Since the time of the utopians at the end of the 19th Century, we could say that the urban development world has always shown an interest in the environment, in 'liveable' towns and cities. We have less experience with the concept of sustainability. Awareness of the inevitable need to concern ourselves with this issue is forcing us into a conceptual reappraisal of the products of our profession. This is especially true in physical planning situations, where the interests of existing users, reflected in direct amenities, do not automatically coincide with the interests of future generations: with sustainability.

This is a dilemma that we now face daily, and I would like to discuss it on the basis of professional practice as we experience it in Amsterdam.

You probably know Amsterdam: a typical medium-sized European city of around 720,000 inhabitants, in a region with population of 2 million. Its port is the fifth largest in Western Europe and its airport ranks fourth on the list. Its economy is very diversified and dynamic, and the population, after shrinking in the 1970s, has been growing strongly again since 1985.

Of course, my professional colleagues know Amsterdam mainly for the fact that, ever since the development of the canal rings, urban planning has actually always been a factor in city politics and as such, forms part of Amsterdam's cultural heritage. The General Expansion Plan of 1935 is famous, as it ended two decades of conceptual debate with a plan designed to guide the city's development up to the year 2000.

I mention this, because we can now recognise the conceptual debate as an embryonic discussion of the conflict between amenities and sustainability.

Of course, the Garden City movement also had widespread support in the Netherlands. In Amsterdam, it was mainly the City Housing Department, which saw a future in this utopian and anti-urban picture of society, as a reaction to the abominable living conditions of the 19th Century. The department provided for the expansion of the city by creating garden cities some distance away.

But there were also those who did believe that the city had a future, and who felt that modern urban development in Europe and the US showed that a fairly high standard of amenities could be realised within the boundaries of the city itself. Berlage's 'Plan Zuid' was a showpiece for this school of thought, and it was therefore the city engineers who gave shape to these ideas.

This 'tribal war' was settled in 1928, when the City Council decided to form an Urban Development Department, which was instructed to draw up plans in line with conditions that we would now call the compact urban concept. The arguments put forward in favour of this compact model show a striking similarity to our modern criteria for sustainability.

The courage to opt for sustainability was based on the expectation that modern architecture offered unprecedented prospects for amenities in the direct residential environment. You could say that modern architecture made it possible to think in terms of compact urban models again.

History repeated itself strikingly between 1965 and 1985. In 1966, the Dutch central government published a policy document on physical planning: the Second Physical Planning Paper. This widely- supported plan was based on the idea that cities should not be allowed to continuously expand but, in the wake of the tremendous post-war reconstruction effort, should mainly concentrate on consolidation and improvement: on urban renewal. In other words, a pedigree sustainability principle.

The growing need for space would primarily have to be absorbed in satellite towns around the cities, through so-called 'controlled decentralisation'. Powerful legislative and financial instruments were developed in order to realise this policy, getting both urban renewal and the development of satellite towns off to a flying start.

But from the point of view of sustainability, controlled decentralisation proved to have disastrous effects. Thanks to strong financial stimuli, the satellite towns developed so fast that they began to drain away existing facilities from the central cities. Existing urban structures disintegrated and new ones developed elsewhere. Moreover, since employment did not decentralise spontaneously, there was explosive growth in mobility, with all its devastating consequences: open spaces between the central cities and the surrounding towns fell victim to ever-growing transport infrastructure. And ultimately, because it was the most energetic and dynamic population groups who left the cities first, the first signs of social segregation began to appear.

Between 1965 and 1980, the population of Amsterdam fell from 865,000 to 720,000, while incoming commuting rose from 80,000 to 145,000 between 1970 and 1985 and the quality of the supply of urban facilities declined to a distressingly low level. For these reasons, Amsterdam decided at the end of the 1970s to go against the national physical planning policy. It published a zoning plan that was once again based on the self-serving city. Housing construction was again planned in and on the outskirts of the city, with a strong emphasis on concentration and intensified use of space.

In addition to a number of general goals, the key issue in the 1985 zoning plan was the introduction of the compact city policy. To quote from the plan:

'The "compact city" is a combined concept, which can be translated as a strong city in a concentrated metropolitan region, with the following goals:

This new compact urban policy was strongly promoted on two fronts: in the city's own urban planning policies and in negotiations with central government. The latter was necessary because the entire legislative and financial system was geared to building satellite towns, which represented a handicap in the realisation of urban goals.

