8. Criteria for sustainability

As explained above, from the analysis of what is being done on this topic in the autonomous regions (and also what is not being done) in terms of legislation as well as with recommendations and manuals, the reports by external experts and the assessment of the working group itself, we can identify certain factors that should be considered in order to achieve more sustainable planning and about which there is a fairly broad consensus —regardless of the legal obligations and effects derived from legislation and sector environmental planning. Some of these factors have been set out above (e.g. public participation), but others can be turned into criteria or recommendations to be included in the corresponding regulations. These criteria or recommendations should be assessed by means of indicators adapted to the specific case of each territory, and established and agreed by means of a participatory process in which not only technicians are involved but society as a whole. Examples of these indicators can already be found in some autonomous regions.

Several of the sustainability criteria that should be considered in urban planning are more territorial in nature, but the proposal of the new plan as an intermediate system means that we must take them into consideration even though this report focuses on urban planning:

• Reorganisation of agricultural uses. Highly profitable agricultural land cannot continue to be devoted to urban development, and nor can hectares of non-irrigated land be converted into irrigated land by exhausting underground aquifers, often with disastrous consequences (e.g. for wetlands).
• Strengthening nearby peri-urban farming. Most traditional farming areas around Spain's major cities are disappearing, awaiting requalification to turn the farmland into urban land, and thereby giving it a speculative value that pushes aside its value for use as farmland.
• In some cases a return to traditional grazing should be made feasible. Spain's dehesas are a well-known example —semi-cleared woodland forming a natural anthropic ecosystem that has considerable advantages from the viewpoint of the sustainability of the territory.
• It is essential to reorganise the systems for distributing and marketing farming and livestock products, particularly the wholesale sector, with a view to avoiding as much as possible the inefficiency results from the long journeys of many products. This reorganisation could be strengthened by charging an ecological tax in proportion to the number of kilometres travelled by the product until it reaches the corresponding retail outlets.
• Converting degraded farming areas into forested areas. All land that has been abandoned for farming and livestock purpose because of its greater productivity usually ends up as scrubland and, depending on the circumstances, is highly prone to erosion, ultimately resulting in desertification. If to all this land we add the land that is uncultivated or has no plant cover, we can understand the need for reforestation. This is why some of the government and EU subsidies for uncompetitive farming should begin to be diverted to creating and maintaining forested areas setting up forested areas, which would also allow surplus farm labour to be relocated.
• Hinder use of the territory for tourism based on consuming the territory. Of the many kinds of tourism that may be found in today's society, the most difficult to manage are those that are based on contact with nature with certain non-anthropic values, especially because it is essential to maintain those values to make it sustainable. In general, the carrying capacity of the territory for a use of this type is very low, and nature tourism should never be the economic base of a region, but rather function as additional income. This can be achieved in many ways, but the simplest is by controlling access. Improved communications or accommodation capacity is not always beneficial for maintenance over time. In this regard, certain autonomous regions are making considerable progress in this regard, particularly the Canary and Balearic Islands.

Another set of criteria can be grouped by having a more urban nature, and they should form the central core of the city's strategic plan. Only those about which there is a true consensus in the doctrine, legislation or reports by the experts consulted have been included here.

