Barbara Franziska Weilenmann
In Switzerland, as elsewhere, over the past decades, urban areas have spread outwards â consuming the surrounding countryside in the process. The result has been an urban growth associated with negative effects such as the loss of cultivated land.
Sprawl is the term often used to describe this process, accentuating the perceived inefficiencies of the undesirable development. A number of hypotheses have been forwarded to explain sprawl, but empirical evidence of factors that influence sprawl per se is limited. The main objective of this thesis it to develop a sound understanding of socio-economic drivers of urban growth and to gain insights into the determinants of spatial patterning of land consumption.
Chapter 2 presents a comprehensive overview on socio-economic factors that shaped urban development processes in Swiss municipalities over three decades. In order to grasp urban sprawl, four different measurements of particular forms of urban growth are considered. The study shows that accessibility, increasing wealth or an aging population have all been important determinants in fostering the extension of urbanised area, altering its densification but also stimulating the dispersion of settlements. Population growth, however, seems to have a less straight forward effect on urban growth than received opinion would suggest.
Chapter 3 focuses on the relationship between tax and urban growth. Following the theory of Tiebout, the analysis engages in how differences in local tax, impact land consumption. The findings show that a municipalityâs low tax scheme either leads to a reduction of per capita land uptake and growth of the settlement area â densification â or to a growth of the per capita land uptake â urban sprawl. The different outcomes â mitigated by the respective accessibility of the municipality â supports that planning policies should be coordinated with other sector policies such as tax or transport infrastructure policies.
Chapter 4 focuses on three subjects: land scarcity, low density settlement structure, and the influence of the inhabitantsâ affluence. The results underline that a limited supply of land for construction reduces the per capita land consumption and the extension of the area, and thus fosters densification. However, in those municipalities accommodating wealthier households, land scarcity has only limited impact on the reduction of land uptake. This might be due to affluent households having an interest in securing a relatively low density structure in their neighbourhoods. This, in turn, raises concerns over equity, and efficiency of policies that limit land for construction. Accordingly, when applying such policies, suitable accompanying measures should be taken.
Why is the question of socio-economic determinants of urban growth important? Managing land development in a sustainable way is a challenging task which requires a certain understanding of causes and consequences of urban growth. As shown in this thesis, socioeconomic factors affect land development in expected ways but might also have unexpected effects, depending on circumstances, geographical scale or spillover effects. With such insights, this thesis hopes to further the understanding of those variations, in order to contribute to a sustainable use of land.
EPFL2019
