Planning the Sustainable City: Lessons from the past

Paper presented at the ISUF 2003 Conference Marat-Mendes, T. (2003) ‘Planning the Sustainable City’, 10th International Seminar on Urban Form. ISUF 2003: The Planned City?, Castelo Svevo, Bari, Italy, Trani, 3-6 July 2003, vol. III. ISBN 88-7329-043-4. pp. 916-922.

Planning the Sustainable City: Lessons from the past Teresa Marat-Mendes ISCTE, Área Cientifica de Arquitectura e Urbanismo Av. das Forças Armadas, 1649-026 Lisboa, Portugal telf. 00351217903060, fax. 00351217903920 e-mail: [email protected]

Abstract This paper attempts to bring new knowledge into the analysis of sustainable urban form from a new perspective: i.e., the analysis of the physical dimensions of urban forms that had the ability to adapt and transcend over time in a sustainable way. Thus, it describes an original method recently applied in a comparative study of three well established examples of European planned development. This study evaluated the physical dimensions of urban form or ‘ground rules’ that had the ability to change and adapt over time. These ground rules govern order and complexity, shape, size, dimension and spatial arrangement; properties that appear to determine flexibility and adaptability over time, hence they possess qualities of sustainability that need to be understood. This paper concludes by assessing the performance of the three case studies in terms of sustainability and argues that adoption of the proposed methodology would assist all those concerned about the sustainability of urban development proposals, and that could be used as guidelines for the lay out of new urban spaces or in the regeneration of existing ones. Key words: sustainability, urban form, flexibility, adaptability, continuity and change.

1. Introduction History contains an extensive catalogue of towns and cities that seem to have coped with the processes of social and economic change without substantial alteration to their fundamental built forms, while others seem to have coped by more substantial built changes within an urban framework that has remained intact. Their layout and built form principles established the rules that regulated development in order to absorb urban growth and as such possess qualities of sustainability that need to be understood. By a comparative analysis of three historical examples of planned urban development the study aimed to identify some practical reasons for their sustainability. These are Lisbon’s Baixa of Eugénio dos Santos (1756), James Craig first New Town of Edinburgh (1767) and Barcelona’s Ensanche of Cerdà (1855).

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2. Defining the Sustainable Urban Form Although the term sustainability has been interpreted and used in several contrasting ways, a broad consensus emerged in 1987 in the Brudtland Report where sustainable development was defined as “development that needs to meet the needs of the present without compromising the ability of future generations to meet their own needs” (WCED, 1987, p.8). As a result, international attention focused on how to assure the implementation of sustainability and in 1992, at the United Nations Conference- The Rio Summit, a widespread Agenda was established urging all countries to achieve sustainable development. Nevertheless, although it seems to be agreement on the sustainable development definition, there is less consensus on how this latter term can be translated into development ‘on the ground’ (William et all, 2000), i.e., on the establishment and identification of the most sustainable urban form. Contributing to this debate, recent research (MARAT-MENDES, 2002) has attempted to bring new knowledge into the analysis of sustainable urban form, but from a new perspective: i.e., by analysing the physical dimensions of urban forms that have the ability to adapt and transcend over time in a sustainable way. Ultimately, it defined a sustainable urban form as one that has the capacity of surviving the processes of change, and at the same time provides environmental quality which responds to the variety of settlements and contexts over different periods of time. 3. The Methodological framework This work has acknowledged the reading of the urban processes as determinants for the analysis of change in the urban environment. Thus, it proposed a new methodology that consists on comparative analysis in order to identify changes that have been taken place over time. This methodology was applied in three identified case studies (above described), which proved to be survivors of several processes of economic, political and cultural change. The reasons behind the selection of these case studies, apart from the ability of surviving processes of change, was that they appear to contain some contradictions between then. The plan of Lisbon’s Baixa Pombalina of 1756 and Edinburgh New Town of 1767 were initiated within 11 years, but while their architectural and legislative determinism are similar they were based on very different physical characteristics. In addition, while the First New Town of Edinburgh’s physical characteristics seem to get closer to those of Barcelona’s Ensanche by Cerdà in 1855, their architectural and legislative