This did not stop Amsterdam from putting the policy into practice. Urban renewal continued unabated, but at the same time, additional construction took place in and on the outskirts of the city. In the 1980s, 25,000 homes in the SV district were improved and 20,000 were demolished, for which 12,000 were rebuilt. In addition, 27,000 homes were built within the built-up area and 10,000 were completed in new suburbs.

At the national level, the definite turnaround occurred in 19.., when a new national policy plan for physical planning was adopted, in the Fourth Physical Planning Paper, the VINEX. The basic principles for the physical planning strategy were drawn directly from the compact urban policy, as follows:

'Policy for planning of urban districts is aimed at locating new residential, working and recreational areas and amenities in and as close as possible to large and medium-sized cities. The following local criteria should be applied, as an inter-related set:

Another special point that I should mention is that the VINEX was published in combination with the first national environmental policy plan and the master plan for traffic and transport. This meant that national policy on physical planning, traffic and infrastructure, which until then had been fairly sharply segregated, were co-ordinated and, for the first time, a national environmental policy was formulated as the binding framework.

In a sense, these government papers also represent a contract between central and local government. It was agreed, for example, that 100,000 homes would be built in the Amsterdam region between 1995 and 2005 to absorb the city's growing need for space. The distribution is as follows:

Amsterdam 40,000

Almere 30,000

Haarlemmermeer 15,000

Purmurend 8,000

Zaanstad 7,000

Of the 40,000 homes for Amsterdam itself, 15,000 are to be built on the perimeter of the city, which means 25,000 will have to be built in the city.

More than ten years of compact urban policy has meant a struggle with scarce space. But it has become clear that the issue is not only that of physical space in terms of hectares and square metres, but increasingly, one of the availability of environmental space: space where responsible development is still possible.

During more than a decade of implementing the compact urban policy, we were also aware of what we came to call the 'paradox of the compact city'. In brief, this means that compactness, a condition for sustainability on a macro scale, creates problems for direct amenities on a micro scale.

A problem that came up with increasing frequency was that the mentality and, more importantly, the tools of physical planners and environmental managers do not coincide.

In the Netherlands, physical-planning legislation focuses mainly on procedures: by means of these procedures, efforts are made to reach agreement on the best results for the use and layout of the available space. Environmental legislation, however, is strongly normative. Noise levels of 60 dBA are OK, 69 dBA is permissible and 70 dBA is banned. Emissions of 134 grams/m³ NO2 are all right, but at 136 grams/m³ they become dangerous. And this is regardless of the place, the environment or the circumstances.

New standards are being developed for noxious odours, be we recently discovered that as a result, bakeries would no longer be permitted in residential areas. According to the environmental standards, bread smells bad. One of my colleagues recently commented that if this goes on, we shall be chopping down pine woods near residential areas because they don't comply with the odour standards.

For these reasons, in 1994, we published a policy document on urban planning and the environment, the BROM, together with the Amsterdam Environment Department - in an effort to integrate policies on physical planning, amenities and sustainability. At the moment, this is still an experimental approach, which cannot yet be translated into operational tools. However, we claim the room to experiment with this.

There is a considerable need for such a toolbox. In the past, the legal and administrative instruments of each policy area - the tools - were strictly segregated; urban planning tools for dealing with urban planning problems and environmental tools for environmental problems. Besides, it was often not clear at which stage of the planning or urban development process that various environmental aspects could best be handled.

The BROM is a step towards more `custom' work in Amsterdam's urban planning and environment. This custom work demands greater responsibility on the part of the municipal authority - something which fits in well with the ideas put forward by central government in the new National Environment Plan, which aims to stimulate an innovative approach to area-based environmental planning. The range of existing and new area-based policy tools and strategies indicate that the policy document is only a step in the direction of the proposed planning and environmental policy. In other words, the BROM does not give pat answers to `all your environmental problems', but contains a vision and a number of tools to assist in finding inventive solutions to planning and environmental problems in the compact city. The BROM is just the beginning.

The BROM indicates how the Urban Planning Department and the Environment Department aim to improve the quality of the environment in Amsterdam by means of an integrated area-based policy. Important elements of this new policy include:

- Balancing the benefit of environmental measures against planning requirements

- Enabling the application of area-based environmental standards

- 'Trading' various forms of environmental pollution and compensating for a local increase in pollution at other locations in or outside the city.

