Researchers from various fields are already investigating how to deal with the phenomenon of shrinking cities. We believe that landscape architects can deliver a great contribution in these investigations, since the developments in shrinking cities are no longer determined by the constructed areas but by the open spaces in the city.
For decades, city shrinkage has been an ongoing problem in the Netherlands. This decrease in population numbers is mainly caused by migration. The latest literature on city shrinkage claims that a flexible strategy is needed that can deal with the uncertainties that shrinkage brings. The ‘casco approach’, developed by Kerkstra and Vrijlandt in 1988, is an interesting strategy in the field of landscape architecture that deals with the uncertainties of future developments. The approach proposes to separate the landscape into a stable framework for low dynamic functions and flexible pockets for high dynamic functions. In this thesis, we formulated the hypothesis that the casco approach can be a basis for the development of shrinking cities in the Netherlands since we suspect that it can react on the uncertain developments of shrinking cities through the flexibility of the high dynamic pockets and that it can strengthen the special qualities of a city in the low dynamic framework, which could otherwise be negatively affected by shrinkage. To test the hypothesis we formulated the main research question as follows: In what way can the casco approach form a basis for the development of shrinking cities in the Netherlands?
To answer this question we used the casco approach in two ways. Firstly, we researched city shrinkage through the perspective of the casco approach. We investigated the low and high dynamic elements of shrinking cities in the Netherlands through a literature study, interviews and map analyses of the Dutch shrinking cities Delfzijl, Den Helder and Heerlen. Secondly, we developed a strategy for Dutch shrinking cities on the basis of the casco approach. Based on this strategy we produced a design for Den Helder. On the one hand we used this design to explain the theory and on the other hand we used this design to test the theory, or in other words to do research through design.
The research into the low dynamics of Dutch shrinking cities demonstrates that important networks preserve their function and that special buildings and landscapes preserve their form over a long period of time. Furthermore, we noticed an opportunity for the low dynamic framework in shrinking cities: the freed spaces in shrinking cities could be utilised for expanding the green networks of the city. In researching the high dynamics we investigated the social and the spatial dynamics in Dutch shrinking cities. From this research we can gather that the demand for, among others, houses and certain facilities decreases. This leads to vacant and derelict buildings and vacant lands scattered over the city, which affects the appearance of the city. Consequently, a downward spiral could start; more inhabitants leave, which leads to a further decrease of the appearance of the city. Next to these well-known consequences of shrinkage, we noticed some remarkable developments in Dutch shrinking cities. One of them is the construction of new residential and business areas as expansions of the city. These expansions are in conflict with the declining demand for these functions and worsen the oversupply of buildings. Another remarkable development is the high number of additions and removals of infrastructure. A lot of money could be saved if the developments in shrinking cities are geared to the existing infrastructure. Besides this, we also noticed an opportunity in shrinking cities for the high dynamic pockets: the high number of private initiatives can be very interesting to develop in these pockets.
After we distinguished the low and high dynamics of shrinking cities, we compared these with the low dynamic framework and high dynamic pockets of the casco approach. On the basis of this comparison we concluded that the casco approach is, to a large extent, a useful basis for the development of shrinking cities in the Netherlands. We determined that some aspects of the approach are appropriate to apply with shrinkage and that other aspects should be revised. With that in mind we started to renew the casco approach to make it more suitable for shrinking cities.
The basic principle of the renewed casco approach is similar to the casco approach of Kerkstra and Vrijlandt, which is to divide the landscape on the basis of dynamics into a stable framework and flexible pockets. The framework has three goals. First of all, it has to preserve buildings and landscapes that add to the distinctive quality of the city from degeneration and removal. The second goal is to use the elements that are essential for the optimal functionality of the city, so that the amount of unnecessary investments can decrease. Finally, the framework should utilise the opportunity of city shrinkage to extend the green networks of the city. The spaces that are not included in the framework are the pockets. Here the city can respond to the uncertain developments of shrinkage and in such pockets space is available for the development of all sorts of initiatives. We set up some restrictions and spatial guidelines concerning the freedom of the pockets to combat a surplus of dwellings and facilities, to gain control over the limited developments in shrinking cities and to counter the degenerated image of shrinking cities.
After extensive research, we can conclude that our renewed casco approach seems to be a suitable approach to work with shrinkage in Dutch cities. The new strategy that we provide for shrinking cities could trigger the discussion about how to work with city shrinkage. Next to that, the renewed casco approach could perhaps, after some further research, be executed in a shrinking city to test the theory in practise.