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determinism contain no similarities. Moreover, the adopted methodology aimed to embrace the overall urban environment of each case study, where, permanence and change of the built environment were indeed the guidelines that developed the present work. The identification of the original plan and the legal regulations that determined the physical shape of those case studies, at the time that were implemented, were indeed fundamental to the comparative analysis with the present physical situation of their urban environment. Finally, the adopted methodology can be characterised in the following sequence of points: 1- A survey of each case study in order to identify the nature of architecture, urban form and socioeconomic for each case study at different periods, from the implementation of the plan until today. Thus is was possible to identify and isolate the Plan Principles, i.e., the ‘Ground Rules’ inherent to each case study, at the time they were conceived, prior to their implementation; and the legislation that facilitated each plan and defined the physical characteristics at the time of the plan’s formulation, implementation and immediately after it. 2 - For each case study, a comparative analysis was now undertaken between all the evidences and information at two different levels. One refers to the changes occurred in the physical context, and the other refers to the changes occurred at the socio-economic level. Relatively to the physical context, various analysis were undertaken as well in order to systematise and distinct the dimensions of physical change that occurred in each case study, i.e., changes occurred at a ground level, and changes occurred in the vertical third dimension. Thus this allowed to identify for each case study the physical changes occurred to the Plan Principles, from implementation to the present, by isolating the physical characteristics that have changed, from those that did not; Changes that occurred in use and ownership were subject of the socioeconomic analysis. Later, following the identification of changes for each example, it was needed to perceive how and why the above physical and socio-economic changes occurred and what enabled such changes to occur. 3 - A Comparative analysis between all the evidences of the three case studies was now undertaken in terms of physical and socio-economic analysis. Therefore, it was possible to identify the physical qualities, or the ground rules, of the different urban patterns, the dimensions of urban form, whether they are adaptable and may be deemed to be sustainable.

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For better understand the application of the methodology, the following tables shows the identified Plan Principles of each case study (Table 1), and the physical changes occurred in the general areas (Table 2) and the blocks of the three case studies (Table 3) in a comparative manner.

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Table 1. Some ‘Ground Rules’ of Baixa, New Town and the Ensanche plans. Plan Principles

Lisbon / Baixa

Edinburgh / New Town

Barcelona / Ensanche

Date of implementation Total area of the plan Grid shape Grid size Neighbourhood size Neighbourhood walking distance, from centre to edge Street widths

1756 319,346m2 Rectangular 36m x 81m 860m x 270m 2.31minutes (east-west) 5.38minutes (north-south)

1767 408,089m2 Rectangular 204m x 108m 1100m x 360m 6.88minutes (east west) 2.25minutes (north- south)

1855 21,761,300m2 Square 133m x 133m 665m x 665m 4.13 minutes (north-south and east-west)

11m 8m 14m 9.5m

50m (diagonals) 20m (both directions) 10 to 20 m (secondary streets) (both directions)

Pavement widths

2,2m

Squares (public spaces)

Comércio Square 34,560m2 Rossio Square 16,000 m2 25m x 71m (1775m2) 33m x 59m (1947m2) 43m x 59m (2537m2) 8 but variable Variable

30m (east-west) 9m (east - west) 8m (mews) (east-west) 24m (north south) 5m (mews) (north south) 3m 1.5m St Andrew’s Square 103,65m2 St. George Square 109,228m2 25,000m2 (180m x 139m) 8,368m2 (107m x 78m) Variable Variable

20 but variable 6m (minimum acceptable) 13m (in 1859 regulations) 20m (minimum acceptable) 40m ( in 1859 regulations)

Block sizes Number of lots per block Lot widths Lot depths

Ratio of built area, street area and unbuilt area in the block

(north south) (north south) (east-west) (east-west)

10.5 m (25x 71m blocks) 14.5 m and 12m (33m x 59m block) 19.5 m and 12m ( 59m x 43m blocks) The 12m lot depth relates to the lots located in the narrowest side of the blocks 89% built area 11% unbuilt area 0% streets or lanes

Ratio of built area and open area in the lot

100% for construction

Building Width Building depths

Variable 10.5m

Maximum building height

24.40m

Number of storeys per building

5 4

Type of buildings Distance between buildings and pavement Distance between opposite buildings

Flats 2 flats per floor or 1 flat per floor 0 14m 8m 4m (courtyards)

