New approaches in urban development How do they work, and do they (potentially) achieve sustainable urban forms?

Transcription

1 New approaches in urban development How do they work, and do they (potentially) achieve sustainable urban forms? HWF 1

2 New approaches in urban development Part of presentation based on the Research Project Urbanising Suburbia Carried out within the framework of City Form (The Sustainable Urban Form Consortium) Funded by EPSRC (Engineering and Physical Science Research Council) under the SUE (Sustainable Urban Environments) Programme Research Team Dr Hildebrand Frey, Co-Investigator Dr Samer Bagaeen, Researcher, (March October 2006) Charalampos Giachis, Researcher, (November - December 2006) Pedro Faria, Researcher, (June - September 2007) HWF 2

3 Content of presentation 1. Theoretical underpinning of research project: the city a modular construct 2. Methodological underpinning of the research project: working with target and threshold values of urban development 3. Developing a tool for the measurement of sustainability levels of urban areas 4. Testing the tool: formulation of regeneration programmes for selected urban areas & comparing it with best practice approaches HWF 3

4 (1) Theoretical underpinning of research project the city as modular construct Urban development issue the need to at least maintain, at best increase, biodiversity and bio-productivity of the biosphere the need, therefore, to protect the countryside from (sub)urbanisation Contradictory responses to issues Pro greenfield development: In the UK, new housing, even new towns, are vital to cope with the growing housing shortage; development on greenfield sites is no problem; there are very large of land reserves Con greenfield development: New housing to be developed on brownfield sites through intensification of existing urban areas to protect the countryside from urbanisation Background to first response the need to accommodate a growing number of smaller households 3.8 million additional new dwellings by 2021 (Barker Report 2004) Ecological issue Nobody questions the need to build additional housing But there are many, including Sir Peter Hall, who argue that there is plenty of undeveloped land and there is no need for it to be protected In the UK, developed land 16.9%, undeveloped land 83.1% (Defra, 2006) The land needed to build 3,8 million new dwellings would be 123,853 ha, i.e. only 0.5% of the total UK land, 1.73% of the total UK semi-natural land; SO WHAT? Background to second response These are spurious arguments: the consumption levels of the residents in the southeast of England alone require 55 million ha bio-productive space, 29 times the physical land area of the region and 2.63 times the UK s total undeveloped land (taking stock) There is accordingly a shortage of land not for the reduction of the huge consumption levels of UK towns and cities New housing therefore on brownfield sites in already developed areas > intensification Who is right? HWF 4

5 Traditional approaches to urban intensification and associated problems Developing gap sites, disused areas, subdividing deep plots of land: examples Llewelyn-Davies HWF 5

6 The neighbourhood as smallest entity of urban intensification Intensification of urban areas is only sustainable if their population supports viable public transport and local services and facilities; this requires the population to be large enough and socially sufficiently mixed if local services and facilities in these areas are accessible on foot and bicycle Intensification = not just more urban fabric, more housing, but the generation of urban areas urban quarters, villages, neighbourhoods with their own services and facilities and public transport Programmes for urban development, regeneration, or intensification must therefore be planned as part of urban neighbourhoods that themselves have to be understood as the smallest building blocks of a town or city Sketch of the urban neighbourhood Britz, Berlin, 1925 Planning Department of Berlin HWF 6

7 The traditional city a modular construct of guild quarters / parishes HWF 7

8 UTFR 1999, p.52 - The loss of modularity in the edge areas of today's city HWF 8

9 The neighbourhood as building block of districts, towns and cities The city a modular construct But the city as a whole is unlikely to be compact, more like a more or less irregular network UTFR 1999, p.53 - Reinstating full modularity > a 'compact' city? HWF 9

10 The city as modular construct - the fractal city HWF 10

11 Glasgow's structure of nodes and linkades: a network city HWF 11

12 (2) Methodological underpinning of research project developing a tool for target-based urban regeneration Agenda 21: indicators of sustainable urban development The lack of guidelines and targets (and if there targets, they are formulated such that they can be adjusted to any condition or preference rubber targets); decision making is therefore more or less intelligent guesswork and outcomes are at best uncertain, at worst counterproductive The need to develop a tool with the help of which levels of (un)sustainability of urban areas can be systematically measured Formulation of threshold and target values for indicators relevant for urban regeneration projects The values are derived from UN, EU, and UK government recommendations, UK research and local and continental best practice cases; many of the social and economic values are not yet supported by empirical evidence, but by sound arguments The equivalent existing values of urban areas can be compared with the threshold and target values; the difference between the two set of values forms the basis for a regeneration programme Testing the tool: in the UK, Glasgow and Freiburg Glasgow city centre and beyond, 1960s development without common indicators of a good city, without generally valid targets. The city becomes the expression of a multiplicity of competitive priorities such as traffic management, mass social housing, business interests, energy provision etc.; anything goes but achieved is little more than physical, social and environmental chaos Example of urban development without shared values: Glasgow, 1960s HWF 12

