low to medium income households who rely on the unregulated private rental market. Shelter estimates that 150 families become homeless daily (Shelter, 2016). A 2015 study showed that the number of people whose commute to work exceeded 2 hours had increased by 72% in 10 years (The Guardian, 2015). Figure 4 shows the number of people per district (outside the Greater London region) Population growth is one reason, amongst many, that commuting into London. the region is experiencing an affordable housing crisis.

Real incomes are barely increasing, yet real house prices The lack of affordable housing in the region also has have more than doubled over the last 20 years, while negative economic impacts. A 2015 study found that the decrease in house building by both the public and London is at risk of losing sections of its workforce due to private sector make matters worse (Figure 3). In 2015, rising housing costs, and that ‘three-quarters of business the median household income was £39,100 (Greater decision makers surveyed warned that London’s housing London Authority, 2015) – about half the required supply and costs are a significant risk to the capital’s income to be eligible to apply for a subsidized, shared economic growth’ (Quod et al., 2015, p. 6). ownership flat (apartment) in the Borough of Hackney2.

Since 2000, between 20–25,000 homes were built in Greater London annually. Based on 20-year population projections, it is estimated that 40,000 homes need to be built annually – and if the city were to catch up with the backlog, 62,000 homes would need to be built annually between 2015 to 2025 (Bennie, 2015).

2 The shared ownership scheme was designed to help low to middle income, first-time buyers, to purchase a portion of a property from a Housing Association. This particularly case was based on a unit being sold by the Islington and Shoreditch Housing Association (Osborne, 2015).

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A . LONDON’S FIRST LONG-TERM INFR ASTRUCTURE PLAN

LONDON INFRASTRUCTURE PLAN 2050 PAGE 8

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RETHINKING LONDON’S METROPOLITAN GREEN BELT

POPULATION (MILLIONS) 15 14 13

High 13.4 million

Within the coming few months we expect to surpass London’s 1939 population peak of 8.6 million

12 11 10

Central 11.3 million Low 9.5 million

9 8 7 6 5 4 3 2

WHEN BROWNFIELD ISN’T ENOUGH 1820

1800

ummary

essing issue

sinesses, public rs themselves

1840

1860

1880

1900

STRATEGIC OPTIONS 1940 1960 1980 2000 FOR 2020 LONDON’S 2040 2060 GROWTH

1920

Figure 2: London’s historic and expected future growth (Greater London Authority, 2014)

FIGURE 1

LONDON’S HISTORIC AND EXPECTED FUTURE GROWTH Source: GLA Intelligence Unit

House building in London since 1961

nsequences of hat means the

London County Council

e now costs more

Labour

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Desmond Plummer

Labour

Sir Reg Goodwin

£450,000

age London

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Ken Livingstone

Labour

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Boris Johnson

45,000

In 2012, there were 15 million international visitors to London.

Real house price This number is forecast to increase to around 21 million by 2022.

40,000

£350,000

with rent, bringing

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Conservative

Sir Horace Cutler

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1981

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1985

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1969

1965

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Figure 3: Income and Real House Price Gap since 1961

idening gulf between salaries and house prices, 2 September 2015, based on Land Registry and HMRC data.

2015 (p.26); GLA, The London Strategic Housing Market Assessment, 2013. The SHMA assesses that if London is to meet its long twenty years then the figure is 48,840 homes per year, but if it is to meet need within a decade then the annual requirement is 62,000. completions in 2014/15 were 18,260.

(Quod & Shelter, 2016)

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When brownfield isn’t enough

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FROM GREEN BELT TO BLUE SIEVE

The city’s approach to deal with growth has primarily been to redevelop brownfield sites. This approach has been criticized by the authors (Quod & Shelter, 2016) who suggest that London has no significant derelict land and that the term ‘brownfield’ is misunderstood.

Brownfield sites in London’s context, are those that have previously been developed. They are typically residential, institutional and industrial sites that have the potential for redevelopment, but all require negotiation, which can be a lengthy and complex process. Figure 5 illustrates the brownfield sites as ‘Opportunity Figure 6: Districts to London areas’, which are estimated to accommodate 303,000 new homes. Intensification Areas are those that have access to existing transportation and are estimated to accommodate 8,650 new homes (Greater London Authority, 2016). The city is also investing £86 billion3 Figure 6: Districts to London on two major transportation projects (Crossrail 2 and High Speed 2) over the next 15 years to improve local and regional access.

The National government announced their support for new ‘locally-led garden towns and villages’ in a recent whitepaper (Department for Communities and Local Government, 2017a). A Garden Village is defined as a development with between 1,500 – 10,000 new homes and a Garden Town, as a development with over 10,000 Commuting in new homes. The government committed to providing £7.2 million to 14 new Garden Towns and Villages (Department for Communities and Local Government, 2017b). New legislation will allow local councils to form New Town Development Corporations as a mechanism to deliver large scale, council-led developments.

Commuting in Lon

3 Crossrail 2 is estimated to cost £30 billion (Crossrail2, 2017) and High Speed 2 £56 billion (BBC, 2016)

Figure 4: Number of people commuting into London from surrounding Districts (GLA Intelligence Unit, 2014) 20

Top areas for commuting out of London

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RETHINKING LONDON’S METROPOLITAN GREEN BELT

Key Diagram

Central A (2.10 - 2 Inner Lo

London - Stansted - Cambridge - Peterborough Corridor

London - Luton Bedford Corridor

Outer Lo

Metropo

Opportu

Areas fo

Strategi Develop LLDC Ar

Central Activities Zone (2.10 - 2.12) Inner London (2.9)

- Peterborough Corridor

ton ridor

Outer London (2.6 - 2.8) Metropolitian Centres (2.15)

Opportunity Areas (2.13) Areas for Intensification (2.13)

86

Central Activities Zone (2.10 - 2.12) Inner London (2.9)

Stratford

Regeneration Areas (2.14)

Wandle Valley Regional Parks Opportunities

Outer London (2.6 - 2.8)

Regional Parks (2.18)

Thames

Gateway Metropolitian Centres (2.15)

(2.18) Green Belt & Metropolitian Open Land (2.18) Regional Coordination Corridors (2.3)

Opportunity Areas (2.13) Areas for Intensification (2.13)

86

Strategic Outer London Development Centres (2.16) LLDC Area (2.4)

Central Activities Zone (2.10 - 2.12) Inner London (2.9)

Regeneration Areas (2.14) Regional Parks (2.18)

Outer London (2.6Thames - 2.8)

Wandle Gateway Metropolitian Centres (2.15) Valley

Regional Parks Opportunities (2.18) Green Belt & Metropolitian Open Land (2.18) Regional Coordination Corridors (2.3)

Opportunity Areas (2.13) Areas for Intensification (2.13) Strategic Outer London Development Centres (2.16) LLDC Area (2.4) Regeneration Areas (2.14)

Thames 21 Gateway

Regional Parks (2.18) Regional Parks Opportunities (2.18) Green Belt & Metropolitian Open Land (2.18)

T H E LO N D O N P L A N M A R C H 2 0 1 6

ratford

National Growth Areas (2.3)

Ó

Main Airports (6.6) Crossrail 1 (6.4) Crossrail 2 Metro (6.4) Crossrail 2 Regional (6.4) High Speed 2

T H E LO N D O N P L A N M A R C H 2 0 1 6

sted - Cambridge ough Corridor

Strategic Outer London Development Centres (2.16) LLDC Area (2.4)

T H E LO N D O N P L A N M A R C H 2 0 1 6

Western Wedge London - Stansted - Cambridge

Regener

86

Stratford

Regiona (2.18) Green B Open La Regiona Corridor

Nationa

Ó

Main Air

Crossrai

Crossrai

Crossrai

High Sp

Thames London

National Growth Areas (2.3)

Ó

Regiona

Thames Gateway

Main Airports (6.6) Crossrail 1 (6.4) Crossrail 2 Metro (6.4) Crossrail 2 Regional (6.4) High Speed 2

Thameslink (6.4) London Overground (6.4)

Figure 5: Key Diagram from London Plan (Greater London Authority, 2016)

MASTERS DESIGN REPORT

FROM GREEN BELT TO BLUE SIEVE

2.3 A Looming Water Crisis

Water Supply

The combination of population growth and climate change on the regions natural resources, and water in particular, is becoming increasingly evident. Issues related to water supply, quality, and flooding are all of growing concern. The projected impacts of climate change are increased temperatures, increased winter rainfall, decreased summer rainfall, and more frequent tidal surges (Greater London Authority, 2016). Table 1 shows the projected changes in summer and winter monthly rainfall for 2020, 2050 and 2080.

London and the Lower Thames has the highest concentration and number of people in the country, yet the Thames River Basin receives 690mm of rainfall, which is below the national average of 897mm (British Geological Survey, n.d.). The basin includes Greater London and other large urban areas including Luton, Reading and Guildford. Figure 6 shows the Thames River Basin and its tributaries. 60 - 70 per cent of London’s water supply is from surface water from the River Thames and River Lee. Most of the water is taken upstream of Teddington Weir and stored in reservoirs in proximity to Greater London. 30 - 40 per cent of London’s water supply is abstracted from the chalk aquifer (Environmental Agency & Defra, 2015). Water consumption already outstrips water supply during dry years (Greater London Authority, 2016) and South East England is classified as ‘seriously water stressed’ (Environmental Agency, 2008).

Temperature and rainfall change will increase the intensity and effect of heat waves, urban heat island effect, flood risk and drought. During the 2003 heatwave, 600 people died as a result of overheating. The Urban Heat Island (UHI) effect results in the city being as much as 8°C warmer than surrounding areas, such as those in the Green Belt (Greater London Authority, 2016).

The following sections describe the regions specific London relies on private water companies for its supply. water related issues and ways in which the issues are They identified seven strategies to increase supply being addressed: including increasing abstraction and desalination4.

Thames Water began operating a desalination plant in • Water Supply Beckton in 2010 and this is the primary reason why the supply zone is not at a deficit. Although these strategies • Water Quality are helping with water shortages, they have longer term implications on energy use and environmental health. A • Flood Risk desalination plant requires the same amount of energy that would power 8,000 homes and the GLA found that ground water abstraction is the reason low flow levels in the summer (Greater London Authority, 2011).

4 The other five include ‘increasing reservoir capacity, wastewater treatment, raw water transfers, groundwater recharge and international import of water from Norway’ (Greater London Authority, 2011, p. 42)

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Year

RETHINKING LONDON’S METROPOLITAN GREEN BELT

Decrease summer rainfall (%)

Increase winter rainfall (%)

Mean summer rainfall (mm)

Mean winter rainfall (mm)

2017

n/a

n/a

50.30

51.00

2020

0.06

0.06

47.30

54.06

2050

0.18

0.15

41.30

58.65

2080

0.22

0.22

39.30

62.22

Table 1: Distribution of Projected Seasonal Rainfall (Climate-Data.org, n.d.; Defra, 2009)

BVe &# AdXVi^dc VcY ZmiZci d[ i]Z I]VbZh 8;BE

Figure 6: Thames River Catchment Basin (Environmental Agency & Defra, 2015)

23

MASTERS DESIGN REPORT

FROM GREEN BELT TO BLUE SIEVE

Water Quality

Flood Risk

Poor water quality is an issue in both urban and rural areas within the Thames River Basin. At the city scale, combined sewer overflows (CSOs) are of the primary causes of poor water quality.

The change in rainfall distribution, increased intensity and increased frequency of tidal surges puts 2.65 million people and £200 billion worth of property at risk to coastal, fluvial and surface flooding (Environmental Agency, 2012; Greater London Authority, 2014). Surface Discharges occur at some CSOs between 50 to 60 flooding is made worse by impervious cover in urban times each year. Widespread heavy rainfall can areas, and lack of attention to rainwater harvesting. lead to over a million tonnes of untreated sewage and rainwater legally discharging directly into the The Environmental Agency has plans across multiple rivers. Despite much improvement in the Thames scales to address flood risk. The Thames Estuary 2100 this is clearly unacceptable in the 21st century and (Environmental Agency, 2012) is a flood adaptation and contravenes the Urban Waste Water Directive that requires all wastewater to be treated before it is mitigation plan till the end of the century, which proposes discharged (Greater London Authority, 2011, p. 17). options including new flood barriers, storage dams and flood walls to address tidal flooding and storm surges. £4.2 billion is being invested over 7 years, towards the Management plans at the catchment scale provide construction of a 25-km long storage and transfer tunnel guidance on adaptation measures to local authorities below the River Thames. The tunnel and new sewage and districts. At the local scale, policies in support of treatment works will prevent discharge into the river Sustainable Urban Drainage Systems (SUDS), which ‘seek to mimic natural drainage, managing more water and recover energy from the sludge (Tideway, n.d.). closer to the source, in order to reduce the volume and Within England, only 17% of surface water bodies’ speed of waters flowing into sewers and watercourses ecological status are considered ‘good’ or ‘better’, after storms’ have been adopted to mitigate surface compared to 53% of ground water bodies, based on the flooding (Greater London Authority, 2011, p. 84).

EU’s Water Framework Directive regulations, which evaluate quantitative and qualitative indicators.

The most significant factors that negatively affect water bodies in the Thames River basin are physical modifications to rivers (44%), pollution from wastewater (45%), pollution from towns, cities and transport (17%), changes to the natural flow and level of water (12%) and pollution from rural areas (27%) (Environmental Agency, 2015; Environmental Agency & Defra, 2015).