41m (main streets - east west) 30m (main streets north –south) 15m (mews)

5m Street nodes (1,931m2) Large Squares (variable) 113m x 113m (12,377m2)

50% for construction and 50% for gardens

41% Built area 42% Unbuilt area 17% streets and lanes 64% for construction 36% for green areas 50% – 50% in mews and side streets Variable 15m 11,6m (main streets) 6.67 (secondary and side streets) 14,64m from basement level (main streets) 3 visible from street level ( main streets) However there were 5 storeys. Included 1 basement and 1 attic. 2 visible from street level in side streets but there were 4 storeys. Included 1 basement and 1 attic. Terraced houses (One family per house) 3m (on main streets) (N-S and E-W) 0m (on other streets) 36m (main streets) 9m 30m 42m (courtyards) 20m (courtyards)

53% Built area 47% unbuilt areas 0% street or lanes 50% for construction 50% for green areas variable 20m (1859) 28m (1865) 16m (in 1855) 28m (in 1865) 3 4 5 6 Detached houses Terraced Houses Semi-detached houses 0 20m 73m 200m

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Table 2. Changes in the general areas of the three plans. Lisbon / Baixa


1756

At present

Growth Rate

1767

At present

Growth Rate

1855

At present (a)

Growth Rate

166,462m2 (52%)

167,764m2 (53%)

-1,302m2 (+1%)

80,128m2 (20%)

182,170m2 (45%)

+102,044m2 (+127 %)

6,969,356m2 (32%)

9,912,599m2 (45%)

+2,943,243m2 (+42)

Other Constructions (1%)

Other Constructions (0%)

(-100%)

Street Layout

117,212m2 (37%)

123,930m2 (39%)

+6,718m2 (+6%)

192,558m2 (47%)

174,788m2 (43%)

1,7770m2 (-9 %)

7,529,692m2 (34 %)

7,575,000m2 (35%)

+45,308m2 (+0.6 %)

Unbuilt Area

31,920m2 (10%)

27,652m2 (8%)

-4,268m2 (-13%)

135,403m2 (33 %)

51,089m2 (12%)

-8,43142 (-62 %)

7,262,255m2 (33 %)

4,319,012m2 (20%)

-2,943,243m2 (-41%)

319,346m2

319,346m2

0%

408,089m2

408,089m2

0%

Built Area

Total Area (a) (b)


21.761,300m2 7,470,000m2

-65.6%

(b)

Areas calculated as if the plan had been fully implemented, but the changes are identified based on what has actually been taking place in the Ensanche. The total area indicates actually the area that was implemented and not the area of the plan. That would have been 21,761,300m2 as well.

Table 3. Changes in the blocks of the three plans. Lisbon / Baixa



1756 (as planned)

At present

Growth Rate

1767 (as planned)

At present

Growth Rate

1855 (as planned)

At present

Growth Rate (a)

Built Area

1,575m2 (89%)

1,725m2 (97%)

+150m2 (+10 %)

10,280m2 (41%)

19,110m2 (76%)

+8,830m2 (+85%)

4,128m2 (33%)

8,664m2 (70%)

+4,536m2 (+110%)

Unbuilt Area

200m2 (11%)

50m2 (3%)

-150m2 (-75 %)

Total 14,720m2 (59%)

Total 5,890m2 (24%)

Total -8,830m2 (-60%)

8,248m2 (67%)

3,713m2 (30%)

-4,535m2 (-55%)

10,570m2 inner courtyard (42%)

2,114m2 inner courtyards (9%)

-8,456m2 inner courtyards (-80%)

12,377m2

12,377m2

0%

(113x113m)

(113x113m)

4.150m2 streets (17%)

Total Block Area

1,775m2 (25x71m)

1,775m2 (25x71m)

0%

25,000m2 (180x139m)

3,776m2 streets (15%)

-374m2streets (-9%)

25,000m2 (180x139m)