The compact city policy will be continued, with the emphasis within the city lying on:

- Concentration and function-mixing at strategic locations

- Controlling the growth of automobile traffic

- Preventing unacceptable situations in terms of environmental hygiene

- Ensuring a good structure of green areas and facilities.

The objective of reducing overall environmental pollution in the city is retained. Although the integrated area-based policy is by no means fully operational, the underlying ideas will determine further developments in urban planning and environmental policy in years to come.

Mrs. Monique de Knegt, who works in my department, will present the policy paper in the `Urban Environment Indicators' workshop; partly and in particular because we hope this congress can help us to make further progress in this area.

On the basis of the workshop themes, I shall attempt to illustrate how we in Amsterdam are trying to put our ambitions into practice. This sometimes involves explicitly formulated goals on amenities and sustainability, but more often it is a question of an intuitive sense of the need. The examples are not complete and certainly not exhaustive, but do give an idea and as such, are representative of what we are trying to do.

One area where this has always existed, by its very nature, is, of course, the historic inner city. The considerable mix of functions has always been one of the city's biggest attractions, and still is today. Unlike in other historically important cities such as Venice, Amsterdam's historic centre is still the economic heart of the entire agglomeration, with 80,000 workers and a similar number of residents. The university and the Stock Exchange are located there, and it is one of the main tourist centres in Europe.

We feel it is of the utmost importance that the mix of functions is retained at this level, because the countless cross-links prove to form an exceptionally productive environment with high value added. However, this calls for policy and steering to ensure that weak functions are not ousted by the strong ones, leading to segregation. Strong and weak also prove to vary quite considerably in nature at times. In the 1970s and 1980s, for example, it was mainly the residential function that was threatened, and policy was then developed to promote inner city living. That policy was so successful, that in recent years the situation has reversed: it is now the much strong residential function that threatens to eject the economic and entertainment functions.

We therefore published a policy plan for the inner city in 1993, based on four main goals which, and I quote, `will make the internal relationships and conflicts within the policy transparent and to seek sustainable development.'

The main target is:

- To reinforce the central position of the city centre and maintain the functional mix.

The other three goals set the limits for this:

- To safeguard the historic value of the city;

- To improve the safety and quality of the living environment, and

- To improve the accessibility.

In the realisation of these targets, the characteristic functional areas of the inner city are distinguished, and a specific development policy is formulated for each one. We therefore have areas where certain emphases in the functional mix are articulated.

I shall give you two examples, one involving an extension location and one an urban redevelopment area.

Sloten

Example of an extension of the city. 5,500 homes, 50% council housing and 50% privately owned. The principle was 80% low-rise, i.e. family homes. The need for intensification led to a density never found before in a low-rise area on this scale, of 56 homes per hectare, or an FSI of 0.5. To ensure that this was nevertheless an attractive area, the City strictly controlled the development, gave the architecture very close consideration and used a special fund to raise the quality of public spaces to the required standard. Planning began in 1984, and construction works in 1990. One of the achievements of which we are very proud is that tram services began when the very first home was completed. Ninety per cent of the area is now complete and it has proved to be in high demand among both residents and fellow-professionals on study trips.

The Eastern Port area

A redevelopment area: 8,000 homes in a decaying port area. Original plan was for 80% council housing and 20% privately owned. The ratio is now 50:50. Density is around 100 homes per hectare, or an FSI of almost 1. The first developments largely involve medium-rise buildings. A plan for 2,300 urban low-rise homes is now ready, with the same density.

Planning began in 1978 and construction in 1988. At present, some 3,000 homes have been completed, mainly in the council housing sector. This proved necessary, because government has to set the quality standard for such a project.

Plans are currently being developed by the City of Amsterdam to build a new residential estate on the IJmeer (which at present is a stretch of water adjacent to Amsterdam Port. This new estate, which will hold some 18,000 homes, has recently been christened 'IJburg'. It will cover about 660 hectares of - as yet - unreclaimed land.

The IJmeer has longstanding, close connections with Amsterdam. Even in the 16th Century, it was a busy waterway. Originally, Amsterdam's only access to the open sea was via the Zuiderzee, known as the IJsselmeer after the construction of the Afsluitdijk in the 1920s.

