Urban Ecology: Crossing Boundaries


Urban Ecology: Crossing Boundaries


Charlie Cotton
Rhode Island School of Design


Laura M. Briggs & Jeff Geisinger
Rhode Island School of Design



Integration with nature and wildlife gives people a better appreciation of the natural world. This project uses long, raised spans to respect the environment and allow for nature and animal interaction. The jury appreciated the narrative and bioclimatic design. Although the design is to be sensitive to the environment, the jury is concerned whether a delicate site like this should be built on.


Project Overview

At an intersection of post-industrial Central Falls, RI and the polluted Blackstone River, a housing project creates a crossing point for human and wildlife communities. Though Central Falls is surrounded by river, the city has limited access to wilderness. Though wildlife can move along the Blackstone River Corridor, there is little large-scale habitat to harbor growing populations. This project proposes solve these problems simultaneously by creating an intersection for these communities, where fifty-six dwelling units form a boundary around a wildlife refuge. The boundary breaks strategically; to admit wildlife moving along the Blackstone River Corridor and beckon to the Central Falls community. Apartments are accessed by way of a public boardwalk that reaches into the refuge. The river and wetland spill underneath this boardwalk, inviting wildlife into the site. This inter-species overlap echoes at the scale of community spaces and private dwellings, creating an ever-shifting interaction between old neighbors with a new proximity.

Land Use

The ground surface of the project is divided into a small urban plaza at the western edge of the site and a large central area for wetland habitat restoration. The existing site is composed in reverse, with a large area central area of asphalt parking and  habitat finding its way into landscaping at the fringe. Wetland restoration focuses on creating habitat for the smoky shrew, which is a threatened species in Rhode Island. The smoky shrew is an important wetland rodent that feeds on native amphibians, reptiles and insects and is a major food source for local predators such as fox, mink and other charismatic megafauna. The shrew shares habitat characteristics with other threatened species in the area, the bog lemming and the common nighthawk, which would also likely take advantage of this wetland ecosystem. The shrew is a key piece of a thriving Rhode Island wetland ecosystem, and thus a key to forming a successful human-wildlife relationship on the site.

Regional / Community Design

The project is situated at a historical, economic, and ecological joint in the city of Central Falls. Sandwiched between the railroad, the river and the highway, the site lies at the eastern edge of Central Falls. The proximity of the highway allows young professionals working in Boston and Providence easy access to renovated mill buildings along the river corridor, while the sunken railroad bypasses the community and splits the city center from this edge revitalization. The project addresses the community across the railroad tracks by opening its boundary to pedestrians along the axis of a major cross street. Access to wilderness, public spaces for growing, selling and buying local food, and mixed-income housing all aim to provide opportunities for the community of Central Falls. The form of the project references neighboring mill buildings in scale and site, allowing the river to flow underneath the building for the sake of ecology rather than industry, seeking to create a new economic paradigm for the region.

Design and Innovation

The project aims to address sustainability by integrating economic and ecological communities in Central Falls, remediating problems caused by industrial mills, increasing ecological resilience, and providing a sense of peace and respite in wildness. Public spaces oriented around land stewardship, like beekeeping, composting, urban gardening, and a market, allow mixed income-residents to generate revenue for Central Falls, contribute to the wild lands they live in, and socially interact while providing fresh food. The form of the project activates this potential: the western wing which contains the market addresses the neighboring mill building and the city, and the eastern wing which contains the remaining public program crosses over the river. The placing of these spaces navigates the transition between urban and wild, providing residents agency between their economic and ecological communities. These community spaces also support the remediation of the wetland and the cleaning of the river. The project allows the river to run beneath it like an industrial mill, appropriating this typology to support the local ecology and thus encourage a renewable economy from a destructive precedent.

Water Cycle

The site is transformed from a parking lot into a wetland ecosystem, which retains and remediates some pollutants from the Blackstone River. A green roof / garden collects greywater for domestic use, and all water used domestically passes through a living system before being discharged into the Blackstone River watershed. The wetland ecosystem and green roof work together to manage 90% of the water from a two-year flood event on site.

Materials and Construction

The project is structured as a beam composed of CLT panels that run the length of the building. The CLT panels create both the structure and the space of the project, and openings are located to allow the assembly to function as a beam in moment and shear. Despite the span of the project over the river, no extraneous support is required. CLT is sourced regionally from the Quebec area, and harvested from young-growth forests that are quickly renewable. This allows the project to operate as a carbon sink. Mineral wool insulation, though high in embodied energy, is sourced and recycled locally. A cedar rainscreen weathers naturally over time. Permeable concrete pavers for the urban plaza reduce the amount of concrete material used while also reducing water runoff.

Bioclimatic Design

The building is arranged as a single-loaded corridor with a boardwalk as the main point of access, and stairs serving blocks of units. Each block contains 8 units, which share an insulation envelope and plumbing services. This allows efficient use of water and energy resources by increasing adiabatic heat transfer between units. The single-unit depth is 28 feet, narrow enough to provide ample solar gain and natural ventilation through the entirety of each unit. All units have sections of operable wall that can be opened to varying degrees according to occupant comfort. This strategy augments natural ventilation. Because the project bounds a microclimate, the pressure differential between the river and refuge areas also supports natural ventilation.

Energy Flows and Energy Future

The above metric evaluates the building’s performance in several design iterations. The leftmost bar shows energy use for a code-compliant building. The next bar over adds the insulation value for the walls and roof of the project, and the performance of the in-unit ERVs, passive-house standard envelope and water-source heat pump to reduce the building’s energy footprint significantly. The fenestration is designed to reduce heating load in the winter and cooling load in the summer. The following bar considers the natural ventilation set up by the project’s creation of a microclimate. The last bar includes the window shading; glazing is recessed into the façade to a depth of 13 inches, blocking much of the summer sun while allowing the entirety winter sun to penetrate the envelope.

Light and Air

Because the mass is one unit deep, all residents have access to windows on two sides of their unit.   While some apartments face E-W and others face N-S, all apartments are well-lit with both direct and indirect sunlight - during 93% of occupied daylight hours.  This also ensures two views for each resident. Every unit faces the wildlife enclave bounded by the project. E-W facing units also overlook the street with distant views of the river, while N-S facing units have a view directly overlooking the river.

Collective Wisdom and Feedback Loops

The challenge of this project is to integrate the inhabitation of two diverse constituents in one place, and to help those constituents support each other over time. If the design succeeds in this endeavor, the Central Falls community will gain a wealth of knowledge from this wildlife refuge and the wildlife will gain a strong foothold in the community. This can become a self-perpetuating cycle if measures are taken to ensure that wildlife is thriving in the space designed to receive it. This collective community growth will take time and stewardship, which would depend on the involvement of residents. The success of the project both depends on this feedback loop and builds on it.

Long Life, Loose Fit

At the outset, this project envisions a constantly shifting mode of occupation. Flexible apartments will allow some residents to give parts of their apartments back to wildlife, some residents to have outdoor patios and gardens, and some residents to stay inside. The façade will be a mosaic of the human-wildlife dialogue in flux. Community spaces will add to this dialogue, mediating between the urban plaza and the wild wetland. These spaces too are in flux, given over to an interspecies relationship presently in the form of composting, greenhousing, beekeeping, gardening and selling. But the design of these spaces is not deterministic. Community spaces could become spaces for bats and birds, and the open nature of the apartments could allow for this pattern to continue into more private spaces. The project is shared territory, and how this sharing proceeds in the future will be determined by the next generation of inhabitants.