0%

4. Principal findings on the Search for a Sustainable Urban Form

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The three case studies contain some significant contributions to the analysis of sustainable urban form. Sustainability can be read through uses and changes that have occurred in the urban form. The results in the comparative analysis contain findings that are important to the assessment of urban forms and their sustainability. These contributions are significant as the three urban examples have worked well over time and continue to be valid today and therefore contain lessons of sustainability, both in their usage and in their ground rules. This work has confirmed that the Baixa plan has responded well to change in a sustainable way. According to Lewis (2000) sustainability is important in the establishment of an effective urban regeneration policy, where re-utilisation, adaptability and flexibility should be possible within the urban fabric, thus creating a self-regulating urban environment and a sustainable one. In this regard Baixa has responded well by regenerating its buildings in a strategy that has sought to prolong the utilisation of the buildings with which they were first conceived. Branunfels (1988) remarks on the relationship between governmental ideals, power and urban form. This research has shown that the assurance of plan principles when a plan is implemented depends on the political power behind the implementation and the will to fulfil it. Moreover, the cessation of respect or control through regulations has significant consequences on the level of change that can occur in an urban form and consequently on its sustainability. This work has also confirmed that changes in the physical forms of cities are related to the social and economic forces that have been taking place over time, as argued by Meller (1987). MacCormac’s assertion (DAVEY, 1980) that the desire for individual expression in housing is inverse to the acceptability of its overall image appears to be true in both Edinburgh’s New Town and Lisbon’s Baixa, aided by conservation measures to ensure that little is changed. Moudon’s (1986) findings on San Francisco are also confirmed in that large deep blocks are intensified by the assertion of alleys and by subdivision of the interior. This is confirmed in both Edinburgh’s New Town and Barcelona’s Ensanche. This work argues that the development of an urban form that permits large deep blocks should be controlled by administrative regulations to ensure that change can occur in a sustainable way. This research argues that small blocks are preferable because they control the levels of change in a more natural manner without resource to additional legal regulations. Thus, the sustainability of an urban layout might occur naturally, when based on the ground rules that delineated it, or artificially when enforced by legal measures to avoid situations that transform it in an alien manner. 7


This work also agrees with Papageorgiou’ s (1971) argument that the sustainability of an urban form can only be achieved if its urban spaces correspond to lively urban places with a unique atmosphere. In this respect Baixa, the New Town and the Ensanche are all sustainable examples of urban form. Supporting this is the fact that these urban places are recognised as important tourist and socially liveable places. Nevertheless, the significance of sustainability differs in scale in the three case studies. The New Town and the Ensanche contain 24 hour long activity, whereas Baixa looses its social importance at night and consequently becomes unsafe. While the public avoids Baixa at night, the New Town and the Ensanche continue to be fully used. Clarence Stein’s (1966) findings on neighbourhood walking distances are supported by the three case studies; they possess dimensions that are comfortable for their inhabitants and are important as sustainable urban forms. The study also confirmed Scoffham’s argument (1984) that space is the asset that permits change to occur. However it also argues that change can occur and not be evident, in which case there is no need for space and space becomes unimportant for the occurrence of change. This did not only occur in small lots as was argued by Moudon, but also in larger lots. For example, changes were not evident in the New Town along Queen Street, or in Baixa buildings along the majority of its streets. Nevertheless, changes occurred in the buildings of these two plans in similar manner, through the adaptation of internal areas to new uses. Siksna’s (1990) findings on block performance have also been confirmed in this study. Larger block sizes intensify development and encourage the insertion of alleys or arcades. This happened in the New Town and the Ensanche, but did not happen in Baixa where there is a more predictable building form and fine grain urban fabric. This work confirmed other Siksna’s findings. For example, large deep blocks can be intensified by alleys and by the subdivision of the block interior into more lots. In blocks subdivided by streets, the insertion of alleys is more difficult. Existing alleys tend to disappear with the addition of lots or by building on empty spaces within the lots. Arcades occurred in the New Town when several lots were assembled into a single lot creating a through building crossed by a commercial arcade. In the Ensanche blocks that were not originally subdivided by alleys and streets were the ones that changed most, whereas blocks that were originally subdivided by alleys were the ones where change is less evident.

