Densification of residential areas in the Canton of Geneva (Switzerland): a lever to strengthen ecological connectivity?

Abstract

In Geneva, the low-density housing area occupies nearly 40 % of the canton's building areas, but accommodates only about 12 % of the population. Under the impetus of federal and cantonal public policies, a more rational use of land is recommended. Building areas must therefore be densified to accommodate urban development, thus avoiding encroachment on the agricultural zone. With this in mind, the Canton of Geneva amended its legislation concerning these areas in 2013, allowing significantly higher densities than before. This has allowed an increase in the number of housing units, but often to the detriment of the environmental, ecological and landscape quality of these residential districts, which are often richly wooded. Municipalities have however the possibility of defining a framework for this development by setting out a "strategy for the development of the low-density area" in their municipal master plan. The article illustrates the measures deployed to accommodate urban densification, while not only preserving biological networks, but also reconstituting them where they have disappeared. Within this framework, the densification of the low-density area thus becomes a lever to reconstitute landscape and biological networks where they don’t exist anymore or are threatened by diffuse urbanization.