Chiara Geroldi is an architect and researcher, currently Assistant Professor of Landscape Architecture at the Politecnico di Milano, DAStU Dept. She holds a PhD in Environmental and Territorial Safety and Control (2015), jointly awarded by the Politecnico di Milano, Torino, and Bari (Scuola Interpolitecnica di Dottorato), and developed part of her doctoral research at the Harvard University Graduate School of Design as a visiting ‘special student’. Her work focuses on the design of landscapes formed by discarded earthy fill, as well as energy landscapes and brownfield regeneration. She is the author of Moved Earth: Designing Landscapes with Discarded Fill (Routledge, 2026) and co-editor of Ecologies of Desealing and Open Ground (both Mimesis, 2025). In this interview, we discuss her new book, Moved Earth and the role of landscape architecture in shaping landscapes built from large quantities of discarded soil.

Zaš Brezar: Your book Moved Earth: Designing Landscapes with Discarded Fill is just coming out. Please tell us more about it and what landscape architects can learn from it?

Chiara Geroldi: My main interest is to understand what contribution landscape architecture can bring to technical fields that are usually addressed by other disciplines. I am interested in how designers can contribute to constructing more significant landscapes by providing their expertise within collaborative environments, in fields that are typically the prerogative of other experts, such as engineers or technicians.

The book is focused on the use and design of large amounts of discarded fill in landscape design projects. By ‘discarded fill’ I mean materials that can be as diverse as tunnel spoil, dredged material, mining waste, or construction debris. I focus on some of these categories, and I deliberately use a broad term—fill, which is similar to made ground—in order to embrace the complexity and the wide range of situations encountered when dealing with discarded material.

Despite the diversity of materials that can compose the made ground and the fact that each has its own specificity and meaning, I argue that there is a family of landscapes that share similarities and can be interpreted as a category. This is what I call “designed landscapes of discarded fill.” A heap of garbage transformed into a park shares certain similarities with a heap of tunnel spoil converted into a park. Of course, each material has its own implications in terms of meaning, usability, possible contamination issues, and design possibilities. Some materials, such as war debris—which is dramatically increasing in the current period—carry heavy meanings. Infrastructure-related materials can be unwanted, depending on the public acceptability of the infrastructure itself. I discuss designed landscapes of discarded fill as a category, and I address an under-studied topic interpreting and framing it through design.

The book, published by Routledge, investigates this topic from a cultural, technical, and design perspective. It begins by defining and unpacking the term discarded fill, then examines its growing production. It shows that we now move more sediment through human activity than natural geological processes do, drawing on estimations by geologists and linking this condition to the discourse on the Anthropocene.

As Kevin Lynch highlights in Wasting Away, there is no longer an “away” where waste can be placed. The growing production of discarded fill, while it began rising with industrialization, accelerated after the 1950s during the so-called Great Acceleration period. I argue that we urgently need to reduce the production of discarded fill upstream, but also that there is a need for larger design involvement downstream.

The book argues for a visible and legible treatment of these materials, for making the presence of waste perceptible within designed landscapes of discarded fill, especially by making legible their constructed nature. I also include technical information—such as possibilities and constraints related to materials such as tunnel spoil and dredged sediments—so that designers can better understand the complexity of working in this field. The book then presents historical and contemporary case studies that embody discarded fill in landscape design.

One chapter is dedicated to a historical precedent from Renaissance Venice that I found particularly intriguing: a never-implemented proposal by Alvise Cornaro in the 1560s to construct an artificial garden hill using discarded dredged material, to be visible from Piazza San Marco. Cornaro also proposed another unbuilt project involving dredged materials to surround Venice with a fortification in water that would have also functioned as a park.

These projects have been studied within architectural history, notably by Manfredo Tafuri, usually in contrast to hydraulic engineering proposals by Cristoforo Sabbadino, who advocated using dredged material to reclaim land and expand the city of Venice. Cornaro’s unbuilt proposals are particularly interesting because they represent, to my knowledge, the earliest precedents proposing a design use for discarded dredged material. They also represent early precedents of a public garden or park.

Importantly, these projects have not been studied from the perspective of landscape architecture/landscape architecture history, whereas they are relevant for the discipline and to be included.

The book as a whole argues for the legibility of constructed landscapes made of discarded fill. Making this constructedness visible helps convey the artificial nature of these landscapes and, possibly, raise awareness about the waste embedded within them. I analyze many case studies in terms of legibility, ranging from highly sculptural landforms to more subtle strategies.

The book then focuses on three main case studies. Two are examples of concealment through natural-looking landscapes and camouflage respectively, and one is an example of high legibility.

The first is Spectacle Island in Boston, designed by Brown, Richardson + Rowe Landscape Architects and Planners. It uses tunnel spoil from the Big Dig project, along with dredged material, to transform a former landfill into a park.

The second is a depot in Sigirino, Switzerland, by Atelier Girot. It was constructed using tunnel spoil from the Ceneri Base Tunnel of the AlpTransit Gothard axis. Sigirino depot is interpreted as an example of subtle design camouflage.

The third case is the Tejo and Trancão Park in Lisbon by PROAP and Hargreaves Associates, which uses excavated material from Expo ’98 construction sites and some dredged material. The topography is given strong legibility, resulting in an almost sculptural character in some areas, subtler in others.

