Almost 200,000 acres of land in the fertile Mezquital Valley are irrigated with the untreated sewage of Mexico City. The project will ask what hydraulic, soil, ecosystem, social, and policy conditions can increase chances for success and what its prospects for socioecological sustainability are.
Montserrat Bonvehi Rosich
Seth Denizen
David Moreno Mateos
Harvard University
Graduate School of Design
© Seth Denizen.
Jury
Scott Duncan
Iker Gil (Chair)
Marina Otero Verzier
Nicola Twilley
Doug Voigt
Charles Waldheim
Almost 200,000 acres of land in the fertile Mezquital Valley are irrigated with the untreated sewage of Mexico City. Rainwater, urban runoff, industrial effluent, and sewage in Mexico City is sent to the Mezquital Valley through a 60-kilometer pipe. Soils in this valley have been continuously irrigated with urban wastewater since 1901, longer than any other soil in the world. The capacity of these soils to produce conditions in which agriculture can be safely practiced and produce healthy crops depends on complex interactions between soil composition, chemistry, ecosystem function, farming practices, public policy, land management, and the urban design of Mexico City’s hydraulic infrastructure. Without this wastewater, the Mezquital Valley would be a desert, as it falls into the UN’s “drylands” climate category, where rates of evapotranspiration exceed precipitation. Currently, more than 40% of the world is classified as “drylands,” making the Mezquital an important case study in wastewater reuse for a warming world. The goal of this research project is to evaluate the successes and failures of the Mezquital Valley as the world’s largest experiment fertilizing agriculture with human wastewater. What hydraulic, soil, ecosystem, social, and policy conditions increase chances for success? What are its prospects for socio-ecological sustainability? In order to address these questions, we will partner with farmers, urban water experts, and soil scientists in order to understand both sides of the wastewater pipe as part of the same agricultural system. This research will produce an advanced studio curriculum at Harvard University on the architecture of postnatural soils.
Marina Otero Verzier, Juror
© Seth Denizen.
The Right to the Sewage Option Studio
Harvard University Graduate School of Design
Department of Landscape Architecture
Fall 2020
Thinking Through Soil Seminar
Harvard University Graduate School of Design
Department of Landscape Architecture
Spring 2020
Bonvehi Rosich, Montserrat,Seth Denizen, and Gary R. Hilderbrand. “Thinking Through Soil,” Book release at Harvard GSD, Gund Hall Frances Loeb Library Lobby, April 24, 2025. Video, 1:37:55.
Denizen, Seth, Vanessa Agard-Jones, Linda F. Chavez Baca, and Catherine Fennell. “Soil, Land, Fill,” Discussion at Columbia University Graduate School of Architecture, Planning and Preservation, October 20, 2022. Video, 1:47:33.
Harvard University Graduate School of Design, “Episode 1: How Designers are Tackling Climate Change with Restoration Ecology, Food Sovereignty, and Sewage.” Design Now, December 1, 2021. Podcast, 26:45.
Denizen, Seth, Vera Candiani, and Dean Chahim. “Returning to the Lacustrine City in La Ciudad de México.“ Princeton-Mellon Forum on the Urban Environment, Princeton University, September 22, 2021. Video, 1:20:08.
Denizen, Seth. “Wastewater Urbanism.” Institute of Landscape and Urban Studies, Network City and Landscape (NSL), ETH Zurich, March 15, 2021.
Bonvehi Rosich, Montserrat and Seth Denizen. “New Visions for Wastewater Equity in The Mezquital Valley.“ Mexican Cities Initiative (MCI) at the Harvard University Graduate School of Design, February 20, 2021.
Bonvehi Rosich, Montserrat and Seth Denizen. “The Right to the Sewage.” ArcDR3 Lecture Series at xLAB, UCLA Department of Architecture and Urban Design, January 29, 2021. Video, 1:18:42.
Denizen, Seth. "Thinking Through Soil: Case Study from the Mezquital Valley." Kiley Fellow Lecture at the Harvard University Graduate School of Design, Cambridge, MA, September 21, 2020. Video, 1:14:58.
Anderson, Alex. “The Right to Sewage: Agriculture, Climate Change, and the Growing Need for Cities to Embrace Wastewater Reuse.“ Harvard University Graduate School of Design, September 2, 2020.
Mezquital Valley Aerial Image. © 2020 Maxar Technologies, Google, CNES / Airbus.
© Seth Denizen.
Montserrat Bonvehi Rosich
Harvard University
Graduate School of Design
Seth Denizen
Harvard University
Graduate School of Design
David Moreno Mateos
Harvard University
Graduate School of Design
is a licensed Spanish architect and urban designer with an interest in living systems, climate, and soils in urban environments. Her ongoing project “The Landscape We Eat” seeks to unfold geomorphological, climatic, and infrastructural relationships in food systems. The work was launched as a performance in CA2M Contemporary Art museum in Madrid, exhibited in Milan’s EXPO 2015, and included different publications such as Food Atlas. She is currently teaching in the Department of Landscape Architecture at the Harvard University Graduate School of Design, where she was named 2017–2018 Daniel Urban Kiley Fellow. Previously she has taught both architecture and landscape architecture at the University of Virginia, as well as architecture and industrial design at Iowa State University and urban design at ETSAB-UPC Barcelona. Her designs, built and unbuilt, have received several awards and have been published in Detail, Plataforma Arquitectura, and Quaderns among others.
is a writer, researcher, and design practitioner trained in landscape architecture and human geography. In 2019 Denizen completed a PhD at the University of California Berkeley in Geography, where his research investigated the vertical geopolitics of urban soil in Mexico City. In addition to his geographical work he has published widely on art and design with the Asia Art Archive, LEAP International Art Magazine of Contemporary China, Volume, and Fulcrum, among others. He is currently a member of the editorial board of Scapegoat Journal: Architecture/Landscape/Political Economy. Collaborations include scientific research on Hong Kong’s urban microbiome, as well as art exhibitions in the Blackwood Gallery (Toronto), The Kunsthal (Netherlands), and Para/Site Art Space (Hong Kong). He currently teaches landscape architecture at the Harvard University Graduate School of Design.
is a restoration ecologist interested in understanding the long-term recovery of ecosystems degraded by human development. He is interested in estimating how long it takes for ecosystems to recover their less resilient attributes, like the interactions among soil organisms and plants. Understanding this will allow for the discovery of tools to increase the currently limited performance of ecosystem restoration, and increase our ecological understanding of landscape architecture. To do so, he investigates how the structure of species interactions and the deriving functionality of recovering ecosystems reassemble over the long term. He works on areas degraded by human activities, agricultural fields, and mines abandoned centuries ago. Some of these field sites are the forests of New England, recovering from European settlement agriculture for about 200 years, and Southwest Greenland, where Norse sites have been recovering from ancient agriculture for more than 650 years. Along with these empirical approaches, he has extensive experience with meta-analysis to find global patterns of ecosystem response to restoration efforts and ecosystem recovery.
