The Ecocentury Project

Composite Landscapes in Luxembourg.
Research project funded by Fondation Braillard Architectes, Geneva, 2017-2019.

The Programme in Architecture, European Urbanization and Globalization, participates in the "The Eco-Century Project: Architecture, Planning and Landscape under the Prism of our Planet’s Resources", launched by Fondation Braillard Architectes. It is an interdisciplinary Programme fostering innovative research and ideas on the connections between forms, functions and values of our built environment with regard to the ecological transition.

Within this framework, the Composite Metabolic Landscapes in the Luxembourg Region research proposal aims to explore alternative spatial development trajectories, responding to the intensive population and economic growth patterns of the Luxembourg region, and its largely unsustainable – both socially and ecologically - spatial development condition. The goal is to define a development envelope, or better a composite development gradient, that will be able to accommodate a more than 50% increase in population over the next 20 years, and an overall population of one million in the year 2060 in the state of Luxembourg.

Luxembourg has been experiencing rapid economic growth, showcasing continuously one of the highest GDP per capita in the world. Annual economic growth rates in the range of 2-5% have been accompanied by a cumulative increase in population of more than 40% since the 2000, and a more than 250% growth in the number of trans-border commuters. Although these trends are imposing huge pressures upon the landscape, agricultural and forested areas still occupy more than 85% of the total area of the country, with no more than 10% covered by settlements and no more than 5% by infrastructural networks.

An extensive assemblage of small and medium sized towns, compile a cross-border commuter belt around the city of Luxembourg. Only when the daily operational pattern of this extensive commuting network is taken into consideration, are the true dimensions of the urban system revealed, with Luxembourg city as its economic engine. With a population of around 600 thousand, Luxembourg is the commuting hub for more than 250 thousand daily commuters, leading to an almost 50% increase of the ambient population during any weekday.

The very uneven pattern of economic development, is interwoven with an equally problematic ecological performance. With close to 40 tonnes of carbon footprint emissions per person (due to the particular commuting pattern), Luxembourg is at the top of several lists trying to grasp environmental impact in terms of CO2 emissions. At the same time, the narrow interpretation of landscape dynamics, amplifies social and ecological problems: With forested and agricultural land excluded from development trajectories, Luxembourg is struggling to accommodate its annual economic growth without developing land at a similar pace. Increasing real estate prices, combined with the vision of conserving the ‘natural’ landscape, are directly interconnected with the highly problematic ecological performance of the region:

The less land can be developed within Luxembourg, the more expansive the commuting belt becomes, leading to a series of negative externalities, both social (increased cost of living, congestion), and ecological (CO2 emissions, energy consumption, pollution). Luxembourg is revealed as both an economic engine and an entropic black hole, tied to a paradoxical condition in which the more ‘green’ its landscape tries to be, the more it is offsetting social and ecological costs beyond its boundaries.

The project aims to develop a thorough investigation of the landscape typologies of the urbanization fabric in Luxembourg, building upon the construction of a detailed geospatial basis, and through this detailed portrait explore the potential modes of densification. The scope is threefold: Offer a system of alternative mappings of the urbanization fabric revealing the typomorphological qualities of the built environment; develop a composite classification of the optimal locations for development based on a combination of social and spatial criteria; develop alternative scenarios for densification of the built environment. The project approach is driven by a strong emphasis in integrating geospatial modeling into the investigation of modes of urban development, and models of urban design.

As a result the project starts with a construction of a detailed, coherent, homogenized and refined geospatial basis, with an emphasis on revealing the qualities at the scale of buildings, parcels and blocks. The first stage of the project, consists of an exhaustive survey of available data, but also construction of necessary datasets at the scale of the building. While data on the footprint of buildings and parcels are available, there is no available information on building heights, and the detailed distribution of population, so even simple but core metrics (such as building coverage indicators or detailed population density indicators) cannot be explored. Thus, the first stage of the project, aimed to create the necessary data at the building and parcel level, based on a combination of remote sensing (use of LIDAR data to calculate building heights) and a disaggregation of census data available only at the commune level. The result has been a very detailed population by building map of the whole country, building massing, and core parcel statistics. The creation of this detailed basis has been central for the investigation of the typomorphological characteristics of the built fabric in the next steps.

The second stage of the research dealt with the construction of a development classification index of the whole territory of Luxembourg, according to the optimal areas for predominantly housing development. The process builds upon the detailed geospatial data constructed in the previous step, and developes a series of studies around crucial indicators for the development of sustainable urban fabrics. The definition of the indicators follows a review of major literature on sustainable development, highlighting four major requirements: First, high compactness of the built fabric, translated to metrics regarding the distances between buildings, distances between buildings and road networks or the edges of blocks, size and coverage of parcels. Second, high density, translated to metrics of floor to area ratios and population density. Third, high degrees of non-car accessibility (walk, public transport) to everyday functions (education, retail, places of work), translated to a series of accessibility maps. Fourth, mixed use, translated to an investigation of the mixture of functions. The project utilizes a Multi Criteria Evaluation analysis (MCEA) methodology in order to combine the different criteria into classes of optimal and less optimal development. MCEA is a powerful and popular methodology for combining different indicators towards certain goals, which however are subjectively defined through the intentions of the researcher. In our case, the intention was the development of “infill” development, trying to identify areas that are densifying the existing fabric (rather than adding new), developing along existing infrastructures (rather than adding new) and have high degrees of accessibility and functional diversity. A series of additional constraints were added to the MCEA model, such as distance from protected areas, certain types of infrastructures and land uses (mines, highways, dumpsites etc). The classification index developed on a grid was then associated with the particular parcels of land, and classified them according to their potential for further development, taking into consideration existing, already built areas.

The third stage of the research regards the definition of a set of alternative forms of classification of the urbanization fabric in Luxembourg, and especially the built fabric, that will allow its typomorphological classification. The configuration of the physical elements of the urban fabric (buildings, roads, parcels, blocks, open spaces), with their own functional dynamics, produces different “drawings” in cities. By disaggregating the urban texture into different components, it is possible to study the topological, geometrical and dimensional relationships between the elements and go beyond the description of the urban fabric through the typical figure ground map, developing more detailed categorizations of the qualities of the urbanization fabric. In this effort, the project explores through the relevant literature a series of indicators, besides the typical floor to area ratio and building cover ratio: Variance, aiming to reflect the variance in the composition of shapes in the landscape; fragmentation, aiming to reveal how fragmented a built landscape is; compactness aiming to reveal how compact the configuration of buildings is; and indicators showing the nearness of building s from streets and each other. The aim is to combine these indicators into groups of identical and characteristic fabrics, identifying where they are similar through a standard multivariate cluster analysis methodology.

Finally, the last and most speculative step of the research is building upon the previous to, in order to suggest alternative scenarios for densification: Having the areas defined by the development classification index, and the types of urban fabrics defined by the cluster analysis, the project will explore the transformation of existing landscapes, or the introduction of new ones, in order to propose new types of densification (rather than deal with particular sites).