The Environmental Agency, a non-departmental public body have designated drinking water ‘safeguard zones’ for surface and ground water. Although these zones are non-statutory, the Environmental Agency partners with water companies in an effort to meet the water quality objectives of the EU’s Water Framework Directive (Environmental Agency & Defra, 2015).

24

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03.

RETHINKING LONDON’S METROPOLITAN GREEN BELT

THE PAST + P R E S E NT M E TRO P O LITAN GRE EN BELT

3.1 History Origins of the Idea

In 1580, Queen Elizabeth I adopted a ‘cordon sanitaire’, which would prevent development within a three-milewide zone around London. The rationale was that the separation would prevent the plague from spreading (Halliday, 2013). The association between public health and open space was picked up again almost two centuries later, when landscape planner John Claudius Loudon proposed concentric country zones in an article entitled ‘Hints for Breathing places for the Metropolis’ (Loudon, 1829).

Ebenezer Howard was the leader of the Garden City Movement, and perhaps the most recognized of the early Green Belt proponents. At the beginning of the twentieth century, Howard advocated for ‘belts of country’, in response to rapid urbanization and the loss of rural, agricultural land. Central to the idea of the Garden City was the separation of ‘town’ from ‘country’, or urban from rural (Howard, 1902).

Figure 7: John Claudius Loudon’s 1829 Plan (Loudon, 1829)

Figure 8: Ebenezer Howard’s Garden City (Howard, 1902)

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FROM GREEN BELT TO BLUE SIEVE

MASTERS DESIGN REPORT

Planning Green Belts

Between 1889 and 1965, the London County Council (LCC) was the principle administrative body for the County of London5, responsible for the co-ordination of local planning between authorities. In 1901 and again in 1911, the LCC, proposed a ‘green girdle’ around London (Figure 9). In a 1933 report to the Greater London Regional Planning Committee, Raymond Unwin expanded on the LCC’s ideas by proposing larger (but not necessarily continuous) parkways around London (Figure 10).

In 1935, the LCC began a Green Belt Scheme to provide accessible recreational areas to urbanized parts of London. It provided land acquisition grants to local councils for up to half the cost of the land. Three years later, the Green Belt Act was passed (Figure 11), which allowed land acquired by the counties to be permanently protected (Thomas, 1963).

Patrick Abercrombie, a city planner closely affiliated with the Council for the Preservation of Rural England (CPRE) was asked to produce Greater London’s first Regional Plan. His Green Belt would provide access to recreation but, like Howard, Abercrombie was concerned about the separation of urban from rural.

Figure 12 illustrates Abercrombie’s proposal for a continuous belt, up to 10 miles wide in some parts, which covered a considerably larger area than his predecessors.

His strategy for land acquisition also differed to Unwin’s in that funding would be used to purchase development rights from landowners or leaseholders. The Green Belt is described in the plan:

Figure 9: London Council Country Proposals for a Green Girdle (Thomas, 1963)

with its open lands and running streams used for recreative purposes, and acting as a barrier to the continuous expansion of London, should not provide, even in its inhabited parts, for the large scale building which, as described later on, will be necessary in connection with decentralisation.

(Abercrombie, 1944, p. 26) Figure 10: Green Girdle proposed by Raymond Unwin in 1933 5 The County of London is now known as Inner London.

The LCC later become the Greater London Council (1965 – 1986) and is currently called the Greater London Authority (GLA).

(Adapted from Thomas, 1963)

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RETHINKING LONDON’S METROPOLITAN GREEN BELT

Figure 11: 1938 Green Belt Act (The Building Centre, 2016) 27

MASTERS DESIGN REPORT

FROM GREEN BELT TO BLUE SIEVE

Abercrombie’s proposals intentionally incorporated strategies for the decentralisation of London, aligned with recommendations from the Barlow Commission following World War 2. The first wave of New Towns were also part the decentralization strategy. These were government funded, large-scale communities located away from Metropolitan areas, created to disperse and rehouse the nation after the war.

Green Belts were formally adopted into policy in 1955, for the first time. The 1947 Town and Country Act required local authorities to prepare development plans specifying the location of new land uses, thereby enabling Green Belts to be incorporated into local plans.

Despite over three centuries of an evolution of the idea that recreational green space benefits quality of life and public health, circular 42/55 defined the Green Belt as nothing more than a growth stopper.

The purpose of Green Belts was defined, To check the further growth of large built up areas To prevent neighbouring towns from merging into one another To preserve the special character of a town Inside a Green Belt, approval should not be given, except in very special circumstances, for the construction of new buildings or for the change of use of existing buildings for purposes other than agriculture, sport, cemeteries, institutions standing in extensive grounds, or other uses appropriate to a rural area’ (Ministry of Housing and Local Government, 1955, p. 1)

Figure 12: Abercrombie’s 1944 Green Belt (Thomas, 1963)

Agricultural, recreational and environmental uses were of course amenable to Green Belt policy; however, the removal of this language would later influence how the Green Belt would be managed and evaluated.

It should be noted that around the same time, other environmental policies were being adopted. The 1949 National Parks and Countryside Act enabled National parks and Areas of Outstanding Natural Beauty (AONB) to be designated, and areas within Green Belts were selected for additional protection.

Green Belt policy was updated in 1988 by Planning Policy Guidance 2 (PPG2)6, to incorporate the objectives of ‘sustainable development’. The ‘purpose’ of Green Belts was slightly modified and ‘secondary objectives’ were added:

6

PPG 2 was revised again in 1995 and 2001

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RETHINKING LONDON’S METROPOLITAN GREEN BELT

There are five purposes of including land in Green The National Planning Policy Framework contains Belts: the current planning guidance for local authorities. It replaced secondary objectives in PPG2 with a single to check the unrestricted sprawl of large built- clause: up areas; to prevent neighbouring towns from merging Local planning authorities should plan positively to enhance the beneficial use of the Green Belt, into one another; such as looking for opportunities to provide access; to assist in safeguarding the countryside from to provide opportunities for outdoor sport and encroachment; recreation; to retain and enhance landscapes, visual to preserve the setting and special character of amenity and biodiversity; or to improve damaged historic towns; and and derelict land (Department for Communities to assist in urban regeneration, by encouraging and Local Government, 2012, p. 19) the recycling of derelict and other urban land.

There are exceptions that allow development in the Green Belt, and are discussed: Once Green Belts have been defined, the use of land in them has a positive role to play in fulfilling When considering any planning application, local the following objectives: planning authorities should ensure that substantial weight is given to any harm to the Green Belt. to provide opportunities for access to the open ‘Very special circumstances’ will not exist unless countryside for the urban population the potential harm to the Green Belt by reason of to provide opportunities for outdoor sport and inappropriateness, and any other harm, is clearly outdoor recreation near urban areas outweighed by other considerations. to retain attractive landscapes, and enhance landscapes, near to where people live Extensions are permitted and brownfield land is to improve damaged and derelict land around re-developable and limited infilling in villages, and limited affordable housing for local community towns needs under policies set out in the Local Plan. to secure nature conservation interest (Department for Communities and Local to retain land in agricultural, forestry and Government, 2012, pp. 20–21) related uses (Department for Communities and Local Government, 2001)

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MASTERS DESIGN REPORT

FROM GREEN BELT TO BLUE SIEVE

3.2 The Metropolitan Green Belt Today The Metropolitan Green Belt (MGB) covers 5,160 square kilometres in 68 local authorities over eight counties. It envelopes Greater London, and incorporates towns scattered throughout the Green Belt. The M25 motorway, major radial motorways, and 78 rail stations are also within the MGB as shown in Figure 13.

Greater London Metropolitan Green Belt Motorways Urban Areas Rail Rail Stations Counties

0 km

15

30

30

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RETHINKING LONDON’S METROPOLITAN GREEN BELT

Figure 13: Metropolitan Green Belt with motorways, rail and urban areas

0

31

5

10

20 km

(Lau, 2017)

MASTERS DESIGN REPORT

FROM GREEN BELT TO BLUE SIEVE

++

+

National cultural and historic features are protected by designations such as ‘Sites of Scientific Interest (SSI)’ and ‘Areas of Outstanding Natural Beauty (AONB)’, some of which overlap with the Green Belt (Figure 14). The environmental condition of the MGB varies, ranging from pristine, natural habitats, to commercial and industrial sites with derelict buildings.

Metropolitan Green Belt Metropolitan Green Belt Thames River Basin District Thames River Basin District Historic Parks & Gardens Historic Parks and Gardens Battlefields Battlefields Sites Scientific Interest(SSSI) Sites ofof Scientific Interest Areas of Outstanding Natural Areas of Outstanding Natural Beauty Beauty (AONB)

0 km

15

30

32

RETHINKING LONDON’S METROPOLITAN GREEN BELT

+

+

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Figure 14: Areas of Historic and Cultural Value in the Metropolitan Green Belt (Lau, 2017) 33

0 km

10

20

40

MASTERS DESIGN REPORT

FROM GREEN BELT TO BLUE SIEVE

Despite only having 13.22% of land classified as agricultural grades 1 or 2 (considered best and most versatile by Natural England), more than half of the MGB is used for farm related activities7. Only 22% of land is publicly accessible through environmental designations and 7.1% of London’s Green Belt is covered in golf courses (Quod et al., 2015). In the 1980’s, agricultural policy sought to achieve a wider range of benefits including conservation, recreation and food production.

The Environmental Stewardship scheme was funded by the European Union and provided varying subsidies for farmers, depending on their level of stewardship. These agreements expired in 2015 (Quod et al., 2015).

7 This includes ‘arable’, ‘horticultural’ or ‘improved’ land.

Improved grasslands are ‘managed’ or ‘mown’ and therefore can be considered an agricultural use (Morton et al., 2011).

Agricultural Rating

Area (km2)

% of total

Grade 1

88.88

1.73

Grade 2

589.16

11.48

Grade 3

2929.7

57.11

Grade 4

455.16

8.87

Grade 5

1.69

0.03

806.81

15.73

258.52

5.04

Non-agricultural Urban MBG total

5129.9

Table 2: Agricultural Grades in the MGB

Grade1 1 Grade Grade22 Grade Grade33 Grade Grade44 Grade Grade Grade55 Metropolitan (MGB) MetropolitanGreen Green Belt Belt (MGB) Thames ThamesRiver RiverBasin Basin District District Environmental Stewardship Schemes (Organic and High Level) 0

5

10

0 km

20 mi

15

30

34

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1.67 17.02

36.29

6.58 0.31 1.27 0.11 0.89 3.06 32.08

RETHINKING LONDON’S METROPOLITAN GREEN BELT

AGRICULTURAL Built Up Areas + Gardens Coastal

Freshwater Salt Water Mountain Heath Bog

Semi-Natural Grassland Improved Grassland Arable

Coniferous Woodland Broadleaf Woodland

Figure 15: Land cover in the MGB (Lau, 2017; Data: Centre for Ecology & Hydrology)

Figure 16: Agricultural Classification Map (Lau, 2017) 35

FROM GREEN BELT TO BLUE SIEVE

MASTERS DESIGN REPORT

Development in the near future

The Green Belt has stood the test of time and for over six decades, it has been a compromise that brought many, Planning applications, for mostly residential often opposing stakeholders together to create it. developments, are being approved by local authorities To central government it assists in the essential in an uncoordinated fashion, and in a number of tasks of interest mediations and compromise which Metropolitan Green Belt locations. A 2016 study planning policy-making represents…. To local found a range of what are considered to be ‘threats’ government it delivers a desirable mix of policy to the Green Belt (London Green Belt Council & control with discretion. To local residents of the Campaign to Protect Rural England, 2016). These outer city it remains their best form of protection include institutional, commercial, renewable energy and against rapid change. To the inner city local residential developments as well the proposed removal authority, it offers at least the promise of retaining of Green Belt areas by local councils. Of the ‘threats’ some economic activities that would otherwise leave shown in Figure 17, the proposed residential units the area; and to the inner city resident it offers the prospect, as well as often the reality, of countryside equate to 123,528 dwellings. Their study argues that recreation and relaxation. To the agriculturalist housing targets, and mandatory requirements to specify it offers a basic form of accessible, cheap, and sites for development are the primary cause of threats to exploitable natural resources. Industrial developers the Metropolitan Green belt. and house-builders complain bitterly about the rate at which land is fed into the development pipeline, 3.3 The Benefits and Disbenefits yet at the same time are dependent on planning to provide a degree of certainty and support for Whether Green Belt policy should change or remain, profitable investment (Martin J. Elson, 1986, p. is a highly contentious debate but would not be so if it 265). weren’t for the multitude of benefits and disbenefits it has provided over time. Decades ago, London’s Green The Metropolitan Green Belt is most criticized for locking Belt was shown to prevent ‘leapfrogging’, which was up the land supply at a time when the city is enduring a becoming evident in American cities (Hall, 1974). A housing crisis. Interestingly, planners of the 1950’s were study commissioned by the British government found acutely aware of the impact Green Belts would have on that Green Belts were successful in achieving what they the supply and cost of housing. The Chief planner at the set out to do, which at the time included preventing time warned Minister Sandys not to adopt the policy for sprawl, preventing towns from merging into one another, this reason. Related to affordability, is the issue of rising and protecting the countryside from development. Post inequality, and disproportionate benefits provided to the war containment policies like the Green Belt encouraged rich by ‘helping to turn housing into investments assets sustainable development patterns, resulting in a range instead of places to live’ (Cheshire, 2014, p. 17). Hall’s of additional benefits including infrastructure efficiency attack on containment policies in post-war planning in and reduced vehicle congestion and emissions (M. J. England is even stronger: Elson, Walker, Edge, & Macdonald, 1993).

