Despite the omnipresence of stream restoration practice in the world today, very few projects are comparable in scope and ambition to the restoration of the Bièvre stream in Paris, France. This thesis explores the extent to which a city fixated for centuries on its domination of nature through architecture and civil engineering is prepared to go to assimilate natural processes into the urban sphere. Through analysis of comparable projects in other cities, the degree to which all urban streams are capable of becoming ecologically-functional will be examined.
The Bièvre’s 36-kilometer course stretches from the southwest of Paris near Satin-Quentin-en Yvelines through numerous towns before disappearing into the urban hydraulic network upon its approach to Paris’s dense urban core. Recent plans to restore the stream and uncover its buried sections outside of the core have lead to current plans to reintroduce the stream within Paris proper. Analysis of the environmental history and recent restoration efforts leading up to current plans helps to understand the motivation for such an ambitious project.
Thesis Supervisor: Anne Whiston Spirn
Title: Professor of Landscape Architecture and Planning
Acknowledgements
Many people contributed to this thesis and the six months of research that lead to its completion. First and foremost, I want to thank my advisor, Anne Whiston Spirn, whose writing and teaching on urban nature and city design were of great influence to my pursuit of this subject. For my research carried out in France, I am grateful for the kindness and generosity of Serge and Hélène Antoine, who graciously welcomed me to the annual reunion of Les Amis de la Bièvre, opening countless doors for my research. In addition, I am thankful for numerous individuals from different agencies and associations and at the Ecole national des ponts et chaussées. Among them, Nathalie Roseau, Bruno Tassin, Gilles Hubert, Marc-Amboise Rendu, Pierre-Marie Tricaud, Georges Farhat, Alain Cadiou, and Thierry Maytraud provided me with valuable feedback and insight. Lastly, I want to thank François Meyer for his indelible patience, support, and encouragement.
Introduction
Efforts to restore natural elements in urban environments are increasingly abundant throughout the world, but not all seek to incorporate the ecological functions of the land forms that they are attempting to restore. Diverting storm water runoff or water features from a newly created park directly into the sewer system when that water might be used to irrigate plants or recharge ground water is one example of a lack of attention to the ecological functions of the hydrological cycle. In this thesis, I will argue that the successful restoration of an urban stream should involve the integration of its potential ecological functions, not merely the improvement of its appearance. By analyzing several urban stream restoration projects that have integrated ecological functions, I will identify the measures and means for success which can be applied to all stream restoration projects, particularly the restoration of the Bièvre.
The Bièvre is a 36-kilometer stream that meanders from the southwest of Paris through numerous towns before its bed becomes buried and flow diverted outside Paris’s dense urban core. The environmental history of the Bièvre illuminates the perpetual exploitation and gradual destruction of the stream’s ecological functions over two millennia. Repeatedly drained, polluted, diverted and channelized, segments of the Bièvre’s course, including its entire Parisian stretch, were finally buried around the turn of the twentieth century. Efforts to restore the Bièvre in the 1960s began with a campaign to conserve the stream's exurban source in the Bièvre Valley watershed. The Friends of the Bièvre Valley was formed in 1962 to protect the valley of the Bièvre from development. Since 1981, their sponsorship of an annual walk, which attracts thousands of participants each year, has been a highly successful part of their campaign in raising awareness for the stream. As restoration efforts and awareness have increased, the water quality of the Bièvre has been improved, and its banks reanimated with recreational fishing and leisure activities. Attention to some ecological functions has become a focal point for several projects carried out in the last few years.
The current plans to uncover and rejuvenate portions of the Bièvre
in Paris are the most recent focus in the stream restoration effort. In the
design phase for three years, these plans have evolved considerably in terms
of the amount of attention paid to incorporating ecological functions. Initially
deemed impossible in such a densely developed setting, recreating a naturalized
streambed to allow the Bièvre to carry out its hydrological cycle and
provide habitat for fish and wildlife is now considered feasible by some.
This thesis will compare the different plans for stream restoration of the Bièvre inside Paris and examine the feasibility of integrating ecological functions in this highly urbanized context. This will demonstrate the extent to which all urban stream restorations are capable of incorporating some degree of ecological functions. In addition, it will reveal what elements other than technical feasibility are fundamental to seeing such projects through to completion.
Note on Nature
The subject of this thesis has required me to reflect on different ways in which the word nature is defined. As my personal definition of nature and those of the numerous institutions presented in this thesis are pertinent to my approach to the Bièvre’s restoration, I would like to be explicit about what the word nature means to me.
Defining nature is not a simple task. When asked to define the word for the first time last September on the first day of a seminar at MIT titled "Urban Nature and City Design," I gave the following definition: Nature is everything that does not depend on the presence of human kind in order to exist. While this definition did not include humans and their material creations, I soon learned that many people did count the human world as part of nature. In reflecting on this, I realized that I do acknowledge that humans as creatures are part of the universe and have evolved to their current state, just like all other species on the planet that I do consider part of nature. This obviously conflicted with my personal definition of nature, possibly due to my conditioning to deny humans’ inclusion in the theory of evolution through my Catholic upbringing. To resolve this, another word to describe the universe without human existence may be necessary. Until I find that word, I will continue referring to nature as the physical world without humans for one main reason: my desire to treat humans separately.
Ultimately, my need to separate humans and their influence
from the rest of the physical world is important to the project discussed in
this thesis. All living organisms exploit their surroundings for self-benefit.
Humans do not do any different, but their ability to have greater influence
on the universe makes me want to consider their existence and influence separately.
Throughout this thesis, I used the words ecological functions, nature and natural
interchangeably to describe processes that occur without the presence of humankind.
I used them not so much because humans are less a part of the universe than
other species are, but because they are more disruptive than any other species.
Aiming to minimize human impact on the universe has always been one of my priorities;
and thus identifying that impact and separating it from nature is necessary.
The words nature and natural have different meanings to different people.
One major difference is in the inclusion or exclusion of human kind and the
material things it creates. For the purposes of this thesis, nature will be
addressed as the phenomena of the physical world collectively, minus the presence
of human kind. This definition responds to my purpose of acknowledging human
kind’s ubiquitous influence on the physical world. In the interest of sponsoring
greater appreciation of the natural world, this thesis explores one way in which
humans can minimize their impact on other species and the landforms they inhabit.