Urbanism primarily is about designing, building and transforming settlements based on the changing needs of society. According to Vitruvius these requirements can be classified under three headings: commodity, firmness (or sustainability) and delight. ‘Commodity demands a perfect division of spaces, without impediment for the occupiers, and practical siting. Delight is achieved if the work is attractive and graceful to the eye and if the dimensions of the various parts are evenly proportioned the one to the other. Firmness is guaranteed by laying sufficiently deep foundations, sunk into solid ground, and by a judicious choice of building materials without regard to the costs.’2 Two millennia later, various policy reports refer to functional quality, spatial quality and future quality. Evidently little has changed where urban requirements are concerned.

But the literature on sustainable urbanism fails to make clear what this really entails. It does, however, expand on what constitutes a sustainable development: ‘the rate at which resources and raw materials are used should not exceed that at which they can be replaced by man or nature, and pollution must be kept at a level that the environment can absorb’.3 Following on from this is the definition of sustainable building: ‘to build, and make use of buildings and their surroundings, in such a manner as to minimize damage to the environment, in all phases from design to demolition.’4
Sustainability also means ‘not liable to deterioration’. When this term is applied to urban design it is evidently the place (the city) which is unliable to deterioration. But this is where the inventors of sustainable urbanism are mistaken, because they apply sustainability not to urban design but to the environment. When environment comes to replace urban design, it sets up a one-sided interpretation of the concept of urbanism, fundamental areas of which are not addressed as a result.
The literature on sustainable urbanism also fails to give sufficient thought to the fact that currently 20% of the Netherlands is urbanized, compared with 9% in 1960. In Randstad Holland the urbanized area accounts for almost 30%. One may well ask whether, from a sustainability viewpoint, it is really desirable to increase this percentage by setting further spatial developments in train.5 This particular question has been studied in depth in Dordrecht where, after an extensive public enquiry, it has been decided not to carry out any new building in the green areas, but instead to seek out inner-city sites.6
The way urbanism has been implemented since the war has led to an increased consumption of space per capita. The resulting space shortage is a spatial planning issue at government level. Decisions taken at that level have an enormous impact on the urban design that must be used to effect this spatial planning policy (take the Fourth Report on Spatial Planning in the Netherlands Extra, better known as Vinex).

