White/acoustic infrastructure: a crucial tool for the transition to an environmentally sustainable future in urban areas: The case of Paris La Defense, a modern district in dissonance

Sara El Samman

The national lockdown due to COVID-19 abruptly cut down on human activity in cities, and enabled urban dwellers to notice nature’s comeback through birdsong: It has shown that today’s urban environment is in acoustic imbalance. My research aims to provide an overview on how soundscapes fit into the landscape design process, and to explore the notion of white/sonic infrastructure in order to give a tangible tool for landscape architects to read landscapes with their ears and design acoustically sensible places for all living beings. Sound informs the design process not simply by reducing unwanted noise but by encouraging a sound-considered city design approach. This adopted strategy would entail the extraction and reinterpretation of sonic cues as blueprints for the reshaping of the space and the transformation of the soundscape experience for users and nature alike. The paper applies all of its findings on Paris La Defense, the biggest business district in Europe, who’s current morphology, within the ring of noise that is the “Boulevard circulaire”, dissociates it from its territory creating acoustic and physical discontinuities. A study of the flows that animate the site along with its morphology helped me extract the multiple sonotopes (sonic biotopes) that shape the acoustic space of the district. Sound maps were created and a white infrastructure strategy was furthermore developed. The article develops an elaborate method that could help translate a soundscape vision into concrete landscape design actions and proposes an approach to sonic continuities on large and local scales. White infrastructure affords the additional dimension necessary to conceive the landscape and to create space for the non-human, for the human, and for the dialogue between them. The notion of eco-acoustic design contributes to shaping a non-anthropocentric city that is considerate of all living things and therefore is crucial to designing ecological urban ecosystems.

Acoustic infrastructure puts in relation the process of designing the landscape with the act of composing the soundscape. The notion of infrastructure allows for sound to be perceived as a physical component of the ecosystem and to therefore become a more attainable and tangible tool for designers.

The notion of an acoustic framework to qualify noise in the landscape has only recently started to gain momentum. Romain Sordello, an engineer and biodiversity expert, introduces the notion of "la trame sonore", the sound infrastructure, in his article Trame verte, trame bleue et toutes ces autres trames dont il faudrait aussi se préoccuper (2017) to talk about the relationship of the soundscape on the quality of the green and blue infrastructures. He explains that a network of noise generates habitat fragmentation in the form of landscape degradation.

With the aim to integrate this immaterial and invisible framework within the visual world of design, the terminology of "white" is granted to it. The idea of attributing the color "white" to acoustic infrastructure is interesting: It harkens back to the idea of white noise, a term that designates the sound resulting in the random superposition of all the sound frequencies audible by man (between 20hz and (between 20hz and 20000hz-20khz). Although “colorless”, white is in reality the utmost multi-colored light and reflects well the veracity of sound.

The concept of a white infrastructure (la trame blanche) is mentioned in the Institute of Ecology and Environment of Paris (iEES), which defines it as a framework "formed by silent ecological continuities", a tool to fight against noise that fragments nature in the city. I propose to complete the definition as follows: white or acoustic infrastructure is a natural infrastructure that contributes to ecological continuity. It is composed of areas that are not affected by noise pollution where all living beings, humans and non-humans, can communicate easily and coexist in acoustic balance (El Samman, 2021).

I approach this infrastructure, like any other ecological infrastructure, by talking about centralities of acoustic comfort, where the soundscape is inviting for the fauna and flora to exist peacefully, and about flows of acoustic continuity, highlighting the role of sound as a tool for tracking and navigating within the landscape.

In order to explore the notion of acoustic infrastructure, as a landscape architect, it is necessary to understand what makes up a soundscape. As clarified beforehand in the article, soundscapes are the result of the interactions that animate the landscape, in relation to its morphology, its materiality as well as the climatic characteristics and the evolution of the site over time. Knowing that these elements are what constitute landscape architects’ working palettes, the latter represents the tools used to compose the acoustic space. The landscape architect's role as a mediator between the ecological, social, economical, and physical flows that constitute the non built environment makes him ultimately a main conductor of the city’s orchestra. These themes are what defines the dynamics within an ecosystem. Hence, it is at this scale and through these approaches that sonic notions can be integrated in the design process. It is the keystone landscape actions that, once approached with a sonic lens and an open ear, allow for landscape architects to design soundscapes; where the understanding of the latter guides decisions and choices.

Furthermore, sound exists in synergy with all the other components that make up an ecosystem. Thus, white infrastructure does not exist in vacuum and must be studied in relation to all the layers of the landscape. R. Murray Schafer coined the term “sonotope” to describe a sonic biotope (1993). A sonotope represents the soundscape resulting from a site’s particular characteristics and the whole ecosystem of sounds that interacts with it. This notion allows for a better characterisation of soundscapes as composed environments with personalized sonic events and effects. By identifying sonotopes and understanding the landscape typologies that come with it, landscape architects can extract concrete methods to composing the acoustic space.

Following this line of thinking, the upcoming part of the article develops a strategy to integrate the white infrastructure in the design thinking process, where i’ll go back to La Defense to illustrate my concluded vision on acoustic urbanism.

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