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Comparing Brown and Johnson’s (1985) awareness of the need for comparative studies of morphological similarities in urban form, this work reveals that although the analysed cases are not medieval ones as those of Brown and Johnson, urban layouts from different cultures that permit similar transformations usually produce morphological similarities. 5. Conclusions The main theme of this research has been the sustainability of urban form. An urban form that has the capacity of surviving various processes of change and that simultaneously provides environmental quality that responds to a variety of settlement patterns and contexts over different periods of time can be considered as sustainable. This work has examined the ‘ground rules’ or the urban arrangements, that when allocated appropriately, enable change to occur within the urban layout without major disruption to its original framework. A level of inter-dependence between all parts of the city was seen as a prerequisite for the definition of the city system. Hence, physical elements of urban form such as the grid, street layout, blocks, buildings, lots and façades form the physical features that complement the well being of citizens when allocated appropriately. The first essential parameter to impact on urban space that has emerged from the research is the way in which space is arranged in terms of shape, size and disposition of street layouts, blocks, lots, buildings and façades. Change within specific shapes, sizes and dispositions, is more possible than in others, therefore they have performed better in responding to development requirements. This research has also showed that there is a dynamic between the various physical elements of urban form and that those changes undertaken without concern for the collective space have deep impact on disrespect for the ground rules of the original framework and do not contribute to its sustainability. This study also confirmed that space is the asset that permits change to occur. Urban patterns where changes are most evident are those where change has occurred by unselfconscious adaptation to the pressures of modernisation and speculation. This demonstrates consistency in the shape and size of an irregular grid within which perimeter development has occurred, but has only occurred where space was available for modernisation and speculation to take place. Urban patterns where changes are less evident appear to adapt better over time, because they appear to manifest changes without major disruption to the plan principles that structured them and thereby support the success of the plan. These are more sustainable than the other urban patterns as there is a greater reutilization of structures and materials

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without excessive energy consumption and waste. The ‘ground rules’ for this form of sustainability would appear to be more universal than has hitherto been recognised. Finally, the methodology would be of help in a better general understanding of the limits of control and change in the urban environment and therefore on its sustainability. This would have important implications for planning, architectural and design practice in terms of the establishment of a conceptual basis for the understanding of the ‘ground rules’ that govern urban space. The application in practice of the methodology and the findings of this research would assist both central and local governments concerned about urban sustainability and against which development proposals could be assessed. Therefore, some work should be done to translate the findings of this research into a more accessible methodology. The identification of certain optimal or preferable urban forms and ‘ground rules’ suggests that they might be used as guidelines for the lay out of new urban spaces or in the regeneration of existing ones. Nevertheless, comparisons with other urban forms are important in order to assess whether the findings of this research are as universal as they appear to be.

References BRANUFELS, Wolfgang (1988) Urban Design in Western Europe: Regime and Architecture, 900-1900, The University of Chicago Press, Chicago. BROWN, F. E. and J. H. Johnson (1985) “An Interactive computer model on urban development: The rules governing the morphology of medieval London”, Environment and Planning b, Vol.12. DAVEY, Peter (1980) “Perimeter Planning and its evolution”, Architectural Review, Volume 149, Nº 890. LEWIS, J. Owen (2000) “Architecture and Sustainability”, Quaderns, Nº 225. MARAT-MENDES, Teresa (2002) The Sustainable Urban Form. A Comparative study in Lisbon, Edinburgh and Barcelona, unpublished Ph.D. thesis, The University of Nottingham, UK. MELLER, Helen (1987) Towns, plans and society in modern Britain, Cambridge, University Press, 1987. MOUDON, Anne Vernez, (1986) Neighbourhood Architecture in San Francisco, The MIT Press, Cambridge. PAPAGEORGIOU, Alexander (1971) Continuity and Change. Preservation in City Planning, Pall Mass Press, London SCOFFHAM, Ernie (1984) “Ground Rules – Frameworks for Low Cost and Progressive Development”, International Conference on Low Cost Housing for Developing Countries”, Central building research institute, Roorkee, India, 12-17 November 1984.

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SIKSNA, Arnis (1990), “A comparative study of Block size and form (in selected New Towns in the history of western civilisation and in selected North American and Australian City Centres)”, unpublished PhD Thesis, The University of Queensland. STEIN, Clarence (1966), Towards New Towns for America, The MIT Press, USA. WCED (World Commission on Environment and Development) (1987) Our Common Future, Oxford University Press, Oxford. WILLIAMS, Kate, BURTON, E. and JENKS, M. (2000) Achieving Sustainable Urban Form, E & FN Spon, Oxford.

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