Sustainable urbanism

A number of publications have recently appeared which address the subject of sustainability in urban design. Bouwstenen voor een duurzame stedebouw (Building blocks for a sustainable urbanism), published by the environmental consultancy Boom, makes 75 recommendations for an eco-conscious urbanism, primarily developed for what are caled ‘development locations’ in current jargon.7 The building blocks are categorized under seven themes: ‘structure’, ‘flora and fauna’, ‘landscape and ground soil’, ‘water systems’, ‘traffic systems’, ‘energy systems’ and ‘domestic waste and the daily living environment’. De duurzame stad (The sustainable city), compiled by De Kleine Aarde (The small earth) addresses similar themes, one of which is sustainable building.8
The examples in these publications read rather like an inventory from which one can pick at random. Each building component is autonomous and is not related to the other components, with the result that users might very well find themselves faced with a dilemma because two such components fail to logically interconnect. For instance the recommendations to ‘make use of passive solar energy and orient the house towards the south’ and ‘build compactly’ are difficult to harmonize. It is an accepted fact that open-row housing does not attain a high density. What then is more important from an environmental viewpoint? Also the suggestion to ‘restrict traffic noise pollution; increase the distance between the road and the buildings which are sensitive to noise’, requires considerable space and is therefore at variance with the need to build more compactly. Thus we often see a conflict between efficient use of space, and space that should be left unused out of considerations of environment and health.
Two examples of projects that include an environmental response built into the urban plan are the Water Board (GWL) site in Amsterdam and De Wijk in Tilburg. Boom of Delft have acted as environmental consultants on both occasions. These two plans are typical of the environmental approach implemented in recently developed residential districts.
For the site of the former Municipal Water Board (GWL) Kees Christiaanse designed a scheme for some 600 dwellings, 14 commercial premises, one cafe/restaurant and a community centre.9 The environmental target-level was determined according to the ‘four variant method’.10  Broadly speaking the environmental themes in this method are the same as those in Bouwstenen voor een duurzame stedebouw. The themes that influenced the urban plan were ‘traffic’, ‘building plots’ and ‘greenery’, and these are manifested in a car-free residential district with a high hook-shaped wall in the northwest corner. On the inside this wall has elevations and outdoor spaces, oriented towards the south-west and south-east. The fact that the site is car-free has permitted public space with a green character. The cycle- and footpaths follwo the same direction as the streets of the adjacent quarter (Staatsliedenbuurt). The scheme also includes a square, a lake, private gardens and communal gardens for the inhabitants of the multi-tiered dwellings in the hook-shaped wall. There has been a symbiosis between environmental concerns and the urban plan as realized.
‘De Wijk’ is an (as yet unrealized) development location of 2700 dwellings situated on the west side of Tilburg, and forms part of the Reeshof Vinex site (12,500 units). It is separated from the other Reeshof residential areas by the Tilburg/Breda railway line. In view of the limited number of dwellings there are to be no separate amenities, with the exception of a new railway station. Government Architect Wytze Patijn is responsible for the structural concept of De Wijk.11 The ‘environment-ambition level’ is determined according to the so-called environment-maximization method.12 This method can be construed as an elaboration of Bouwstenen voor een duurzame stedebouw and is aimed at effecting a consistent implementation of environmental aspects into urban planning strategies. Given the phased structure and the involvement with the planning strategies, environment maximization must serve as a basis for the final urban plan. The method regards the site and the brief as a given. Patijn emphasizes that ‘this method is an analysis method, not a design method, and that the drawings resulting from the maximization provide as few spatial images as possible.’13 Nevertheless there is a tendency to reach organizing principles by proceeding from environmental themes, which can have a far-reaching influence on the final design. This is particularly so in the maximization phase of the themes ‘landscape’, ‘water’, ‘traffic’ and ‘energy’, as well as in the environment- optimization phase in which these four themes are brought together in one map. The last phase of the environment- maximization method is that of integration. The method’s  authors have described this phase as follows: ‘In the integration phase the data on the environment-optimization map are integrated with aspects that are not related to the environment, such as local planning controls or policy-led requirements. This integration is done by the urban designer.’
Interestingly, this method approaches urbanization as an environmental rather than a planning issue. In certain cases the solutions prompted by environmental concerns also contain organizing principles that could influence the urban plan (buildings oriented towards the south, a diagonal as the shortest cycle route). If too many of this type of organizing principle are prescribed, the scheme runs the risk of becoming merely the sum total of so many maximized responses.