They have had clear effects on distribution of A 2010 study examined the uses that the Green Belt costs and benefits among different sections of the provides, finding that it contributes towards ecosystem community. Most rural dwellers - certainly those services, food production and recreation, but ‘could who view the countryside as a way of life rather than as a place of work - have gained; by establishing a have even a greater significance in the future if it is civilized British version of apartheid, planning has managed effectively to maximise the benefits that a preserved their status quo. This group has probably natural environment can deliver’ (Natural England & gained more and lost less than any other; and it has Campaign to Protect Rural England, 2010, p. 7). The been quick to seize on the opportunities of public National Ecosystem Assessment argues that agricultural participation in planning (Hall, 1974, p. 406). land, in addition to providing food, provides cultural services like aesthetics (UNEP-WCMC, 2011).

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RETHINKING LONDON’S METROPOLITAN GREEN BELT

Threat Type Residential Development Residential (Number unknown) Removal of Green Belt

Threat Type Planning Application Type Residential Development Residential Development Residential (Number Residential (No. unknown) unknown) Removal of Green Belt Belt Removal of Green Institutional/Commercial/Energy Institutional/Comm/Energy

Institutional/Commercial/Energy

Residential Number ofNo. Residential Units 0 - 2500 2501 - 5000 2501 - 5000 5001 - 7500 5001 - 7500 7501 - 10000 7501 - 10,000 0 - 2500

Units

0 km

10

20

Number of Residential Units 0 - 2500 2501 - 5000 5001 - 7500 7501 - 10000

Figure 17: Approved Development proposals in the Metropolitan Green Belt (Lau, 2017)

37

FROM GREEN BELT TO BLUE SIEVE

If containment policies no longer do what they set out to do – contain jobs and housing - should they not be reexamined?

The European union defines ‘functional urban areas (FUA)’ as Metropolitan areas designated by their labour basins (2014). Figure 19 compares London’s FUA with its administrative boundary, illustrating that the region functions quite differently to how it is governed.

Conflicts in national and municipal policy result in uncoordinated development occurring on land that is meant to be permanently protected. Local planning authorities are required by the NPPF to identify sites for future residential development (plus an additional 5%) in their local plans, based on ‘objectively assessed need’ (Department for Communities and Local Government, 2012, p. 12). The NPPF also sets out guidance for the protection of Green Belts. Following the release of the amended London Plan in 2016, 51 district councils, planning authorities and chief planners objected to the plan.

MASTERS DESIGN REPORT

In the context of regional growth, it is clear that there is little coordination or discernment guiding development at the local and regional scale.

Ironically, the MGB is both praised and criticised for its recreational, environmental and agricultural value.

Critics argue that despite 22-30% of the MGB being publicly accessible, it is not necessarily accessible by rail and when it is, it can take over 90 minutes to get to it from Central London (Mace et al., 2016). Affordable access to recreation in the MGB is therefore limited to those who live nearby or who own a car. Our understanding of the actual environmental quality, and resulting benefits within the MGB is also quite vague, as described in an attempt to debunk the assumption that Green Belts have little environmental value: The Green Belt’s primary purpose is to prevent urban sprawl, but in doing so it provides countryside close to 30 million people. A huge proportion of it has considerable environmental value. In the face of climate change, it has an increasingly important role in storing carbon and preventing flooding and is a vital economic resource for food security and soil protection (Campaign to Protect Rural England, 2015, p. 3).

Some districts point out that they are under pressure to develop sites within the Green Belt, while the London Plan retains an absolute protection of Green Belt land within the London boundary, and that the Mayor and London boroughs should also assess the potential for sites within the Green Belt to provide new homes.

A policy review showed that the environmental functioning of Green Belts has either been secondary or completely excluded from policy, which may be one reason why it has not been evaluated in much detail. That said, a simple analysis of land cover data shows that more than 60% of the MGB is related to an agricultural use and UNEP determined that intensive agriculture yields The Home Counties districts have made it clear that negative environmental benefits (2011). Additionally, they have no intention of planning to provide for this deficit and in fact insist that they are struggling farming in the Green Belt is often seen as a to plan to meet the requirements arising from their particularly marginal economic activity as it can be indigenous population growth (Bowie, 2016, p. 67). more likely to face a range of additional problems including damage due to trespass, vandalism and fly tipping, which give rise to additional operating costs (Natural England & Campaign to Protect Rural England, 2010, p. 66).

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RETHINKING LONDON’S METROPOLITAN GREEN BELT

Buckinghamshire Hertfordshire

Essex

Bedfordshire

Berkshire

Surrey Kent

0

5

10

20 km

Greater London greater_london Functional London

0 km

15

30

Urban Area

Local Districts + Counties district_borough_unitary_region Metropolitan Green Belt

Figure 18: A Comparison between Administrative and Functional Urban Areas (Lau, 2017)

39

FROM GREEN BELT TO BLUE SIEVE

MASTERS DESIGN REPORT

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RETHINKING LONDON’S METROPOLITAN GREEN BELT

PART II

The Development of the Blue Sieve

41

FROM GREEN BELT TO BLUE SIEVE

MASTERS DESIGN REPORT

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0 4.

RETHINKING LONDON’S METROPOLITAN GREEN BELT

F R O M STO P P I N G TO P LANNING FO R GROWTH

4.1 Terms and Concepts Ecosystem Approach and Services

The ‘ecosystem approach’ was introduced at the Rio Earth Summit in 1992 and builds on the concept of ‘sustainable development’8, but is more specific in articulating the relationship between the impacts of urban development with people and the environment.

An ecosystem approach is a strategy for the integrated management of land, water and living resources that promotes conservation and sustainable use in an equitable way. Thus, the application of the ecosystem approach will help to reach a balance of the three objectives of the Convention: conservation; sustainable use; and the fair and equitable sharing of the benefits arising out of the utilization of genetic resources (UNEP, 1992).

8 Sustainable Development’ was first defined in the Brundtland Report (1987) as ‘development that meets the needs of the present without compromising the ability of future generations to meet their own needs’ (Brundtland & Khalid, 1987).

43

The Millennium Ecosystem Assessment’s (MEA) definition of ecosystem services is aligned with, and builds upon the ecosystem approach. They are defined as ‘the benefits people obtain from ecosystems. These include provisioning, regulating, and cultural services that directly affect people and supporting services needed to maintain the other services’ (MEA, 2003, p. 49). ‘Benefits’ refer to a broad range of well-being outcomes including physical and mental health, material security, personal freedoms, and good social relations. Figure 19 highlights water-related ecosystem services, which will be the area of focus for this study – and illustrates the relationships between these ecosystem services, constituents of well-being, and direct and indirect drivers of change.

MASTERS DESIGN REPORT

FROM GREEN BELT TO BLUE SIEVE

CLIMATE REGULATION FLOOD REGULATION

WATER PURIFICATION

DISEASE REGULATION

WELL-BEING

REGULATING CULTURAL

FREEDOM OF CHOICE

PROVISIONING

SUPPORTING

ECOSYSTEM SERVICES HEALTH BASIC MATERIALS SECURITY GOOD SOCIAL RELATIONS

DIRECT DRIVERS OF CHANGE CLIMATE CHANGE

INDIRECT DRIVERS OF CHANGE

CHANGES IN LAND USE

DEMOGRAPHIC

EXTERNAL INPUTS

ECONOMIC

SPECIES INTRODUCTION/REMOVAL

SOCIOPOLITICAL

NATURAL / PHYSICAL/BIOLOGICAL

SCIENCE + TECHNOLOGY

HARVEST + RESOURCE CONSUMPTION

CULTURAL + RELIGIOUS

TECHNOLOGY ADAPTATION / USE

(MEA, 2005)

Figure 19: Ecosystem Services (Lau, 2017) 44

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first, before growth. With a green infrastructure map, communities work together to evaluate and prioritize which areas to protect. Equipped with this information, communities can create a development plan that takes into account how to preserve and connect valuable landscapes— inside and outside boundaries—while growing in a sustainable way.

New developments and citizens benefit from landscapes that preserve Green Infrastructure a community's identity, support environmental The term green infrastructure has been around since values and biodiversity, the mid 90’s and although there is no singular definition and avoid hazard areas.

1. Cores – These are areas of high conservation value and ecological quality that form the heart of the ecological network. They may contain rare or important habitats or have the conditions to support them.

RETHINKING LONDON’S METROPOLITAN GREEN BELT 2. Corridors –These are connectors that improve the functional and ecological connectivity between core areas, enabling species to move between them. Corridors may also act as links between communities and nature.

it ‘typically refers to an interconnected network of multifunctional green-spaces that are strategically planned and managed to provide a range of ecological, social, and economic benefits’ (Matthews et al., 2015, p. 156). Other sources emphasize the importance of the configuration and connectivity of green infrastructure.

There is strong evidence that connected networks are critical to sustain the capacity of our natural environment to provide ecosystem services such as A Green Infrastructure for the U.S. clean water, climate regulation, and crop pollination as well as providing habitats for wildlife (Munoz-Criado, 2016).

A connected network of cores and corridors, which form the ‘building blocks’ of a green infrastructure network are illustrated in figure 20. A core is ‘an area or patch of relatively intact habitat that is sufficiently large to support more than one individual of a species’; an edge is ‘the transitional boundary of a core, where the vegetation assemblage and structure differs markedly from the interior’ and corridors are ‘linear arrangement of a habitat type or natural cover that provides a connection between cores and differs from adjacent land (Firehock & Walker, 2015, p. 12). Roads, rail and urban development are all considered obstructions, that fragment connected landscapes.

The definition of green infrastructure has evolved and is specifically considered to be ‘a resilient approach to managing wet weather impacts that provides many community benefits’ (US EPA, 2015). The relationship between water resource management and green infrastructure is inextricable.

45

Figure 20: Core, edge and corridor (Munoz-Criado, 2016)

Water is ‘essential for establishing and maintaining green infrastructure’ and, at the same time ‘using green infrastructure for urban water management may offer innovative, cost- effective, socially preferable and environmentally sustainable solutions’ (Everett, Lamond & Lawson, 2015, p.50).

The integration of urban water management and green infrastructure is growing, with similar principles being adopted globally. Equivalent models include low impact development (LID) in the United States; Water Sensitive Urban Design (WSUD) in Australia; Sustainable Urban Drainage Systems (SUDS) in the United Kingdom, and Green and Blue Space Adaptation for Urban Areas and Eco Towns (GRaBS) in the EU (Everett et al., 2015; Fletcher et al., 2015).

FROM GREEN BELT TO BLUE SIEVE

Tzoulas et Al (2007) have found a direct relationship between green infrastructure and ecosystem health by integrating the disciplines of landscape, planning and public health. They derived a conceptual framework based on an interdisciplinary literature review and posit that ‘ecological functions and ecosystem services derived from a green infrastructure contribute to ecosystem health and to public health, respectively’ (Tzoulas, 2007, p. 170).

Current perspectives on the equity of green infrastructure projects are varied. Some (Dunn, 2010; Rouse & Bunster-Ossa, 2013) suggest that green infrastructure has the potential to address issues of equity by improving environmental conditions, health and quality of life, local food production, recreation and community building for all communities. The ‘triple bottom line’ refers to the multiple benefits provided by green infrastructure to the environment, the economy and local communities. Environmental benefits range from stormwater reduction and purification, the mitigation of urban heat island effect, ecosystem rehabilitation and climate change adaptation. Economic benefits are both direct and indirect and might include reduced health costs, employment opportunities, tourism, reduced energy and infrastructure costs and increased property value. Wolch et al. (2014) have been critical of green infrastructure projects for their failure to address environmental justice issues, such as The potential to exacerbate gentrification in low income communities.

Since urban green space increases neighbourhood desirability, property values and taxes increase too, ultimately pricing out low income households. Wendel et al. (2011) find that it is the distribution, accessibility and quality of green space and water features that result in environmental, and therefore health injustices among low income communities. Ultimately, they support green and water infrastructure projects and recommend stakeholder engagement, and the provision of amenities within these projects.

MASTERS DESIGN REPORT

Water Sensitive Urban Design

Water Sensitive Urban Design (WSUD) is a framework that supports the Australian government’s Water Sensitive Cities policy initiative. The Australian government defines WSUD as

‘the integration of urban planning with the management, protection and conservation of the urban water cycle that ensures that urban water management is sensitive to natural hydrological and ecological processes’ (T. Wong & Brown, 2011, p. 485).

It is regarded as the ‘most extensive and enveloping conceptual structure with regard to urban water management’ (Everett et al., 2015, p. 54).

The WSUD approach mimics the natural hydrological cycle by integrating three streams of water – potable water, waste water and storm water – in order to achieve its principal objectives including water conservation, waste water minimization and stormwater management. The natural hydrological cycle, which includes processes such as transpiration, runoff and infiltration regulates aquatic ecosystems by ensuring for example, water purification, soil moisture and stream flow. Urban development disrupts many of these processes and contributes towards stream erosion, the increase of pollutants entering urban water bodies and surface flooding. WSUD aims to minimize the impacts to the natural water balance, typically caused by urban development (Figure 21).