The development of IJburg will mean the loss of an important shallow water system where a number of rare bird species forage, breed and rest. This loss can be compensated by the construction of marshes beyond the dikes, shallows along the coast of the mainland and, if necessary, along the banks of the new development. These must strengthen the existing ecosystems.

The form of the landscaping in the water is in line with plans to preserve the marshlands, which run from the North to the South of the Netherlands.

Living in a part of a city that borders on such an important nature reserve is enriching, particularly if the city and the natural area are integrated. We assume that urban development and nature conservation need not be contradictory. A recent study of ecological structures in the Amsterdam inner city has shown that some systems are developing very strongly precisely in that area, and the diversity is quite remarkable. We assume that with careful planning of the estate, we should be able to increase the diversity of the natural assets in the area. We will not be able to compensate for all of the existing, valuable but nevertheless fairly limited structure. We are therefore aiming mainly for qualitative compensation by increasing the diversity.

Water is our most important natural resource. For both ecological and recreational reasons, the standards for water quality are higher than in possible in older areas of the city. We therefore assume that both the segregated sewer system and the creation of biological purification systems will lead to an improvement. We then have to deal with a typically Dutch water management issue, as we have to deal with three of four different types of water: the water from the city's port and canals, the relatively clean water of the IJmeer and the water in the estate itself. I shall not bore you with the details of how we do this, as you all know that we can.

It will be clear that we assume sustainable development at every scale lever, with attention focusing mainly on energy supply and energy consumption. We assume a relatively high density of 60 homes per hectare, or an FSI of 0.5. The estate was also designed with a direct metro line to the city centre, so that we can expect an average split of 50% in rush hour movements.

Energy generation in the densest sections is based on combined heat and power generation: the residual heat of the nearby and existing power plant and the existing sewage treatment system is used for urban heating. In the less densely built-up parts, wind and solar energy will provide a welcome supplement.

We think that the natural environment will enable us to create a residential area with unprecedented attractions. We know that this is precisely why we must and want to set the highest standards in terms of sustainable urban development.

Under this heading, I want to discuss two major operations in which we are involved, namely urban redevelopment in the pre-war parts of the city, and plans to take action in the Bijlmermeer district, to give this residential area dating from the 1960s a new future.

Both projects are in fact restoration operations arising from maintenance arrears, in terms of both the physical stocks of buildings and in social structures. This is not very efficient from a human energy or a financial point of view, which is why we want to avoid it in future by taking action before decay sets in.

A recent project in this respect is the redevelopment of the western garden cities. These districts, planned in the General Expansion Plan and built at a rapid rate immediately after the war, have ... inhabitants and a stock consisting almost entirely of council housing. The average floor area per home is 65m² and average home occupation around 2.

The western garden cities, designed by Cor van Eesteren, were a textbook example of New Construction when they were built, their main characteristics being `light, air and space'. They were very much in demand - partly because of the strong social relationships, and they remain so today. But the districts are subject to decay and in recent years there has been considerable population turnover.

What we are now aiming for in the western garden cities is to gradually transform them over the next 10 to 15 years into areas which not only have a past, but most of all, a future - while maintaining their characteristic attractions.

Amsterdam was not built for cars. For generations, goods were transported along the canals. But by the turn of the century, road traffic had increased to such an extent that a number of canals had to be filled in to cope. Since then, traffic has gone on increasing and the problems have multiplied. Filling in yet more canals would irreparably damage the historic fabric of the city. That is why Amsterdam is doing its best to cut back the number of cars in its centre.

Everyone agrees that something must be done about the pollution and the noise cars cause, that the streets must be made safer, that the city must nevertheless remain accessible, and that more attention must be paid to the quality of the city's public open spaces. Amsterdam's Traffic and Street Layout Plan is a valuable tool in achieving these aims. It is one of the main practical outcomes of the referendum that was held on 25 March 1992.

The object of the Traffic and Street Layout Plan is to improve the quality of life in Amsterdam's inner city. Not only in terms of the usual environmental components, but also and above all, in terms of the quality of the city's public open spaces. In addition, the plan aims to improve the inner city facilities for cyclists and pedestrians. Reducing car traffic and the number of cars parked in the centre will do this. However, at the same time it is important that the city centre remains accessible to traffic that is regarded as essential for the city's economy. To some extent, this can be achieved by improving public transport facilities.