Sustainability in urban design

In the book Ideeën voor een duurzame stad durability is interpreted through a reappraisal of urban design, and the model of the sustainable city envisaged in terms of five components: an ecological, a socio-cultural, an economic, a spatial and an infrastructural and cybernetic component (keyed to permanent renewal).14 These five components require an integrated approach. The report Nationaal Pakket Duurzame Stedebouw (National measures for sustainable urbanism), which is to appear this spring, also takes urban design as its stepping-off point by presupposing a division into environmental types (urbanization types) and using that as a springboard for dictating environmental measures.15 This more wide-ranging approach to what sustainable urbanism should entail accords with what urban design has been doing for a long time. Many towns and cities have existed for centuries and, although they are continually changing, more aspects endure than change.16 The changes that do occur over the years relate more often than not to the private sector, the buildings. According to Urhahn and Bobic the history of cities teaches us that urban space is the most constant factor over time.17 Usage, density and architecture may change but the urban space – i.e. the form, and the streets and squares – is much more enduring. If the processes of change (urban transformations) should generate a different dynamic between the private and public sectors, then it is important, not least from the viewpoint of durability, to take this into account during the design process.
Twenty years ago Carel Weeber argued similarly for an autonomous, formal urban plan geared to ordering public space and placing buildings within this order.18 Weeber maintains that the quality of the cityscape is primarily determined by the ‘image qualities’ of public urban space, with the qualities of the buildings playing a supporting role. He cites as examples the Barcelona and Manhattan grids. Jan Heeling speaks in this context of designing the ‘urban floor plan’, with the design of the network of public spaces as a priority issue.19 This network defines the areas (fields) that are accessible for building.
The area around the Vondel Park in Amsterdam is a good example of such an urban floor plan.20 This quarter arose in phases at the turn of the century on the fringes of the existing Vondel Park. If one were to draw up an inventory of the hallmarks which define the sustainability of the area it would include the following: fair-sized houses (two-storey downstairs flats of 150m2, three-storey upstairs flats of 220m2) contained within five-storey perimeter blocks. These houses have a neutral plan, making it possible to occupy them up vertically (downstairs and upstairs flats), as well as horizontally (across one level) and even as individual rooms. The downstairs flat has a garden, the upstairs one a roof terrace. And as each storey is more than three metres high they can also serve as shops or offices. The blocks are suitable for mixed use and it is this flexibility and interchangeability that is an enduring quality. The buildings’ compact design provides a net density of 85 units per hectare, thus allowing for an outstanding quality of amenities. The Vondel Park and a variety of cultural facilities – the Concertgebouw and several museums – are to be found in the immediate vicinity. However, the street profiles are too confined to be able to absorb the current pressure of parking. Spatially the whole area is contained in a rectangular pattern, which stands in good stead with the spatial structure of the surrounding districts. At the same time the system of urban spaces allows for functions (including traffic) at all planning levels of the city.
Urban areas of this kind can be found in every town or city. They move with the times without exhibiting any major signs of deterioration. It would be an interesting intellectual exercise to see what the effect would have been if the characteristics of districts like these had been applied to the ‘sustainable’ urbanism of the GWL site in Amsterdam and De Wijk in Tilburg. The issue then is about characteristics that relate to an urban programme geared to compactness, a mix of functions and long-term flexibility; about the position of the site within the city (accessibility), the design of the urban floor plan and the relationship with an ever more rapidly changing society.
Central city locations like the GWL site automatically have an urban programme, in terms of both mixes of function and density (100 dwellings per hectare). Moreover the site is easily accessible by public transport and bicycle, and there is no parking problem as only 30% of the inhabitants are car owners. In fact most bought their houses specifically (or partly) because of the district’s relatively car-free status. The only question is whether the urban plan is sufficiently resistant to the changes that time will bring. If we compare the GWL site with other recent inner-city locations, such as Borneo-Sporenburg, Stadstuinen (at Kop van Zuid in Rotterdam) or Groothandelsmarkt (The Hague), we are struck by the fact that all these schemes have a similarly intensive, mixed programme, are easily accessible and, generally speaking, have managed to solve the parking problem by means of multiple space usage.21 Evidently the designers of these areas are sufficiently eco-conscious to devise such solutions.
But the situation is different if we take sites like De Wijk (currently referred to as ‘Vinex development locations’), some 50 of which are being built at present with a capacity for 600,000 dwellings. Quite apart from whether these are suitable sites and programmes that can deal efficiently with the space, there is also the question of whether spatial patterns are being developed that can link up to the existing city plan, are resistant to future changes and respect both the quality of the environment (landscape) and the desired programme. There is a feeling that the designer of the De Wijk master plan has concentrated primarily on the four architecturally unified residential areas imbedded in the landscape. Less attention has been accorded to establishing links with Tilburg’s urban floor plan and to any future transformations which may take place in the planning area.
Sustainability for urban design resides primarily in the urban floor plan and its capacity to accept changes over time (flexibility). These changes relate to the use and structuring of public urban space and the use, building volume and architecture of buildings within that plan. It is important in this respect that the design is not predicated upon simple, time-related considerations, such as the >market-hugging= domestic programming of the Vinex locations. On the environmental front too, simple time-related responses are being trotted out, responses that according to some are resulting in identical urban interventions on almost all housing development sites (closed water cycle, minimum use of hard surfaces, closed ground balance…)20 It is therefore even conceivable that these districts become so inflexible as to endanger sustainability itself.

John Westrik is a senior lecturer in urban design at Delft University of Technology.

3. Definition taken from Dennis Meadows et.al., ‘De grenzen voorbij’ (1992), in Bob Kassenaar, Ideeën voor een duurzame stad, Milieudienst, Amsterdam, 1994.

4. Nota duurzaam bouwen, Ministry of Housing, Spatial Planning and Environment, 1990.

8. For a detailed discussion of the GWL site, see Archis no. 5. 1996; Hans Ibelings and Ton Vestegen, Westerpark. Architectuur in een Amsterdams stadsdeel 1990-1998, NAi Publishers, Rotterdam, 1998.

12. For Wytze Patijn’s observations on the environmental-maximization method, as included in De milieu-maximalisatiemethode, see note 10.

19. For a detailed description of the Borneo-Sporenburg design, see Archis no. 2, 1995.