The six pillars of Ecologically Sustainable Development are land use, transport, energy, population, solid waste and Water Sensitive Urban Design (Figure 22). WSUD therefore, is not intended to be a standalone approach to development, but rather, one aspect that specifically focusses on the ‘interactions between the urban built form and the urban water cycle’ (T. Wong & Brown, 2011, p. 486), that ultimately become integrated into a comprehensive planning approach.

46

of land development t

using stormwater in the landscape to maximise visual and recreational amenity and RETHINKING LONDON’S METROPOLITAN GREEN BELT promote an understanding of water in the urban environment.

TATUM LAU

e r

Natural Water Balance

Urban Water Balance Precipitation

Precipitation Evapo-transpiration

Imported Potable Water Reduced Evapo-transpiration

W R

es

Runoff

Large Volumes of Poor Quality Runoff

Wastewater Discharge Reduced Infiltration

W D

Infiltration

alance

WSUD Water Balance

NATURAL WATER BALANCE

URBAN WATER BALANCE

Figure 5 — The Urban Water Cycle showing changes to the natural water cycle with Precipitation traditional urban development and with WSUD (Hoban and Wong, 2006)

n

Natural State

Evapo-transpiration Reduced Evapo-transpiration

Wastewater Reuse Stormwater Reuse

Runoff

Large Volumes of Poor Quality Runoff

Stormwater Treatment Wastewater Discharge

Infiltration

WATER SENSITIVE URBAN DESIGN WATER BALANCE Figure 21: Water Balance Natural State 47

Altered State

(Hoban and Wong, 2006)

Altered State

n Design (WSUD)

MASTERS DESIGN REPORT

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rban Design (WSUD)

oach

o ter to proach

Ecologically Sustainable Development Ecologically Sustainable Development

d and water WSUD nt and y of water

aking process.

Energy Land Use Transport Energy Land Use Transport

Water Sensitive Urban Design Water Sensitive Urban Design

Population

Population

Solid Waste

Solid Waste

urces ve to conserve

Urban andand BuiltBuilt FormForm UrbanDesign Design

Potable

es

Waste

Potable Waste Water Water Economic, Water Water Economic, Environmental and Social Environmental and Benefits Social Benefits

ble Development ban planning and

nt and

Stormwater

Stormwater

Urban planning Urban planning Architecture Architecture Pedestrian movement Pedestrian&movement Traffic management road design Recreation open space management Traffic &management & road design Human comfort & microclimates Recreation & open space management Sense of place & identity Human comfort & microclimates Response to climate and topography Sense of place & identity Response to socio-economic factors

Response to climate and topography Response to socio-economic factors

Figure 3 — Role of WSUD in achieving Ecologically Sustainable Development (Hoban and Wong, 2006)

Figure 3 — Role of WSUD in achieving Ecologically Sustainable Development (Hoban and Wong, 2006)

Figure 22: WSUD within Ecologically Sustainable Development Framework (SEQ HWP, 2009)

Sensitive Urban Design

e Urban Design

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4.2 Methods Each method is described in this section. Table 3 provides a summary of questions, methods and objectives that will be used in the analysis.

The Natural Assets Method

The Natural Assets Method was developed by the Green Infrastructure Center, a non-profit organization that helps government agencies and communities make informed decisions about land management and development. Identifying a green infrastructure network of intact natural landscapes, forms the basis of the land planning study using the natural assets method.

Intact natural landscapes help protect water resources. Depending upon internal land cover, cores can alter pollutants, allow for groundwater recharge, cool streams and provide habitat and food for a variety of species. Surface waters within cores add value by providing habitat for aquatic and semi-aquatic species, as well as water sources for terrestrial creatures (Firehock & Walker, 2015, p. 123).

Question

Methods

Objectives

To what extent does the MGB provide ecosystem services?

The Natural Assets Method

To identify green infrastructure that supports water-related ecosystem services (infiltration, purification, storage, flood control)

How can decisions to identify suitable development sites in the MGB be made?

Spatial Analysis in Geographic Information Systems (GIS)

To identify development constraints and opportunities in the MGB

How do water sensitive development practices and methods mitigate their impact on ecosystem services?

Pilot Study using Water Sensitive Urban Design Conceptual Process

To simulate the development process using local data in the UK context.

Table 3: Research Methods

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Map Green Infrastructure Network

Groups Potential Cores

Layers National Land Cover data National Parks Local Nature Reserves Country Parks Ancient Woodland

Fragmenting Features

Urban Land Cover Suburban Land Cover Arable Land Cover Improved Grassland class Motorways (100m buffer) Class A & B Roads (100m buffer) Railways (50m buffer)

Water Network

General

Catchment Basins

Riparian Corridors

Stream Network (100m buffer) Flood Zones Surface Water Bodies Fault Lines Catchment Basins Stream Network (100m buffer)

Recharge Zones

Aquifers Fault Lines

Table 4: Natural Assets Method Data Process

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1

SET COMMUNITY GOALS

LOCATE NATURAL LAND COVER

2

REVIEW DATA AND PROXIES

ADD FRAGMENTING FEATURES

3

MAP ECOLOGICAL & CULTURAL ASSETS

4 5 6

ASSESS RISKS

BASE (GI) MAP

ECOLOGICAL ASSETS CULTURAL ASSETS

IDENTIFY OPPORTUNITIES

CLIP FRAGMENTING FEATURES

SUBTRACT EDGE HABITAT

RANK CORES BY SIZE & SHAPE

IMPLEMENTATION Figure 23: Natural Assets Method (Adapted from Firehock & Walker, 2015)

Environmental Systems Research Institutes (ESRI) new Green Infrastructure tool9, which was developed using this method, combines and processes most of the data necessary for green infrastructure planning, and makes it freely available to communities. ESRI’s tool is currently limited to the U.S., therefore in this study, equivalent U.K. data has been used to conduct a similar analysis in ArcGIS. Table 4 shows the data used to produce the maps.

Figure 23 shows the full extent of the natural assets method, which includes participatory planning, technical analysis and implementation. The steps that have been incorporated into this study (highlighted in green) are limited to the technical analysis, which uses GIS to identify green infrastructure networks.

9 http://www.esri.com/about-esri/greeninfrastructure 51

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Spatial Analysis using Geographic Information

Hydrologic and Slope Analysis in Geographic

Systems

Information Systems

Publicly accessible data are used to identify development Stage C in the WSUD conceptual design process calls opportunities and constraints using spatial analysis for a detailed site analysis. The overall site analysis methods. Spatial analysis is referred to as, requires a study of the behaviour of stormwater runoff (hydrological analysis) and an understanding the the process of examining the locations, attributes, site topography (slope analysis). ESRI ArcGIS’ spatial and relationships of features in spatial data through analysis extension toolbox includes hydrological and overlay, and other analytical techniques in order to address a question, or gain useful knowledge. Spatial slope tools. A digital elevation model (DEM) raster will analysis extracts, or creates new information from be used as the primary input to determine the steepness of slopes and direction of water flow. Each of these, will spatial data (ESRI, n.d.). inform the infrastructure design and layout.

What are considered to be regional opportunities or constraints are dependent on context, and should Table 6 summarizes the process and objectives for each be determined by stakeholders through democratic, tool. participatory dialogues, ahead of time. In the context of this study, constraints are natural assets that provide Storage Assessment using Qmed estimation water-related ecosystem services, including flood Quantitative modelling is the last step in the WSUD regulation and water purification. Versatile soils, that conceptual design process (Table 5). Stormwater storage support local food production will also be considered assessments are one of several assessments that would as a constraint to demonstrate how local planners need to be carried out in a WSUD development. A might consider a range of factors simultaneously. The stormwater storage assessment calculates runoff, and the proximity to a rail station within the MGB, will be resulting storage requirements for stormwater treatment, considered an opportunity, since it takes advantage of capture and reuse. Providing infrastructure to capture existing transportation infrastructure. This analysis will and reuse stormwater reduces flood risk, increases water also determine potential development opportunities, of quality in nearby streams and diversifies local water which one will be selected for a pilot study. supplies.

WSUD Design Process

The WSUD development and design process is based on guidance from South East Queensland’s Healthy Waterways Partnership document ‘Water By Design: Concept Design Guidelines for Water Sensitive Urban Design (2009) and will be tested on a pilot site. Typically, the WSUD design process includes a multidisciplinary team working at multiple scales. The processes are described in Table 5, with steps specific to town planners or urban designers indicated. Tasks 5, 7, 8, 9, 15 and 16 are not typically carried out by a planning or urban design team, but are completed at a high level in order for necessary assumptions to be incorporated into the pilot study.

A U.K. based civil engineering and environmental hydraulics consultancy firm, designed an online tool to carry out a storage assessments10, using standards set by the Environmental Agency. The calculator uses location-based and development specific data, and the Qmed estimation statistical method (HR Wallingford, n.d.). This method accounts for four types of storage as shown in Table 7. Figure 24 describes the surface water storage method incorporated into the tool.

Table 8 illustrates data inputs, incorporated factors and outputs of the calculator. Table 9 illustrates assumptions used for impervious cover percentages (impermeable area), based on land use types estimations.

10 www.uksuds.com

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Task

Team

A

Preliminary Site Analysis

01

Understand the most recent WSUD policy and regulations

02

Identify regionally and locally significant ecosystems and understand the site’s context in relation to the protection and/or enhancement of these ecosystems, particularly riparian and wetland ecosystems associated with waterway corridors

03

Identify environmental values and water quality objectives for key receiving waters within, and downstream of, the development

04

Establish ecological condition and management requirements for key receiving waters within, and downstream of, the site

05

Establish the site’s existing hydrologic cycle and its regional context

06

Understand the regional and local integrated water cycle infrastructure context

07

Understand the current and future flooding risk on, and downstream of, the site

*

08

Understand the site terrain and soils

*

09

Prepare a preliminary WSUD opportunities and constraints overlay

*

B

Establish WSUD Objectives

10

Determine water conservation objectives

11

Determine wastewater minimisation objectives

12

Determine stormwater management objectives

13

Confirm WSUD design objectives with local council

C

Conceptual Site Layout

14

Integrate the conceptual design process

P, UD

15

Undertake detailed site analysis

*

16

Undertake quantitative modelling

*

17

Prepare final conceptual site layout and present to the local council at a pre-lodgement meeting

P, UD

P

*

Table 5: WSUD Conceptual Design Process P = Planning UD = Urban Design

* = Tasks included in this study Tool

1. Data Preparation

Objective

Sink

To identify localized holes (incorrect values) in the DEM

Fill

To fill (correct) values in the DEM

2. Hydrological Analysis

Flow Direction

To determine the direction of stormwater flow from cell to cell

3. Slope Analysis

Slope

To determine the gradient of each raster surface

Table 6: Hydrologic and Slope Analysis process

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FROM GREEN BELT TO BLUE SIEVE

Storage Types

Description

Interception

aims to prevent runoff to receiving streams for small events.

This ensures the frequency of polluting the river reduces by as much as 50%. The objective of Interception storage is to prevent the first 5mm from being discharged. It is recognised that this may not always be possible for all sites.

Attenuation

aims to limit the rate of runoff into the receiving water to similar rates of discharge as that which takes place before the site is developed (greenfield runoff rate).

Long-Term

is similar to Attenuation storage, but aims to specifically address the additional volume of runoff caused by the development. This is either infiltrated into the ground or, if this is not possible due to soil conditions, attenuated and discharged at very low rates of flow to the receiving watercourse so as to minimise the risk of exacerbating river flooding.

Treatment

aims to ensure the water quality of the stormwater discharged to the river is sufficiently improved to have minimal impact on the flora and fauna in the receiving water

Table 7: Storage Type and Functions (HR Wallingford, n.d.)

Calculator Inputs / Outputs Manual inputs

Data Total Site Area (ha) Significant Open Space (ha) Net impermeable Area (ha) Hydrology of Soil Type (HOST) class

Location generated inputs (by postcode)

Rainfall depth (mm) Hydrological region Climate change allowance factor

Input Criteria

Volume Control Approach Methodology

Model Output

Greenfield Flow rate (l/s) Interception storage (m3) Attenuation storage (m3) Long term storage (m3) Treatment storage (m3)

Table 8: Storage Assessment Inputs and Outputs

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Figure 24: Surface Water Storage Method (HR Wallingford, n.d.)

55

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Land Use

Impervious Cover

Business/Commercial Downtown Areas

95

Suburban Areas

75

Residential Single-family (0.1ha parcels)

45

Multifamily

75

Industrial: Light areas

80

Heavy areas

90

Other Parks, cemeteries

10

Playgrounds

25

Schools

55

Railroad yard areas

50

Undeveloped Areas: Historic flow analysis

2

Greenbelts, agricultural

2

Streets: Paved

100

Gravel (packed)

40

Drive and walks

90

Roofs

90

Lawns, sandy/clayey soil

2

Undefined

45

Table 9: Land Use and Impervious Cover Assumptions Based on percentages from udfcd.org

56

TATUM LAU

4.3 Limitations, and implications for further research The broad scope and limited time-frame of this study allows for limited aspects of the methods to be incorporated. In the Natural Assets method, identifying green infrastructure networks using land cover data is only the first step. For this study, core size will be used as a primary indicator, however further studies should account for the core quality or richness. ESRI’s Green Infrastructure initiative uses up to 50 additional indicators including stream density, endemic species count and percentage of wetlands to rank cores. Field studies should also be carried out to confirm any assumptions made using a GIS analysis.