• Significantly reduce land consumption. Several papers have reported on the growing consumption of urban land per inhabitant. This increase does not only occur because of an increase in the built area devoted to building housing or shops. It basically occurs because of the increase in the developed area necessary to provide these homes with services, particularly communications infrastructures and facilities for free time in the countryside. In general, we may say that part of the cause lies in the fact that most of the facilities and infrastructures are over-sized and poorly located. If we except the case of green areas, which is a special one (also dealt with in this report), a significant number of facilities must meet a set of conditions that are almost never considered: minimal, small, multipurpose, managed by the local people themselves and distributed throughout the urban fabric. And with regard to infrastructures: priority for collective transport with lanes for exclusive use and a combined high-speed/few-stops and low-speed/many-stops system; design of the road network for private transport based on off-peak times and never peak times; use of the subsoil of the city in case it is compact enough.
• Avoid sprawl. The current urban layout, based on the city sprawling over the territory and only possible because of private vehicles, is disastrous from the point of view of rationality. Long journeys (in kilometres but not necessarily in time) between home and work, shops and leisure venues, cannot be covered on foot or by bicycle, resulting in higher energy consumption, higher pollution, the use of more land and greater social and spatial segregation. To achieve this it appears to be necessary to change our planning, as explained above: a framework plan, a cross between spatial and urban planning, that allows clear, lasting limitations to be imposed and specifies land from land, but in a way that is more streamlined and less permanent than current spatial planning. This would lead to far more executive development planning, requiring ongoing knowledge of the environment and its evolution via a set of indicators agreed by the public and a permanent observatory.
• Complexify developed areas. It is now over 30 years since Christopher Alexander wrote a paper titled «A City is Not a Tree». His hypothesis referred to the branching organisation of cities that has traditionally been proposed by urban planners: a city with a hierarchical structure based on a strict separation of uses and made up of a cascading succession of centres and sub-centres that are responsible for distributing facilities, infrastructures and amenities symmetrically throughout the city. Opposed to this is the traditional organisation of the historical city, semi-reticulated, where each component could depend on several sets or subsets at once, giving rise to a much more flexible and efficient structure. Achieving complex cities with the current system of standards is difficult but it could be attempted by increasing both the number of interactions and the variety of the components. This is virtually impossible to achieve in a fragmented city. It could be claimed that if the entire urban area is considered as a whole then there is sufficient variety; it is simply a question of scale. Different facilities, different social classes and different types of housing can always be found within six, fifteen or twenty kilometres. This would be true if there were spaces for interaction that allowed the different to mix. But even in this case the simple costs of mobility in terms of the consumption of land and energy and increase in pollution are unsustainable.
• Control standards and densities. One of the most firmly rooted traditions in planning is that of standards. Throughout the history of urban development and planning a corpus has been built up that basically attempts to limit congestion and the voracity of developers attempting at any cost to grab hold of collective spaces. But we have arrived at a point where fixing only one limit (indiscriminately, too, rather than on a case-by-case basis) has perverted and exhausted resources, resulting in the inappropriate sizing and lack of use of spaces and infrastructures. The same thing occurs with densities. However, a number of plans or land laws are now in place in some autonomous regions that include maximum and minimum densities, making it possible for basic collective-transport infrastructures to be feasible, for example, or allowing amenities that are used sufficiently to be installed. It is essential for services and infrastructures to be sized for people to develop their capacities but also not to waste land or resources in doing so. Therefore, in most cases it will be necessary for standards and densities to have a range of values rather than only a minimum, as has been the case until now.
• Regenerate. Making maximum use of the existing city must be a priority goal. It is often alleged that the costs of regeneration are always higher than those of new building, but that is only because people fail to take into account higher fuel costs, greater pollution or the creation of new social networks derived from a larger developed area. To make optimal use of the existing city it is usually essential to adapt it to improve its habitability conditions. And this adaptation must meet a new requirement that was not essential the last time we returned to the traditional city, in the 1970s: efficiency. In other words, buildings must of course be regenerated with effectiveness criteria (they must make it possible to lead a high-quality modern life), but they must also do so efficiently, by doing it with as little energy consumption and pollution as possible. If we wish to have more competitive cities this requirement is an essential one. Something that was not so clear back in the 1970s when people returned to the city centres has now become crucial. We can no longer regenerate like we did before, merely with criteria of effectiveness (and in many cases arguable ones at that) that must be accepted as given, because otherwise efficiency is impossible, but imposing regeneration with sustainability criteria, which are not only criteria for improving the local environment but are also ecological-footprint criteria, i.e. related to maintaining the planet. It is also necessary to increase the quality of the urban environment. We would be wrong to assume that adapting a home or office building to the times ends at the front door. The urban environment is increasingly seen as being a prolongation of private inhabited space. However, the concept of public space is changing very quickly, and it is very difficult to generalise about it. Perhaps all we can say about an issue such as this is that the most relevant concerns about public space are now related to public security. Addressing this problem is also necessary in order to achieve more sustainable cities and planning should include criteria of this type. In short: ecological regeneration of buildings and public space.
• Renovate parts of the city. In some cases regeneration is probably not the most appropriate solution. In certain buildings (including entire urban pieces) the best solution would be to demolish and rebuild. This may be the case, for example, with tower blocks built in outlying areas when it was necessary to house in cities thousands of immigrants arriving from other smaller towns or villages, where it is very difficult to meet the minimum levels necessary for the objectives of decent housing. Even so, we are talking here about consolidated, fully anthropised urban land, where the costs of returning it to the natural environment are generally greater than the benefits. In these cases all that can be done is to demolish and rebuild with sustainability criteria. As with regeneration, this involves a number of difficult operations where there is always he danger of regeneration actually meaning replacing complex social bodies with other equal ones, generally corresponding to social layers with more disposable income. Implementing an urban renewal or regeneration project properly calls for extreme care by planners and it would be an error to leave its management solely in the hands of builders or developers.
• Give priority to rented housing. The problem, which has been reported many times by different authors, is that much of Spain's savings are invested in real state products, leading part of the housing stock to be made up of unoccupied, locked-up homes. Putting many of these houses on the market, if possible for rent, would relieve the pressure on major sectors of territory that are currently being eyed by builders and developers. The authorities now seem to be moving forward in this respect, having tried unsuccessfully to lower housing prices while the 1998 Act was in effect, by increasing the amount of land classified as developable. However, the evolution of types of occupation would seem to allow us to be optimistic. If in 1970 rented housing accounted for 30% of the 8,504,326 homes in the census, in 1981 it was only 20.8% of the stock of 10,430,895, and in 1991 only 15.2% of a total of 11,736,376. The need to increase the amount of rented housing is a basic one from a sustainable viewpoint, not only to make optimal use of all urban areas but also because of the problems of territorial fixing that are caused by home ownership. The discrepancy between mobility at work and residential immobility inevitably results in an increase in travel, much of it in private vehicles, as many studies have confirmed.
• Design with bioclimatic criteria. This is a very important criterion for achieving more efficient cities, not only because the planet cannot withstand the constant waste of resources, but also because it has been shown that human beings respond better to built elements that are in accordance with the environment where they are located than to ones that stand out from that environment. And, of course, also for simple criteria of urban hygiene that have been proven and put into practice in answer to the problems created by the cities of the Industrial Revolution. This demand can already be seen on both a national and regional scale, and even locally, as we can see from the approval of the Technical Building Code or Bioclimatic Bylaws by various local authorities in Spain. However, it would appear to be necessary for certain autonomous regions to act more firmly, as they are tending to fall behind on this issue. It is also the case that bioclimatic design should be applied not only to buildings but also to urban spaces. In the design of pavements, squares or green areas environmental considerations are key to achieving more sustainable cities. In particular, in the case of green areas, their consideration as landscaped areas requiring constant regular care, the use of fertilisers, catering, pruning and pest-control systems should be reduced to the essentials minimum. Besides considerations of strict sustainability and the defence of the natural environment we must add maintenance costs, and rationality must prevail. It would seem to be necessary for this way of viewing green areas to be replaced with one that has more in common with forestry and self-maintenance criteria (as indeed some local authorities are doing).