13 What target and threshold values of urban development are Target values of urban development are deemed to be values, a city ought to have to become physically, socially, economically and environmentally sustainable Threshold values are regarded as minimum acceptable values of a sustainable city A sustainable city is one that is able to respond to and cater for the multiplicity of needs and aspirations not just of a section but all its inhabitants while at the same time doing no irreversible harm to the environment and preserving irreplaceable natural resources To develop such targets and thresholds is a complicated and continuous process that requires feedback from each urban development project so that values can be modified and improved or replaced with the help of a growing base of empirical evidence Urbanising Suburbia has attempted to set such a process into motion HWF 13

14 (3) Developing a tool for the measuring of sustainability levels of urban areas The comprehensive investigation of indicators of sustainable urban development would require the following characteristics of urban areas and the city to be covered: Physical formal, spatial, structural, organisational sustainability Social sustainability Economic sustainability Sustainable transport and mobility Environmental / ecological sustainability This is what the 5 research teams of the CityForm Consortium s core programme did The Urbanising Suburbia project would have required the output of the Core Programme as input for the formulation of target and threshold values But projects run in parallel and outputs were not available before the end of the 4 year period of the entire programme Therefore the limitation of the sustainability tool to the planning and conception stage of urban regeneration projects HWF 14

15 Specifying built form, social and economic target and threshold values for sustainable urban areas Built form characteristics The required local services and facilities including public transport The threshold population required to support local amenities The maximum walking distance from edge to centre of the neighbourhood The size, area and development density of the urban neighbourhood Graded densities from edge to centre of the urban neighbourhood Graded densities of urban neighbourhoods according to their location in an urban district, town or city (increasing density from edge to centre of town/city) Vertical and horizontal mix of tenure and dwelling types The development of threshold and target values for built form characteristics was the relatively easy part of the project; values are largely based on urban economics (catchment population for amenities, public transport etc.) and planning responses to functional, social and environmental issues of city development. Some target and threshold values have been published by the Urban Task Force, UK Government departments, and research reports, especially Barton et al. 2003, Shaping Neighbourhoods - A Guide for Health, Sustainability and Vitality. London & New York: Spon Press. Others were taken from best practice case studies. Social characteristics A balanced population age profile A balanced mixture of dwelling types A balanced mixture of tenure types Indicators of the socio-economic balance or imbalance of the neighbourhood population Qualification of people in working age Health conditions of people Deprivation levels No recommended values could be found and the adopted values have been derived from statistical analysis (predominantly Glasgow and Scotland for case studies) Economic characteristics A balance between economically active and inactive people in working age A balanced range of property prices and rent levels in the neighbourhood Again no recommended values could be found and the adopted values have been derived from statistical analysis (predominantly Glasgow and Scotland as well as best practice case studies) HWF 15

16 Table 1 Services and facilities at urban neighbourhood, district, town and city cores indicators target target uses weight source distances Access to local hub amenities (4 forming a m walk Primary school Medical surgery Corner shop DETR 1999, Urban Task Force Report (UTFR) neighbourhood) Nursery school p.31, Research Community park Team Access to neighbourhood amen ities Access to district amen ities Access to town amen ities Access to city amen ities Weight scale: Playground m walk Public house / inn / cafˇ Group of shops / convenience store Post office Community office Community centre and square Access to public transport stop Youth meeting place Adventure playground Sports fields (football, volleyball etc.) Connectivity to other NBHs, district, town and city centres and beyond A permeable street internal network An integrated public transport system 1,500 m Secondary school Playing fields 2,000 m District Centre Superstore / larger shops Leisure Centre Nature space Integrated public transport system Health centre Library Sports centre 5,000 m Cultural / entertainment. centre Higher education General hospital Integrated public transport system up to 20 km Stadium Cathedral City Hall Key museums Major theatre + public facilities University Regional exhibition centre Integrated public transport system 4 absolutely essential 3 essential 2 wanted but not essential 1 not needed DETR 1999 (UTFR), Barton et al.2003, pp96-9, Research Team Barton et al. 2003, pp.96-9, Research Team DETR 1999 (UTFR, p.31), Research Team DETR 1999 (UTFR, p.31), Research Team HWF 16