The GIS spatial analysis will be used to identify potential development sites in the MGB. It will consider 3 factors – proximity to rail station; agricultural soils and the MGB boundaries. As the number of factors increase, the more challenging it is to interpret the results. When including numerous factors, a weighted suitability raster analysis may be more appropriate.

Some, but not every aspect of WSUD conceptual design will be used in the study. The site analysis and layout will consider stormwater quantity as a primary factor, however additional quantitative analyses including urban water balance models, stormwater quality models and water supply and wastewater network models would have large impact on the site design. The online storage calculator does not take topography into account. To fully understand the relationships between stormwater storage and detention, a calculation should be included, at the scale of the sub-catchment, rather than development.

57

RETHINKING LONDON’S METROPOLITAN GREEN BELT

MASTERS DESIGN REPORT

FROM GREEN BELT TO BLUE SIEVE

0 5.

R E G I O N A L A N A LYS IS AND FIND INGS

5.1 Identifying Regional Constraints Geography

The selected study area extends beyond the Metropolitan Green Belt (MGB) itself, to include the eight counties in which it is located, combined with the Thames River Basin. The administrative units have governing power over the MGB, therefore, reviewing it in the context of the rest of the county is important. The Thames River Basin is the dominant basin, covering much of the western area, and central sections of the MGB. River basins and catchments are useful units of analysis, due to the fact that natural and urban hydrologic cycles occur at these scales, and as a result, urban water resources are best managed at these scales.

Potential Cores

Total Area (ha)

% of MGB

Special Conservation Areas

10,918

2.11

Special Protection Areas

8,279

1.6

National Parks

0

0

Local Nature Reserves

5,051

0.97

County Parks

7,031

1.36

Ancient Woodlands

35,634

6.87

Potential Cores identified based on national or local protection

66,913

12.91

Potential Cores identified, based on Land Cover data (<40ha)

76,109

14.83

Table 10: Area of Green Infrastructure Network

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Urban Areas Motorways Rail

Major Roads Minor Roads

Figure 25: Fragmenting Features (Lau, 2017)

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Green Assets

The purpose of a green asset analysis is to identify potential green infrastructure cores. The size, configuration, and quality of green cover, are equally important attributes that contribute towards the effective provision of ecosystem services. This analysis is limited to size and configuration, therefore the term ‘potential’ is used, with a disclaimer that field studies would need to be carried out to verify the health and quality of the green infrastructure.

A green infrastructure base map was created by, first identifying parcels characterized as having a dominant land cover class that may provide water-related ecosystem services. Broadleaf woodland, coniferous woodland, semi-natural grassland, mountain, heath, bog, saltwater, freshwater, and coastal classes from the Land Cover dataset (Centre for Ecology and Hydrology, 2007) have been combined. Fragmenting features (Figure 25) are then subtracted from the combined land cover classes, to identify remaining contiguous cover.

‘Impact zones’ or ‘edge habitats’ are subtracted from the remaining cover, based on the magnitude of their impact (100m for Motorways, Road classes A and B; 50m from railway lines11). This process resulted in the identification of potential green infrastructure cores.

Potential green infrastructure cores under 40 hectares were removed and the remaining cores were ranked by their size (greater than 40 ha; greater than 1000 ha).

At this scale, ranking the cores by shape (as per the methodology) was not possible, but this step is covered later, at the catchment scale.

11 Minor roads were not considered as fragmenting features.

Area - 1000.000000 Area 40.011625 Metropolitan Green BeltBelt Metropolitan Green 40.011625 - 1000.000000 1000.000001 9143.108500 Thames River Basin District Thames River Basin District Green Infrastructure Cores (<100ha) 1000.000001 9143.108500 special_conservation_areas_clip Green Infrastructure Cores (<40 ha) Green Infrastructure Cores (<1000ha) special_conservation_areas_clip special_protection_areas_clip Special Conservation / Special Protection Areas Special conservation areas / Special protection areas special_protection_areas_clip National Parks / Local Nature Reserves / Country national_parks_clip Parks / Ancient Woodlands national_parks_clip local_nature_reserves_clip National Parks / Local Nature Reserves / Country Parks / Ancient Woodland local_nature_reserves_clip countryparks_clip countryparks_clip ancient_woodland_clip

0 km ancient_woodland_clip

15

30

0

12.5

25

50 km

0

12.5

25

50 km

60

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Figure 26 illustrates the identified potential green infrastructure cores, as well as other protected or designated open spaces (parks, ancient woodlands, national reserves), which are considered as potential green infrastructure.

There are very few large (over 1000 hectares) cores, although this is not surprising when one considers the share of agricultural land and road infrastructure throughout the green belt. Cores identified using the Natural Assets method often overlap with areas already designated for protection. Table 10 summarizes potential green infrastructure cores and illustrates that approximately 10,000 hectares of the MGB could potentially provide further ecosystem services, but are currently not protected under other designations.

Figure 26: Potential Green Infrastructure Cores (Lau, 2017) 61

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Blue Assets

Blue assets are characterized as features in the study area, that either have the potential to provide waterrelated ecosystem services, or protect regional water resources. They include groundwater recharge zones, flood zones and riparian buffers and corridors.

Figure 27 shows the location of ‘moderately or highly productive’ (those that are permeable and provide water storage) aquifers, which make up 52.6% the MGB. Of those, 42.52% are considered ‘highly productive’ and the remaining 10.06% ‘moderately productive’. Above ground recharge areas are thought to be where fault lines and aquifers overlap, indicated by the thick brown line. Surface water bodies include streams and lakes. A 100m buffer has been applied to these water bodies to identify riparian corridors.

Metropolitan Green Belt Thames River Basin District Streams Fault Lines Flood Zone Highly Productive Aquifer Moderately Productive Aquifer

0

12.5

25

0 km

50 km

15

30

62

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Figure 27: Water Network (Lau, 2017) 63

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Water Sensitive Areas

The term ‘water sensitive areas (WSA)’ is adopted to describe the parts of the study area that have the potential to provide water-related ecosystem services, such as water purification, water storage and flood mitigation. This does not mean that these areas are limited to water-related ecosystem services12, however these are drawn out to identify ecological constraints in the context of urban water management. Table 11 illustrates that approximately 35% of the MGB has water sensitive areas. Figure 28 illustrates the water sensitive areas - the combination of green and blue assets, as previously identified in this section – overlaid with future development proposals (CPRE, 2016). This analysis shows that 153 developments will occur in ‘water sensitive areas’, should they go ahead.

12 The literature review emphasizes the inter-related, multiple ecosystem services provided by green infrastructure.

Factors

Area (ha)

% of total

Water Sensitive

181,731

35.34

Non-Water Sensitive

332,577

64.66

MBG total

512,990

100

Table 11: Water Sensitive Areas

Metropolitan Green Belt Thames River Basin District Development Threats Recharge Zones Lakes Riparian Buffers GI Cores Flood Zone 50 km

0 km

15

30

64

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Figure 28: Water Sensitive Areas and ‘Threats’ (Lau, 2017) 65

0

12.5

25

50 km

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1

5.2 Identifying Regional Opportunities Rail Station Selection

In order to narrow down the process of identifying regional development opportunities, the proximity to an existing rail station was considered, since it already provides transportation infrastructure for future development. For the purpose of this study, the 78 stations in the MGB were considered, however rail capacity and train frequency were not. A spatial analysis was used to exclude any rail station that is located in water sensitive areas, or on soils with an agricultural grade of 1 or 2.

Out of the 78 rail stations in the MGB, 72 do not fall within areas with versatile agricultural soils. The 72 stations were further assessed by their proximity to water sensitive areas. ‘Proximity’ was assessed on the basis of 3 distance thresholds – 0m, 100m and 200m. Table 12 shows the number of identified stations by proximity.

The seven stations that were not in 100m of WSAs or versatile soils were then selected for further evaluation.

The stations are shown in Table 13 and Figure 29.

4

5 Potential Development Stations Future Rail Stations Future Rail Route Existing Rail Stations Rail Water Sensitive Areas Areas of Low Agricultural Value Urban Areas Counties

0 km

10

3

2

25

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Proximity

Stations not in Grd 1 or 2 soils or WSAs

0m

60 out of 72

100m

26 out of 72

200m

7 out of 72

Table 12: Station proximity to WSAs or versatile soils Map ID

6

7

Stations

Local Authority

1

Aspley Guise

Central Bedfordshire

2

Shalford

Guildford

3

Clandon

Guildford

4

Upper Halliford

Spelthorne

5

Ewell East

Epsom Ewell

6

Chelsfield

Bromley

7

Penshurst

Sevenoaks District

Table 13: Rail Stations for further study

Figure 29: Opportunity Stations in the MGB (Lau, 2017) 67

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Selection Criteria

A preliminary land availability assessment was carried out by visually assessing the area surrounding each station (Figure 30). Three factors were considered in this evaluation: −− Percentage of Metropolitan Green Belt −− Percentage of Water Sensitive Areas −− Percentage already developed

Aspley Guise

Woburn Sands

The size of each of the two circles indicates approximately 180 hectares and 850 hectares respectively, based on preliminary assumptions about medium density, mixeduse developments of 1,500 and 10,000 units13 . Brickhill Bow Each of the seven areas requires an urgent and detailed Fenny Stratford study to determine its capability for development.

Table 14 provides additional information about each Heathrow Terminal 4 site. In the case of this study, Aspley Guise in Central Bedfordshire has been selected for the pilot, since the borough demonstrates an urgent need for additional housing.

Metropolitan Green Belt Water Sensitive Areas Urban or Suburban Land Cover Rail Whitton Motorway Feltham Twickenham 850ha / 8.5 km2

13 These assumptions are based on two case studies, shown Ashford (Surrey) in section 6.1 of this report Hildenborough

Clando

Strawberry Hill London Road (Guildford) Guildford Fulwell

Staines-upon-Thames Teddington Kempton Park Sunbury

Thames Ditton

Penshurst

Leigh (Kent)

Bromley South Malden Manor Tonbridge Worcester Park

Bickley

St Helier (Surrey) Hampton

Sutton Common Petts Wood

Effingham Junction

West Sutton Farncombe

Stoneleigh Hayes (Kent) Horsley

Wallington Thames Ditton Sutton (Surrey) Orpington Cheam Godalming

Chessington South Ewell West

Cowden

Clandon

Hersham

Ewell East

Addlestone

Hampton Court Carshalton

Shepperton

Chertsey

Swan

Hackbridge

Tolworth

Chessington North

Chilworth

Shalford St Mary Cray

Upper Halliford

ver lesdon

ldford

Ridgmont

Walton-on-ThamesBelmont

Carshalton Beeches Esher Hinchley Wood

Chelsfield

Epsom

Knockholt Banstead Epsom Downs

London Road (Guildford)

Woodmansterne

Figure 30: Development potential for selected sites

Ashtead

Tattenham Corner

Gomshall

Chipstead

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Aspley Guise

Shalford

Clandon

Upper Halliford

Ewell East

Chelsfield

Penshurst

Local District

Central Bedfordshire

Guildford

Guildford

Spelthorne

Epsom Ewell

Bromley

Sevenoaks District

Urban Area /already developed within focus area

1.687

2.670

0.881

6.099

7.012

5.270

0.120

Water Sensitive Areas within focus area

2.198

4.585

3.710

3.070

1.226

0.713

4.079

Green Belt within focus area

4.986

11.929

12.434

5.667

3.361

6.756

12.235

Ave Annual Housing Target (Borough) *

1600

828

828

151

181

641

620

Total Housing Target (Council 10/15/20 yr plan)

32000

12426

12426

3020

2715

6413

12400

Minutes to Central London **

90 - 110

65 - 80

65 - 75

66 - 75

55-60

45-55

65-75

Existing Population ***

2,195

4,142

1,363

3,173

34,872

14,507

1,628

Median House Price (by Postcode) ****

250,000

625,000

525,000

260,000

572,500

450,000

475,000

South Western Railway, Southern Railway

South Western Railway

Southern Railway

South Eastern Railway

Southern Railway

Rail Line

London Midland

Great Western Railway

* Based on Local Council Plans

*** Census 2011

** Google (Departing Weekdays at 9am

**** CDRC House prices

Table 14: Characteristics of Potential Development Areas 69

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0 6.

A WAT E R S E N S I T IVE URBAN D ES IGN D E VELO P MEN T

This chapter specifically focuses on a pilot project, whereby the Water Sensitive Urban Design conceptual design process (described in chapter 3) is applied to the selected site. A number of assumptions about the development have been made, based on local context.

These are stated in the section that follows, prior to the analysis.

−− Low density Family Housing – 20 units/ha −− Medium density Family Housing – 30 units/ha −− Medium density starter and small homes – 40 units/ ha −− Higher density Flats – 50 units/ha

6.1 Preliminary Assumptions

Central Bedfordshire have specified ‘High Performance Technologies, Research & Development (R&D) AgriFood Visitor Economy, Transport and Logistics’ as priority employment sectors (Central Bedfordshire Council, 2017, p. 159). They anticipate further growth in ‘strategic warehousing and logistics’ (Central Bedfordshire Council, 2017, p. 163), particularly in locations with good access to regional transportation links. This will guide decisions regarding land use.