Overall, the book aims to provide readers with technical, cultural, and design knowledge on an under-studied topic. It addresses technical issues such as slope design and topsoil construction, as well as aesthetics, possible design approaches, while continually emphasizing the role of the designer and what landscape architects can contribute in these contexts. It also relies heavily on images, including photographs of projects under construction, to support its narrative. I see the book as an original contribution to the field of landscape architecture.

Although based on academic research, it seems the book can also be used by practitioners. Would you describe it as a manual or more as a catalogue?

It is also very much intended for practitioners. I studied the main case studies in depth, speaking directly with the landscape architects or, in some cases, the engineers involved. I gave information on construction phases to better understand and unveil ongoing processes like the construction of the slopes and topsoil. For instance, I had the chance to visit and document the yard of Sigirino depot, in different stages.

Rather than a manual, I would describe the book as a catalogue of cases and design approaches (despite not structured as a catalogue). I draw conclusions and reflections by addressing real constructed cases. Constraints related to contamination and regulation vary widely between countries, so each project is discussed on a case-by-case basis, including how it was constructed and materials embodied. The designed landscapes are commented on in terms of aesthetics, spatial opportunities provided by strata of fill, as well as the contributions of the designers. Many of the cases constitute large-scale projects rather than small-scale ones, which reflects the complexity of working with discarded materials.

If a practitioner is faced with designing a project involving discarded fill, the book can serve as a reference for both design strategies and technical considerations.

When you discuss concealment and legibility, the book clearly engages perception. Would you say it can also be interesting in regard to the perception of processes in landscape architecture in general?

Returning to the core question of what landscape architecture can contribute to technical fields, I am interested in pushing the boundaries of design agency in contexts where designers are not usually involved. I focus both on processes—especially understanding the origin and destination of materials, and the flows involved—and on spatial and compositional issues. I am particularly interested in the possibility of conveying the presence of made ground in these landscapes, which relates to perceptual aspects. Perception is a complex field because it depends on the individual observer, but certain relationships or issues can be made legible. For instance, allowing people to perceive topographical differences may prompt questions about what a park can embody in terms of materials. Processes in landscape architecture also refer to ecological succession over time and to the potential of landscape as a driver of city formation processes (landscape urbanism). These aspects are also considered in the book.

I describe a spectrum from concealment to legibility. Legibility can be achieved with sculptural approaches or with more interesting, subtle strategies, such as constructing geometric mounds, marking edges or juxtaposing “closed forms” with open-ended processes. Concealment includes pastoral or natural-looking landscapes, restorative approaches, and camouflage.

Given contemporary representations of nature in urban landscapes, do you find concealment problematic?

Sometimes concealment responds to social expectations, as people often prefer landscapes that appear “natural”. However, my position is consistently in favor of legibility.

The book seems particularly relevant today, given that the mass of human-made objects has surpassed global biomass.

I focus on the made ground and I include graphs and sediment movement estimations to show how significant these processes have become and how we produce discarded fill at increasing rates. What might appear as a niche topic is in fact deeply connected to global material flows and is a relevant field of action.

Did you observe a tendency to minimize soil movement in contemporary practice?

Designers need to become increasingly aware of material flows. Bringing material to a site implies extraction elsewhere. Understanding the origin, destination, and meaning of material is crucial in today’s practice.

Are we entering a period of unmasking the production of space?

I think this is a direction we may move toward, but this attitude is not yet widespread.

The book includes cultural issues, reflections on material flows and questions of spatial legibility. Which intellectual frameworks or figures were particularly formative for the way you approach landscape today, broadlyspeaking?

My path in the field began with my studies in architecture, where I did a thesis in landscape architecture addressing land reclamation from a design perspective. It continued through a PhD completed in 2015 jointly awarded by Politecnico di Milano, Torino and Bari (Scuola Interpolitecnica di Dottorato), which included a period at Harvard GSD as a special student (visiting) in the Landscape Architecture Department (AY 2012-13). My PhD thesis was titled Designing Landscapes with Discarded Fill, which I later largely modified and developed with new research for several years to become the book Moved Earth. My main early influence in the landscape architecture field was the discourse on landscape urbanism by Charles Waldheim, its emphasis on process, and issues of representation of processes. Later on, I focused more on other approaches that reasserted spatial and perceptual qualities or that reflected on “legibility,” such as the work of Julia Czerniak, Anita Berrizbeita, and Karen M’Closkey.

These references are present in the book. The discourse on planetary urbanization, advanced by Neil Brenner and Christian Schmid in 2012, was also important, particularly in relation to mapping material flows and connections between extraction and consumption sites, fostered also by the UTL lab at Harvard at the time. Kevin Lynch’s Wasting Away was a key reference, as well as a text on artificial mountains by Michael Jakob published in Landform Building, and Pierre Bélanger’s work emphasizing mapping flows. Overall, the book is an original research project and reflects my interest in soil and in bridging technical issues and spatial design.

What should landscape architecture learn to embrace rather than avoid?

Landscape architecture should actively engage with technical fields such as displacement and design of discarded fill, energy landscapes, land reclamation, and up to small-scale interventions like desealing. These can be interpreted from a design perspective. Designers can bring their expertise to multidisciplinary environments, contributing to the construction of more significant landscapes, going beyond the merely technical.

Do technical professions still see landscape architecture as post-engineering beautification?

I think there is this tendency. Early involvement in the process is essential. Designers must be engaged from the beginning to avoid being relegated to ex-post embellishment. Constructing a shared language across disciplines during the process is one key. Design can significantly enhance diversity, use, and aesthetics.