17 Table 2 Built form characteristics (strategic planning stage) of urban neighbourhood (NBH) indicator target / average / threshold values value source / comments NBH around district core NBH around town core NBH around city core Population target 1,2 7, , , ) DETR 1999 (urban Task Force Report), p.61 2) Research Team Distance edge to centre target m 530 m 530 m scales: average m 600 m 600 m m meter Total area Size of housing land (including local open space & local access roads) 60% of total land threshold m 670 m 670 m target 2 88 ha 88 ha 88 ha average ha 113 ha 113 ha threshold ha 140 ha 140 ha target 2 53 ha 53 ha 53 ha average 2 68 ha 68 ha 68 ha threshold 2 84 ha 84 ha 84 ha Size of non-housing land target 2 35 ha 35 ha 35 ha (communal area, amenities, average 2 45 ha 45 ha 45 ha workplaces, major transport routes) 40% of total land threshold 2 56 ha 56 ha 56 ha Gross population density target 2 85 ppha 102 ppha 119 ppha (population over total land) average 2 66 ppha 80 ppha 93 ppha threshold 2 54 ppha 64 ppha 75 ppha Net population density target ppha 170 ppha 198 ppha (population over housing land) average ppha 132 ppha 154 ppha threshold 2 89 ppha 107 ppha 125 ppha Net dwelling density target 2 67 dpha 81 dpha 94 dpha (at 2.1 persons per household average 2 52 dpha 63 dpha 73 dpha (Glasgow average; to adjusted for other towns and cities) threshold 2 42 dpha 51 dpha 60 dpha Graded target net dwelling overall density 2 67 dpha 81 dpha 94 dpha density 1,2,3 at edge 2 52 dpha 67 dpha 81 dpha (increased net dwelling density from location (25% of edge of NHB to NBH centre) housing land) at intermediate location 2 (50% of housing land) at centre 2 (25% of housing land) 67 dpha 81 dpha 94 dpha 81 dpha 94 dpha 109 dpha ha hectare ppha persons/ha dpha dwelling/ha The average dwelling density of urban neighbourhoods needs to reflect local conditions 1) DETR 1999, UTFR, p.53 (urban capacity, relative density scale) 2) Research Team 3) Barton et al, 2003, p.123 (principles of public graded density) Connectivity 1,2,3 (links to other NBHs, to district, town and city centre and beyond) targets 1,2,3 a permeable street pattern (no cul-desacs, all streets connected) an integrated pubic transport system (local bus stops, LRT nodes, railway stations, airport) 1) DETR 1999, UTFR, p.53 (movement hierarchy from city centre to the home 2) Research Team 3) Barton et al, 2003, p.123 (principles of public transport planning) HWF 17

18 The structure of a neighbourhood: housing and non-housing HWF 18

19 Table 3 Social characteristics of socially inclusive urban neighbourhood indicator location target value weight source / comments Population age profile 20% of population age % of population age UK and England average; close to 16% of age profile age 65 + Scotland average Mixture of dwelling Close to 32% flats The principal types for graded district core 68% family homes (with garden) distinction is between density in neighbourhoods Close to town & city core 56% flats 44% family homes (with garden) family houses with gardens and flats Household sizes 42.0% 1 person households 29.5% 2 person households 14.5% 3 person households 9.5% 4 person households Glasgow average suitable for Govan neighbourhood areas Mixture of tenure types (for equitable distribution of househol ds in need of social housing provision) Qualifications of people in working age Other indicators of poverty and deprivation Weight scale: 4.5% 5+ person households 39% social housing 49% owner-occupied housing of which 29% upper market owner-occupied 20% affordable owner-occupied 42.0% without qualification 21.0% with level 1 qualification 13.5% with level 2 qualification 6.0% with level 3 qualification 17.0% with level 4 qualification Target is also an intensive education and training programme for those without or with poor qualifications % of population with LLTI % of population income deprived % of persons in working age claiming benefits SIMD ranking of neighbour-hood population 4 absolutely essential 3 essential 2 wanted but not essential 1 not needed Target based on the Glasgow average and the survey of property prices in the Govan area of Glasgow, 2006 Target is the Glasgow average to achieve an equitable distribution of underperforming people LLIT = limiting longterm ill-health SIMD = Scottish Index of Multiple Deprivation The target values need to be adjusted to local conditions outside Glasgow HWF 19