Employment

The pilot project considers national and local planning policy. The National Planning Policy Framework (NPPF) requires local councils to produce long range plans, showing how, and where they will grow. Aspley Guise falls into the Central Bedfordshire council, and its local plan (Central Bedfordshire Council, 2017) is used to guide many of the decisions in this case study.

Therefore, this urban design investigation challenges current Metropolitan Green Belt policy as a means to examine more enlightened and environmentally Open Space sensitive approaches.

The local authority’s leisure strategy (Central Bedfordshire Council, n.d.) specifies the open space Housing type, mix, density requirements for new developments and is shown in The pilot study aims to address regional housing needs Table 15. and aims to accommodate residents that will work locally and regionally, based on affordable housing and access to job markets. The Central Bedfordshire plan sets out a target of 1,684 dwellings per annum, of which 30% should be affordable, as per the Strategic Housing Market Assessment (SHMA). Affordable housing includes ‘affordable rented accommodation, shared ownership, and starter homes’ (Central Bedfordshire Council, 2017, p. 137). There is need for smaller homes for first time buyers and those looking to downsize, although there is also a need for family housing. See Appendix I for more detail on local authority policies.

Climate Change and Flood Risk

The local plan confirms many of the assumptions discussed in Chapter 2, in relation to the impacts of climate change on water supply and flood risk. The council specifically states,

The design of new developments should reflect the increasing likelihood of periods of either drought or flooding, and consequently value water as a resource that can be stored in times of plenty for re-use in times Three contemporary Garden City case studies of varying of deficit. All new developments will therefore be scales have been used to inform decisions on density: expected to address the issue of water scarcity (Central Ebbsfleet Garden City (853 ha land area, 15,000 homes, Bedfordshire Council, 2017, p. 235).

30 – 90 units / ha); North West Bicester Ecotown (380 The use of green infrastructure and sustainable urban ha, 5,000 homes, 20 units/ha) and Halsnead Garden drainage systems is considered essential.

Village (174 ha, 1,600 new homes, 37 units/ha). This pilot study will use a range of the following densities:

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Types

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Accessibility

Quantity

Countryside Recreation Sites

20 minute drive time

3.19 ha per 1000 population

Urban Parks

15 minute walk (720m) 20 minute drive time

0.22 ha per 1000 pop. Major Service Centres only 0.39ha per 1000 pop. (Minor towns where/if required.

Large Formal Recreation Areas

10 minute walk (480m) for Major Settlements or, 10 minute drive time for small settlements

1.17 ha per 1000 population

Informal Recreation Areas

10 minute walk (480m)

2.5 ha per 1000 population

Small Amenity Spaces

5 minute walk (240m)

0.58 ha per 1000 population

Childrenâ&#x20AC;&#x2122;s Play Spaces

10 minute walk time (480m)

0.11ha per 1000 (it should be noted that this includes the activity

Provision for Young People

10 minute walk time (480m)

0.043ha per 1000 population (it should be noted that this includes the activity area only). Additional allowances should be made for appropriate buffer zones

Allotments

10 minute walk time (480m)

0.37 ha per 1000 population (15 plots)

Cemeteries and Churchyards

n/a

2.03 burial plots per 1000 population

Table 15: Open Space Standards for Central Bedfordshire Council (Central Bedfordshire Council, n.d.; from Table 5.1 Local Standards by Typology)

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6.2 Site Analysis Hydrologic Context

Aspley Guise station, as indicated by the red cross in Figure 31, is located in the Upper and Bedford Ouse catchment, within the Anglian River Basin. Broughton Brook, the predominant surface water body in the catchment, which flows northwards, is described as being ‘heavily modified’, with a ‘poor’ rating for ecological status (Environmental Agency, 2016). Productive aquifers in the southern half of the catchment (shown in yellow), provide opportunities for water supply and storage (Environmental Agency, 2017). The large urban area to the West of the catchment is Milton Keynes.

Management Catchments in the Anglian Water Boundary

Rail Station Land Cover Classes Urban Suburban Wetlands (Salt/Freshwater/Saltmarsh) Fault Lines Rivers Canals Lakes Highly Productive Aquifer Moderately Productive Aquifer

0 km

5

10

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Figure 31: Hydrologic Context (Lau, 2017) 73

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Strategic Context

Aspley Guise is located in a part of the region that has the potential to expand economically. The rail station is on the London Midland Rail line, which connects Liverpool, Birmingham and Coventry to London Euston. It is approximately 10km from Milton Keynes, the city that experienced the most job growth between 2003-2014, in the nation (Centre for Cities, 2015). The station is 2km from the M1 Motorway and in proximity to regional towns including potential employment centres Oxford, Cambridge, Luton and St. Albans. This area is also served by London Luton airport, only 30km away.

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Cambridge (50km)

Bedford

A 1( M

Milton Keynes Central

M1

Bletchley

)

Aspley Guise Letchworth Garden City

Oxford (65km) Hitchin

Stevenage Luton Luton Airport Parkway

Aylesbury

Rail Motorway Local Districts Aspley Guise Station Metropolitan Green Belt Urban or Suburban Land Cover

Welwyn Garden City

St. Albans (30km) London Kings Cross (50km)

Figure 32: Strategic Context (Lau, 2017)

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Existing Conditions in the Catchment

The topography of the catchment varies, and is hilly in the southern part and relatively flat in the northwestern parts. The 1:1000 year flood zone is limited to the banks of Broughton Brook. Soils include chalk, coverloam, loamy drift, glaciolacustrine clays and silts and gravel. There are small areas in the catchment that contain Grade 1 and 2 agricultural soils, versatile for food production.

Soft sandstone Weathered/fissured intrusive rock Chalk, Chalk Rubble Hard fissured Limestone Hard coherent rock Hard but deeply shattered rocks Soft Shales Very soft reddish blocky mudstones 0 km

2.5

5

Very soft massive clays Colluvium Coverloam Glaciolacustrine clays and silts Clay with flints Gravel Loamy drift

1:1000 Flood Zone Rivers Elevation (low 35m; high 260m)

Figure 34: Soils

Figure 33: Topography

(Lau, 2017)

(Lau, 2017) 76

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The dominant land cover of the parcels in the catchment are related agriculture. There is woodland and grassland cover in the south and built up areas near the station and in the north. There are small areas of ‘freshwater and inland rock’, which suggest wetlands.

Metropolitan Green Belt Major Roads Minor Roads Motorway Land Cover (Broad Habitats) Built up areas and gardens Arable and Horticulture Improved Grassland Rough low-productivity grassland Broad leaved/mixed/yew woodland Coniferous woodland Neutral Grassland Acid Grassland Dwarf Shrub Heath Freshwater Inland Rock 0 km

77

2.5

5

Figure 35: Land Cover (Lau, 2017)

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Figure 36: Green and Blue Networks

1:500 Flood Zone Fault Zones Wetlands Water Sensitive areas Highly productive aquifers Moderately productive aquifers Major Roads Minor Roads Motorway

0 km

2.5

(Lau, 2017)

Figure 36 illustrates existing blue and green networks surrounding the catchment. This includes surface water bodies and aquifers, wetlands and woodlands. Water sensitive areas (potential green infrastructure networks), as defined in chapter 5 is also overlaid.

5

The southern part of the catchment (south of the motorway and railway line) and village of Aspley Guise are all in the Metropolitan Green Belt.

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Water Sensitive Urban Design Opportunities and Constraints

Stage 9 of the WSUD conceptual design process, requires an ‘opportunities and constraints overlay’, which considers water-related, natural and humanmade features that will influence the planning and design of the development. Figure 37 illustrates the factors that have been considered. Opportunities include gentle, undulating slopes (2.5% - 15%) and proximity to aquifers (for sustainable groundwater abstraction and aquifer storage and recovery). Constraints include flood zones, water sensitive areas and grade 1 and 2 agricultural soils.

Figure 37 illustrates large portions of water sensitive areas in the upstream, southern parts of the catchment.

Since water sensitive areas are defined as potential green infrastructure cores and corridors, there is an opportunity to both restore and protect this part of the catchment. Figure 38 illustrates the proposed areas for protection, and by implication areas to be considered for development within the catchment. Using the suggested dimensions of 300m (100m corridors and 100m edges on either side) for connected green infrastructure cores and corridors, protection areas (shown in blue) are identified along streams and around WSA’s. The white outline is the resulting proposed development area, which is approximately 400 hectares.

Slope Percentage 0 - 2.49 % 2.5 - 4.99 % 5.0 - 7.49 % 7.5 - 9.99 % 10.0 - 12.49 % 12.5 - 14.99 % 15% or more 0 km

2.5

Figure 37: WSUD Opportunities and Constraints (Lau, 2017)

1:500 Flood Zone Water Sensitive areas Grade 1 + 2 Agriculture Aquifers Proposed Areas for Protection Proposed Development Area 5

Figure 38: Proposed areas for protection and development in the catchment (Lau, 2017)

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Aspley Guise Village

Area (ha)

Broad Habitat sub-class

The village of Aspley Guise, Central Bedfordshire has a population of 2,195 (2011 Census) and adjoins the town of Woburn to the west which is attractive to tourists.

The village dates back to 1086 and has a historic centre with 29 listed buildings (Aspley Guise Village Hall, n.d.). Within the identified developable area, 13% is classified as either Urban, Industrial or suburban. Table 16 summarizes the existing land cover percentages within the developable area boundary.

Developable Area (%)

Arable, Improved or rough low productivity grassland

403.78

82

Deciduous, Conifer, Mixed woodland and scrub

27.45

6

Inland Rock

0.56

0.1

Suburban

57.15

12

Urban and Industrial

4.14

1

TOTAL

493

1

Table 16: Existing Land Cover in Developable Area Source: Estimated from Land Cover 2007

M1

Mo

tor wa y

Aspley Guise Rail Station

Aspley Guise Village

Google, 2017 0 km

0.5

1

Figure 39: Aerial photo of potentially developable area boundary 80

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6.3 Stormwater Assessment based on Land Use Scenarios Chapter 2 discussed the impacts of climate change on regional water resources. In summary, the change in the seasonal distribution of rainfall, will result in water shortages during the dry season, and surface flooding during the wet season. A key challenge for a development therefore, is to design water storage infrastructure that both copes with, and takes advantage of, the seasonal changes in rainfall.

Best Manage Practices

% of Developable Area

Capture Gross Pollutant Capture

Varies 0.5

Sediment Basins Treatment Bio-retention

3

Vegetated Swales

1

The storage assessment using the Qmed estimation 10 method was outlined in Chapter 4. Since impervious Constructed Wetlands cover percentages are key data for these estimations, UV Radiation/Chlorine 0 and assumptions can be made about the percentage of impervious cover by land use, land use scenarios are an Storage effective way to understand water storage infrastructure Aquifer Storage 0 requirements, at the conceptual design stage. In adopting Detention Ponds Varies these methods, assumptions regarding the number of homes, residents and jobs can all be derived from land Table 17: Spatial Requirements for WSUD BMP’s use percentages.

(SEQ HWP, 2009) We can expect storage requirements to increase with the percentage of impervious cover.

Typically, the more urban and dense the land use, the higher the percentage of impervious cover. This results in greater rates and volumes of surface water runoff and consequently, a greater need for storm water treatment and storage. An additional consideration when land use planning for WSUD developments is ‘symbiotic land use clustering’. In principle, symbiotic land uses are those that are ‘matched on a fit-for-purpose basis to the quality of available recycled water’ (SEQ HWP, 2009, p. 46). This strategy assists in meeting WSUD objectives to minimise wastewater through recycling, thereby increasing economic efficiency by reducing the infrastructure required to deliver non-potable water.

Examples include the siting of industrial land uses, or those that require landscape irrigation, close to a centralized waste water treatment plant. Mixed use developments with residential and commercial uses are provide opportunities for WSUD solutions, since large quantities of potable water are consumed by residents can be reused by commercial tenants (e.g.. toilet flushing) (SEQ HWP, 2009).

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Scenarios and Assumptions

Three plausible land use scenarios were developed for comparison. Each are based on local policies (Central Bedfordshire Council, 2017, n.d.), with regard to affordable housing, employment and open space14, previously summarized in this chapter.

Scenario one aims to deliver as many homes and jobs as is possible, within the constraints of appropriate densities and open space requirements per capita.

Scenario two is similar to scenario one, but includes the required area for WSUD stormwater infrastructure, as shown in Table 17. Scenario three incorporates WSUD stormwater infrastructure, but is lower in density, with more than the minimum open space, as required, per capita.

Most WSUD best management practices do not require significant space within a development and can often be incorporated into public open spaces.

The exception to this are constructed wetlands, which require approximately 10% (SEQ HWP, 2009) of the development land area and are not considered as publicly accessible open space. Medium to high density residential areas were assumed to include starter or smaller homes, with an average of 2.5 residents and medium density family housing was assumed to have an average of 3 residents per household. All scenarios use a â&#x20AC;&#x2DC;Jobs per resident workerâ&#x20AC;&#x2122; target range of 0.8:1 to 1.25 based on APAâ&#x20AC;&#x2122;s recommended guidance (HousingWorks & City of Austin, 2014), which assumes that 1.5 residents per household are workers. A demographic analysis of the local authorities in proximity to each development site, ought to be carried out to inform these assumptions.

Using the stormwater storage tool described in the methods section, inputs from each scenario were entered to calculate an estimate of stormwater storage volumes.

Inputs include total site area, public open space, impermeable (or impervious) area, and soil class.