If traffic in the centre is to be cut back, it is essential that the city's parking capacity is reduced. However, even a centre with fewer cars just remains accessible to all categories of users. Essential traffic will still have to be able to reach the centre in the future; other traffic will have to make more use of other means of transport, such as public transport and the bicycle.

Essential traffic is generally taken to include business traffic and goods traffic. In fact, once non-essential traffic has been reduced and the flow of traffic in the centre has been redirected, the centre will become more accessible to these groups. However, if the city centre is to continue to fulfil all its functions properly, it is vital for the other user groups that public transport facilities and facilities for cyclists are improved. In view of the space that will be regained in the centre because there are fewer cars, this should not pose a problem.

In the period up to 2005, new infrastructure will substantially improve the accessibility of the centre. The construction of the IJ Road (1998-2005) will provide the centre with a good, fast connection with the Ring Road. By linking the Singelgracht rout (Nassaukade, Stadhouderskade, Mauritskade) with the IJ Road, a ring road giving access to the centre will be created.

Public transport will also be vastly improved by the construction of the IJ high-speed tram line (1998-2005) and the Noord-Zuid metro line (2003-2005).

Improving the tram network is also essential for transporting people who leave their cars in car parks on the city outskirts into the centre and back again. As part of its mobility policy, the City of Amsterdam has designated locations for transfers from private to public transport. Bijlmer station (or the new Zuidoost station), Zeeburg, Buikslotermeerplein, Contactweg (near Sloterdijk) and Riekerpolder have all been designated as transfer locations. These locations are intended above all for people travelling to the centre who can - safely - leave their cars behind and continue their journey by efficient public transport. Each transfer location will hold around 1,000 cars.

Cyclists, too, should benefit from the space that will become available when the number of cars in the centre is reduced. This will provide an excellent opportunity to perfect the cycle route network and to ensure that adequate facilities are provided, so that cyclists can leave their bicycles securely.

Reducing the available parking space and the number of cars on the roads will free public open space in Amsterdam. Various suggestions are made in the Traffic and Street Layout Plan for using this space. These should not be seen as final plans that could the put into effect right away, but rather as illustrations of the possibilities that an inner city with fewer cars could offer in terms of the quality of its open space. Improving the quality of public open space, in terms of both design and use, could have a direct beneficial effect on the investment and business climate in the centre.

Various kinds of open space - parks and gardens, promenades and squares - can be used in various ways: places to play or sit quietly, chat, play chess, knit or simply sit in the sun, a theatre for puppets and clowns, room for a fair or circus, a market, a crafts workshop, a shady lane to walk the dog ... just some of the many possibilities. This is why, when the Traffic and Street Layout Plan is implemented, a great deal of thought will go into the uses of new open space and the form of management and tools that will be required.

This brings me back to the way in which we develop and use our planning instruments. As I already mentioned, Amsterdam has a strong tradition in integrated planning. The General Expansion Plan is well known, but Amsterdam still produces zoning plans. We try to give planning a process character, through continual monitoring on the basis of which periodic zoning plans are drawn up. We link these to political and administrative cycles, with each administration drawing up its own plans for a four-year period.

Because zoning plans must be fairly general in time, we produce annual Physical Planning Investment Programmes. These are implementing programmes in which we compare requirements and (financial) resources, enabling us to propose priorities to the City Executive.

We think that, using these tools, we will be able to make the inter-relationships and consideration of physical planning, environmental policy and economic policy feasible in a transparent way.

However, every zoning plan is a product of its era, and always reflects social priorities. The 1985 plan focused strongly on the switch to the compact city, while the 1990 one concentrated on housing construction. The most recent plan, which we have just drawn up, takes the environment as its guiding principle.

As physical planners, we were trained to divide up scare space in physical terms, expressed in hectares. We have recently discovered that the real shortages increasingly lie in environmental space. In other words, the issue is no longer the surface area to which human activities can be allocated, but far rather, one of which areas are still available where human activities can take place at all, from the point of view of environmental hygiene and of sustainability.

That brings me to the end of my talk. I see I have made considerable demands on your stamina and patience. I hope I have not got too carried away by my enthusiasm. I came here mainly to learn something from this congress. I hope that my 'warm-up' talk also made a small contribution for you.

I want to wish all of us a very instructive congress.