Figure 40 summarizes the breakdown of land use, impervious cover and stormwater storage percentages, dwelling units, number of residents and jobs for each scenario. Additionally, the storage volumes are interpreted as total development area percentages, at 0.5 and 1 metre depths, respectively. Appendix II includes a detailed land use and stormwater storage tables for each scenario.

A comparison between scenarios one and two shows that scenario two has 1% less homes, 3% less residents, a marginally higher number of jobs per resident worker and requires 23% more stormwater storage. This finding shows how an additional 10% of impervious cover, attributed to the constructed wetlands, impacts stormwater storage requirements. Although 23% may sound high, when interpreted in as a percentage of the total development area, Figure 40 illustrates a difference of 1% or 2%, depending on storage infrastructure depth.

A comparison between scenarios two and three shows that scenario 3 has 21% less homes, 20% less residents, 113% more jobs per resident worker and requires 3% less stormwater storage. When compared as a percentage of the total development area, there is less than a 0.2% or 0.4% difference, depending on the storage infrastructure depth. From an infrastructure cost-sharing perspective, scenario two is no doubt the most efficient. Surface water storage options and the implications are explored in the section that follows.

14 Based on South East Queensland Policy where Water Sensitive Urban Design standards are in place. Central Bedfordshire does not specifically outline the types of stormwater infrastructure that constitutes as open space.

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Scenario One Medium Density New Town

Land Use: Land Use: residential residential employment Land Use Use: Land employment open space Residential residential Land Use: open space stormwater Employment Land Use: residential employment Land Use: Land Use: stormwater other Open Space residential Land Use: residential employment residential other open space employment Stormwaterresidential employment space employment Land Use: open stormwater open space employment open space Other stormwater residential open space stormwater stormwater other open employment otherspace stormwater other other open space stormwater other stormwater other dwellings other dwellings

1 1 11 2 1 12 7,211

1 1

7,211

dwellings dwellings

dwellings 1: .81 .81 1: dwellings 7,211 workers : Jobs dwellings dwellings dwellings jobs 1: .81 8,809 jobs

1: .81 1: 7,125 .81

3 3 33 3 3 5,613

1: .83

1: .93 1: .93

7,125

7,211 7,211 1: .81 1: .81

1: .83 1: .83

7,211 8,809 7,211 7,125 1: .83 .83 1: 8,809 1: .81 1: .83 1: 8,823 .81

jobs 255,916 stormwater jobs

stormwater storage (m3) stormwater (m3) stormwater storage 255,916

222,135

7,125 8,823 7,125 5,613 1: .93 .93 1: 8,823 1: .83 .93 7,863 1:1:.83

8,823 8,823 8,823 7,863 8,823 222,135 222,135

215,064

[d = 0.5m] 222,135 255,916 215,064 [d =222,135 0.5m] 222,135 255,916 storage (m (m )) storage [d == 0.5m] 0.5m] 11.85% 10.29% [d 222,135 255,916 222,135 11.85% 10.29% stormwater stormwater 255,916 11.85% 10.29% 9.96% 33

11.85% (m ) storage (m3) storage stormwater [d = 0.5m] stormwater

10.29%

9.96%

5.93% 5.14% 0.5m] (share5.93% of land) [d =11.85% (share of land)

5.14% 9.96% 10.29% 5.14% 4.98% 10.29% 10.29%

3

3 stormwater

) storage stormwater storage [d(m 1m] share of site area [d == 1m] stormwater 3 stormwater stormwater 11.85% ) storage (m storage of land) storage when d = 1m (share storage storage (m3) 5.93% (share of land) [d = 1m] stormwater stormwater storage 5.93% storage (share of land)stormwater

[d == 0.5m] 1m] [d [d = 1m] [d = 0.5m] 5.93% 10.29% 11.85% [d = 0.5m]

11.85% [d = 1m]

5.14% [d = 1m] 11.85% 5.93% [d = 1m] stormwater 49% 42% (share of land) storage 5.93% impervious storage impervious (share of land) [d =5.93% impervious 1m] stormwater impervious cover (share of land) cover cover 49% 42% cover storage impervious (share of land) cover impervious

83

cover impervious impervious cover cover

impervious

49% 49%

49% 5.93% 49% 49%

49%

Scenario Three Low Density New Town + WSUD

2 2 2 23 2 23 7,125 5,613 1: .83 7,125 7,125

8,809 8,809 8,823 8,809 8,809 8,809 255,916 jobs 255,916 jobs

jobs jobs jobs

7,211

Scenario Two Medium Density New Town + WSUD

4.98% 10.29% 42% 5.14%

41%

42% 5.14% 5.14%

41%

42% 5.14%

5,613 5,613 5,613 5,613 7,863 5,613 7,863 1: .93 1: .93 1: .93 1: .93

7,863 7,863 7,863 7,863 215,064 215,064 215,064 215,064 9.96% 215,064 215,064 9.96% 4.98% 9.96% 4.98% 9.96% 9.96%

9.96% 41% 4.98% 41% 4.98% 4.98%

42% 42%

41% 4.98% 41% 41%

42%

41%

Figure 40: Summary of scenario results (Lau, 2017)

FROM GREEN BELT TO BLUE SIEVE

MASTERS DESIGN REPORT

6.4 Integrated Infrastructure Design The design of infrastructural strategies is part of the ‘Conceptual Site Layout’ in Stage C of the WSUD conceptual design process. Although ‘land use scenarios’ precede this section of the report, these processes have been developed iteratively and are shown separately for clarity. WSUD guidance does not detail conceptual site layout methods, therefore decisions that were made are explained throughout this section. The overall design process (Figure 41) illustrates how each piece of the analysis informed a design decision.

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SLOPE ANALYSIS

FLOW DIRECTION ANALYSIS

POTENTIAL DETENTION AREAS

ELEVATION

100M BLOCK OVERLAY

STREET NETWORK

MATURE CANOPY COVER

STREAMS + WETLANDS

GREEN INFRASTRUCTURE NETWORK LAND USE SCENARIOS

BEST PRACTICE ASSESSMENT

STORMWATER ASSESSMENT

BMP TREATMENT TRAIN

BLUE INFRASTRUCTURE NETWORK

NEIGHBOURHOOD UNIT

15 MIN PARK ACCESS

SOCIAL INFRASTRUCTURE

INTEGRATED BLUE + GREEN + GREY Figure 41: Overall Design Process (Lau, 2017) 85

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Potential detention areas (Figure 44) are flat parts of the site at lower elevations, where water will tend to accumulate. Hydrology tools in ArcMap 10.4 were used to conduct a slope analysis and flow direction analysis (Figures 42 and 43) using elevation data (raster grids of 50m). The flow direction analysis illustrates the direction that water will flow, from each 50m grid cell. The slope analysis calculates the slope percentage of each 50m cell. In Figure 42, slopes greater than 15% are indicated in red and flat areas (less than 2.5%) in blue.

Station Stream

East South East South South West West North West North North East

Slopes Flat > 5% > 15% < 15%

Figure 42: Flow Direction Analysis

Figure 43: Slope Analysis

(Lau, 2017)

(Lau, 2017)

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0

2.5m Contours Potential Detention Areas Flow Direction Slope (low to high)

0.125 0.25

0.5

0.75

1 km

Figure 44: Potential Detention Areas (Lau, 2017)

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M1

Mo

tor wa y

Bro

ug

hto

nB

roo

k

Aspley Guise Station

0 km

0.5

Existing Motorway Existing Major Streets Existing Minor Streets Proposed Grid Layout

1

Figure 45: Street Grid Layout (Lau, 2017)

The proposed street grid layout (Figure 45) was derived from the slope analysis, existing street networks and what is considered walkable (100m x 100m) overlay.

Steep slopes (greater than 15%) are difficult to manage from a stormwater infrastructure perspective, and are avoided. Runoff velocity can be achieved by aligning streets parallel to contours on slopes between 5-15% and flat areas (less than 5%) can be managed by ‘on-surface conveyance and treatment of stormwater runoff with… at source WSUD infrastructure solutions’ (SEQ HWP, 2009, p. 13).

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M1

Mo

tor wa y

Bro

ug

hto

nB

roo

k

Aspley Guise Station

0 km

0.5

1

Figure 46: Green Infrastucture Network (Lau, 2017)

Streams Potential Detention Areas Mature Tree Canopies Proposed Green Infrastructure Network

89

The proposed green infrastructure network (Figure 46) was informed by a visual analysis of existing canopy cover and wetlands and streams, identified in Land Cover and Ordinance Survey data. The proposed network aims to close the gaps between parcels with mature trees or vegetation and protect aquatic ecosystems using riparian buffers adjacent to streams.

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A matrix of Water Sensitive Urban Design Best Practice Management solutions (Table 18) has been created to inform the design of the proposed blue infrastructure network (Figure 47). The matrix lists each solution, and indicates which WSUD objectives can be met by it, and at which scale it should be utilized. The proposed blue infrastructure network (Figure 48) and siting of best management practice solutions was informed by an understanding of the different stages of stormwater treatment and its relationship to site topography.

The water treatment process using Best Management Practice (BMP) solutions (Figure 48) illustrates that all types of water can be reused, but require differing levels of treatment in order to be reused as either potable and non-potable water. Although this pilot study does not detail infrastructural solutions down to the scale of district or block, this diagram would assist in this process, should it be carried out. Most of the BMP’s have multiple functions, however their primary function is indicated as either to ‘capture, store, treat or infiltrate’, in the diagram. The provision of infrastructure such as dual reticulation to supply appropriate uses with a non-potable water supply will result in the reduction of drinking water treatment (and energy).

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Best Management Practices Demand Management

Strategies

Development/Homeowner Incentives Educational Programs Water efficient appliances/fittings Xeriscaping

Rainwater Harvesting

Rainwater collection / tanks Roofwater harvesting UV disinfection for potable reuse

Stormwater Harvesting

Allotment/precinct tanks Retention/Stormwater Ponds and Lakes (Natural) Aquifer storage and recovery Constructed aquifer storage

Waste Water Treatment for Reuse (Grey/Blackwater)

Greywater Treatment Biofiltration Sewer/Water Mining Dual reticulation / Second supply pipe Sewage Treatment and effluent reuse

Stormwater Quality improvement

Gross Pollutant Capture Devices Sedimentation basins Vegetated Swales / Buffers Sand filters Bioretention systems (Swales, Raingardens) Flood retardation Basins Riparian Buffers Natural Channels Urban Forests Open Space Corridors Constructed wetlands Porous pavements

Table 18: Water Sensitive Urban Design Solutions by Scale Matrix (Lau, 2017)

91

Scale

Landscape

Urban Design

Policy / Programs only

Regional / Catchment

Neighborhood / District

Block

Building/Parcel

Water Conservation / Potable Water Waste Water Minimization Stormwater Management

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Discipline

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Discharge to receiving waters

Riparian Buffers

Waste Stabilization Pond

On-site Detention Aquifer Recharge

Upstream Reservoir

Urban Woodland Natural Channels

Stream Network Built up areas Wetlands Contours Highly productive aquifers Mod. productive aquifers Slopes > 2.5 % 2.5 - 5 % 5 - 7.5 % 7.5 - 10% 10 - 12.5 % 12.5 - 15 % <15 %

Waste Stabilization Pond

Constructed Wetlands Detention Ponds Precinct Tanks Sedimentation Basin Bioretention Systems

Roofwater Harvesting Open Space Corridors Detention Ponds Aquifer Recovery Aquifer Abstraction

Capture Storage Treatment Protection Infiltration / Flood Mitigation

Figure 47: Blue Infrastucture Network at catchment and site scales (Lau, 2017) 92

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BLACKWATER

GREY WATER

STORMWATER

RAIN WATER

POROUS PAVEMENT

VACUUM TOILET COMPOSTING TOILET

DETENTION PONDS

ROOFWATER HARVESTING

GROSS POLLUTANT CAPTURE PRECINCT TANKS MEMBRANE BIORECTOR WASTE STABILIZATION POND

SEDIMENTATION BASIN

BIORETENTION SYSTEMS

CONSTRUCTED WETLANDS

AQUIFER RECOVERY PRECINCT TANK/CISTERN EFFLUENT REUSE

UV DISINFECTION REVERSE OSMOSIS CHLORINATION

NON-POTABLE SUPPLY Potable Quality Non-potable Quality Unsafe for reuse

SECOND SUPPLY PIPE

POTABLE SUPPLY

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Capture Storage Treatment Infiltration / Flood Mitigation

Figure 48: Water Treatment Process using BMP solutions (Lau, 2017) 93

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The proposed Integrated Blue, Green and Grey infrastructure network (Figure 49) combines all of the Constructed wetlands are proposed in analysis in this section, as well as an overlay of social the low lying northern part of the site. infrastructure (indicated in pink).

This would be an appropriate location Social infrastructure here, refers to access to amenities within a neighbourhood unit. The local council requires that urban parks be within a 15 minute (720m) walk from any in the development â&#x20AC;&#x201C; diameter of the pink circle.

This 15-minute shed also indicates service provision of other amenities, which may include a grocery store, school or community facility.

for light industrial uses that could benefit from non-potable water supply and being close to the M1 Motorway.

The primary connectors connect major arterials and provide access to the M1 Motorway, High Street, rail station, parks and neighbouring town. They are New open spaces make up 36% of the total site area multi-modal streets that move buses, cars, bikes, (as per scenario two) and are situated based on potential pedestrians, water and green infrastructure. The scale detention areas, the proposed green infrastructure of the development would not warrant the construction of additional light rail infrastructure. Instead, the network and their relationship to each other. development would require a frequent and well distributed bus network, providing access to the rail station from each neighbourhood.

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M1

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Figure 49: Integrated Green, Blue and Grey Infrastructure (Lau, 2017) 95

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PART III The Metropolitan Blue Sieve

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07.

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CO N C LU S I O N

7.1 Discussion London’s current housing crisis, and what may become a water crisis, are two challenges that need to be urgently addressed. The region is already considered ‘seriously water stressed’ (Environmental Agency, 2008) and projections indicate that one of the greatest impacts of climate change will be increased vulnerability to water supply and flooding. Haphazard housing growth in the MGB and the trend towards commuting beyond the MGB are indications that London’s economy and population operate at the region.

Current planning policy and strategies do not operate at a scale that can address these issues. The devolution of power has led to policies like ’duty to cooperate’, and ‘locally led garden cities’. These mechanisms, which defer to local agendas and control, by their very nature will not be able to address issues occurring in the London region.

The two major strategies to address the region’s housing shortage is to build on brownfield sites within the boundaries of Greater London, and to invest in regional High-speed rail (HS2). Brownfield sites currently have non-residential uses, and redevelopment is a long and complex process to negotiate. High speed rail will not address the needs of those wanting to remain in the capital.

The Metropolitan Green Belt (MGB) is blamed for exacerbating London’s affordable housing crisis, as it locks up the supply of surrounding land. An argument against developing on the MGB, is that it provides ecosystem services, critical in the context of climate change. This study set out to examine the effectiveness, condition, policy and limitations of the MGB, to understand whether its benefits can be further expanded to address the region’s current and future challenges.

It did so using three primary methods. The Natural Assets method was used to identify potential green and

blue infrastructure networks that provide ecosystem services in the region. A spatial analysis, using GIS was used to identify parts of the MGB that did not threaten aquatic ecosystems, and could therefore be considered for development. Third, the WSUD conceptual design process was simulated to test this framework on a pilot site in the study region, and understand the implications of this approach on green field developments.

An analysis of the study area, using the Natural Assets method revealed that the green infrastructure network in the MGB is dispersed, largely fragmented, yet at the same time contains areas with potential green infrastructure cores that do not fall within protected areas. This is unsurprising for two reasons. Over 60% of the MGB is related to agriculture, which requires road access and whose land cover is not considered as green infrastructure. Secondly, Green Belt policy does not require land owners to maintain any environmental standards. For green infrastructure to perform to its potential, it has to adhere to particular dimensions and configurations (large, connected cores and corridors).

This analysis suggests that the MGB, in its existing condition, does not have a robust green infrastructure network and therefore its ability to provide ecosystem services is limited.

Green Assets were mapped by combining the identified green infrastructure network with sites protected by other designations (e.g.. parks or ancient woodlands).

Blue Assets map were mapped by combining flood plains, riparian corridors and groundwater recharge areas. Water-sensitive areas (WSA) combined green and blue assets and are characterised as areas that already do, or have the potential to, provide water-related ecosystem services. WSAs make up make up approximately 35% of the MGB. The finding in this study of perhaps most concern is that, over 150 approved development proposals (CPRE, 2016) fall within these areas. This figure is based on the centre-point of a development 98

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proposal overlapping with water sensitive areas, rather than a site boundary, which suggests there may be many This observation demonstrates that new more. development can take advantage of A spatial analysis was used to defensively map areas with ecological or cultural value, which demonstrates an approach planners might use in coordinating development across the region. The factors selected depend on a community’s goals and values, rather than a prescribed method, particularly in relation to cultural value. The strength of this method is its ability to consider a large number ecological factors (using publicly accessible data) to make decisions about development.

The WSUD conceptual process required an in-depth site analysis, using methods that are not typically part of the planning or urban design process. Hydrological analyses typically get carried out by engineers or landscape architects, and usually later in the development process.

This study illustrates the role that a hydrological analysis for example, plays in the decision to site infrastructure for a water sensitive development. The design of the road networks, based on WSUD principles resulted in a street pattern dissimilar to the modern street grid.

Interestingly, the existing street networks fit well with WSUD principles, which is not surprising since the village of Aspley Guise was established before the advent of the automobile.

The pilot study near Aspley Guise station presents a revised urban design method for green field site design, based on WSUD principles. It shows that comprehensive stormwater infrastructure can be integrated into new developments without requiring significant additional space. This observation is contingent on spatial requirements for open space, as shown in the land use scenarios. Stormwater infrastructure can therefore be integrated into public open space, if sited appropriately.

the ecological and economic benefits derived from WSUD design, and still be affordable, if designed in, at an early stage.

It was not in the scope of this study to perform a cost analysis of WSUD solutions, but a number of assumptions support this argument. First, if there are no significant spatial requirements for stormwater infrastructure, other (economically productive) uses are not compromised. To put this in context, a housing association or developer would not have to choose between a few more units or stormwater infrastructure. Second, the storage assessment reveals that the development could deliver a secondary water supply source by dedicating 10% of the land area to water storage (based on a depth of 0.5m).

Public rights of way typically account for more than 10%, therefore if storage infrastructure was integrated locally into streets at the same time as other utilities, the secondary supply network would be significantly cheaper than if infrastructure is deployed later15. Third, as municipal water costs increase, providing a secondary water source for non-potable uses provides long term cost savings.

In summary, the analysis in this study presents a method for the strategic co-ordination of regional development and an urban design framework for the development of ecologically sensitive New Towns. The Metropolitan Green Belt is an underutilized resource – with over a third of its land that can better perform to protect the region’s water resources and a rail network with 78 stations in undeveloped areas.

15 The challenge with stormwater capture and reuse strategies is often owed to the cost of storage (e.g.. cisterns) since the cost of water does not justify this type of investment.

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7.2 Proposed Indicative Strategies Establish the Thames River Basin Regional

Local planning would be coordinated by catchments within the Thames River Basin as shown in Figure 50.

Authority (TRBRA)

Initial responsibilities for the regional planning team would be:

As its name suggests, the TRBRA would be a regional governmental organisation, made up of elected board members and a regional planning team. An accountable and transparent organisation, with the power the access funding and implement plans is essential to the success of the strategies that follow. This river-basin-based governmental authority would oversee the equitable and resilient management of growth and natural resources, in the Thames River Basin. The authority’s role would be to plan, fund and integrate regional infrastructure including housing, transportation, parks and water.

−− To develop a strategic long-range plan for the Thames River Basin in collaboration with catchment based planning units. −− To work with Transport for London (TFL) and British Rail to finance and upgrade regional lines and stations. −− To study the Water Sensitive Cities Australian policy initiative, and consider the applications and implications for the UK. To develop water sensitive design standards for brownfield and greenfield sites in the UK.

Greater London River Network Thames River Basin

Figure 50: Catchment-based planning Units in Thames River Basin (Lau, 2017) 100

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The Metropolitan Blue Sieve Park System

This regional park (Figure 51) would be one of the largest parks in the nation, but unlike the traditional, contiguous parks like Lake District and New Forest, it would be a patchwork of programmed and protected, natural and urban aquatic ecosystems, that connect the regions ecological and cultural assets. Its goal would be to foster ecosystem and community health through public recreation, education and land stewardship. The strength of this park is that, it would enhance aquatic ecosystems across the region, by working with adjacent land uses, while also distributing access and providing recreational space to urban and rural areas. Once established, it could be managed by the TRBRA or handed over the National Parks UK.

Initial tasks for the TRBRA would be: −− To develop land acquisition strategies and conservation agreements −− To support Natural England in developing and funding environmental stewardship and land management programs for farmers. −− To connect with educational institutions and encourage them to conduct research in parts of the park.

Proposed Blue Sieve Network Proposed Regional Blue Parks AONB Ancient Woodland/NNR National Parks Urban Areas Greater London

Figure 51: Blue Sieve Park System (Lau, 2017) 101

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Framework for Ecologically Sensitive New Towns through development corporations

This strategy proposes the development of ecologically sustainable New Towns, in proximity to areas in the region with a high demand for labour. Additionally, it proposes investments in rail infrastructure for New Towns and strategic corridors. 25 sites were identified as potential development opportunities, based on the methodology described in section 5.2 of this report16.

Potential development opportunities are characterized as existing rail stations in the Metropolitan Green Belt that do not intersect Grade 1 or 2 soils, and are not in, what is referred to as Water Sensitive Areas. The 25 sites include Aspley Guise, How Wood, Welham Green, Bricket Wood, Ponders, Laindon, Longfield, Farninham Road, Chelsfield, Penhurst, Hover, Edenbridge Town, Godstone, Salford, Betchworth, Chipstead, Banstead, Clandon, Shalford, Milford, Ewell East, Hersham, Esher, Upper Halliford, Kempton Park.

Figure 52 shows the 25 sites in relation to the towns that have continuously experienced job growth. A recent study on the UK’s 65 largest cities found that Milton Keynes experienced the most job growth between 2003 – 2014, followed by London and Cambridge (Centre for Cities, 2015). This framework proposes improvements and expansion to the 25 rail stations, which would receive New Towns (indicated by red circle) and increasing the capacity and frequency of trains to rail lines with increased ridership (thick red line). Two new routes are proposed (red- dotted line), which will connect Cambridge, Milton Keynes and Oxford to London via Luton – the 4 towns that have experienced the most job growth over the 11-year period.

16 26 sites were originally considered but Heathrow Terminal 5 was removed from the selection

At each station, New Towns of 7,500 – 15,000 new homes (and supporting community services) would be planned and delivered by not for profit development corporations. These development corporations would focus on the local financing, planning, design and delivery of Ecologically Sensitive New Town’s within catchments in the Thames River Basin. The government’s recent announcement to support development corporations is step in the right direction, but commitment to a much larger investment will be required to enable significant development. Early New Town’s were developed using the development corporation model, and the region has a long history of successful developments, including Milton Keynes, Stevenage, and more recently, the London Legacy project (Olympic Park). They would oversee the day-to-day detailed development process, working with developers, housing associations and homeowners.

Strategies to reduce the cost of development and housing:

−− Access to national government backed, low-interest loans for the upfront land purchase and infrastructure investments −− Maintaining affordability in perpetuity by retaining land ownership the development corporation or transferral to a community land trust −− Priority allocation of at least two thirds of new housing to households at or below the median income −− Priority to first time buyers over investment mortgages −− Transportation subsidies based on accessibility to job centres

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Airports Planned Stations Planned Routes (Cross Rail + HS2) Existing Rail Stations in MGB Existing Rail Network Metropolitan Green Belt Thames River Basin Greater London

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Proposed Route Upgrades Proposed New Connections Proposed Station Upgrades Job Growth % change (2004 - 2013)

Figure 52: Metropolitan Strategic Framework (Lau, 2017) 103

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7.3 Implications and Final Thoughts

This framework has the potential to make a significant impact on the region’s affordability crisis. If each of the 25 New Towns builds an average of 10,000 units, the region gains 250,000 new homes. The regional target is to build 40,000 new homes per year, or 65,000 per year to catch up with the backlog, for the next 10 years.

This strategy would provide for approximately 40% of the 10-year target including backlog.

This study highlights the social and environmental benefits that can be derived when making decisions regarding, where, how, and for whom we build - and where, and what we protect, is strategically coordinated.

The recommendations put forth, call for a dramatic paradigm shift, with regards to planning in Metropolitan areas. Green Belt reform alone will not be able to address the regions challenges, but the mechanism itself provides an opportunity to both develop and protect thousands of hectares of land, within the constraints of existing policy. The national policy, which applies to 13 Green Belts across England and Wales, currently allows for development under ‘very special circumstances’ (Department for Communities and Local Government, 2012). In the recommended scenario, it would be up to the River Basin Authority, to determine what ‘special circumstances’17 were for their region. Affordable housing would certainly be considered as special circumstance in the Thames River Basin.

This study contributes to the field of regional planning and urban design in two important ways. First, it reexamines the relevance of Green Belts and Garden Cities in today’s context. Green Belts which have been popular, and for the most part, successful planning tools which continue to be proposed in cities around the globe today. The London region has a unique set of circumstances, yet the findings and recommendations in this study are applicable Metropolitan regions in the UK and beyond. Second, this study focusses on the role of water, and its influence in the planning and design of new communities. The need for ‘sustainable development’ in the context of climate change, is widely accepted in the field, however much of the focus and innovation has been toward the reduction of carbon and Green House Gases (GHG). Although water recycling and conservation are incorporated into Building Research Establishment Environmental Assessment Method (BREEAM) and Leadership in Energy and Environmental Design (LEED) certifications , a comprehensive understanding of water’s interaction with the built environment is often overlooked.

17 Predominant sustainability certifications in the Europe and the United States.

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VITA

Tatumâ&#x20AC;&#x2122;s work engages in design towards social and environmental justice. Prior to completing masters degrees in Urban Design and Community and Regional Planning at the University of Texas, Tatum recieved a Bachelor of Architecture from the University of Witwatersrand in South Africa and a Master of Art in Architecture of Rapid Change and Scarce Resources from London Metropolitan University in the U.K. She has 10 years of professional experience from Johannesburg, London and Austin, which includes research, publishing, teaching, architectural design, community engagement and urban planning.

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