Baltimore’s Inner Harbor has long been a symbol of urban revitalization and economic resurgence. In fact, when ULI bestowed its Heritage Award to the site in 2009, it declared the Inner Harbor was “the model for post-industrial waterfront redevelopment around the world.”
Ayers Saint Gross, an interdisciplinary design firm, led a long-overdue transformation of the National Aquarium with the Harbor Wetland project, an ambitious new initiative—conceived in collaboration with the National Aquarium—to redefine the boundary between the city and waterfront. By rethinking the existing hard edge, the team looked to create a soft border that shows how natural ecosystems can be seamlessly integrated into built environments.
This project not only represents a significant step forward in ecological restoration, it’s also a model for sustainable urban development—especially along historic waterfronts that are well developed. It creates within the Inner Harbor a viable space for native aquatic wildlife and plants to take hold again, with the explicit purpose of underscoring the vital ecological connections between Baltimore and its storied harbor.
Genesis of the Harbor Wetland project
The National Aquarium has always been an active steward of marine life and conservation work. To bolster its efforts addressing declining water quality and disappearing natural habitats—and provide outdoor social and educational spaces—the National Aquarium embarked on a mission to revamp the waterfront. Ayers Saint Gross partnered with the aquarium to conceive of a Waterfront Campus Plan that would become a welcoming civic space that immerses visitors in the natural systems and habitats of the Chesapeake Bay.
Recognizing the opportunity to enhance the aesthetic and recreational value of the waterfront, the idea for Harbor Wetland began to take shape. The vision for the project was rooted in the belief that urban spaces could—and should—coexist with natural ecosystems, providing both environmental benefits and opportunities for public engagement.
From this vision came something no one had seen before: a large, sustainable, park-like floating wetland right outside the National Aquarium on the city’s edge—and free to the public.
Meshing ecology and urban design
Harbor Wetland represents a 10,000-square-foot (929 sq m) floating salt marsh that allows visitors a taste of what the harbor had once been like hundreds of years ago. Creating this oasis from scratch required determination and ingenuity. Buoyancy, water health, and a flourishing ecosystem were the factors that most influenced the final design. By tweaking a pontoon structure that was developed to keep the original prototype afloat, the base of the larger system was conceived. To ensure the habitat’s water was healthy enough to support wildlife, aeration devices were installed at regular intervals across the entire project.
Nearly 40,000 native grasses were then planted to filter pollutants from the water and provide vegetation for wildlife—a critical ecological function. Small aquatic creatures immediately gravitated to the new habitat. The team even saw this in the early prototype stages, with inundations of small killifish. The National Aquarium has documented increased biodiversity over the course of the project’s construction. Today, visitors can see fish, ducks, birds, and dragonflies, and the aquarium is researching the positive influx of healthy biomes at the microbial level. In the long term, these ecological benefits will expand as the native marsh plants grow larger.
In addition, the design includes a network of boardwalks and pathways atop the floating structure so visitors can explore the wetland up close. These paths are integrated with educational signage that explains the importance of wetlands and the vital role they play. The goal is to have a space where people can learn about ecology in an immersive, hands-on way, fostering a deeper connection to the natural world.
It is important to note that Harbor Wetland has successfully withstood a number of severe weather events since its installation—events that are becoming more frequent and extreme. With that in mind, it is anchored to deep pilings designed to withstand a so-called “200-year storm.”
Together, these approaches ensure a sustainable and thriving Harbor Wetland that integrates with the Inner Harbor’s urban landscape. This integration is a reflection of the project’s underlying philosophy—that urban spaces and natural ecosystems can coexist in a way that benefits plants, animals, people, and the larger ecosystem.
A collaborative design process
One of the most critical aspects of Harbor Wetland was the collaborative process that guided its development. At Ayers Saint Gross, collaboration is a deeply ingrained philosophy that drives the firm’s approach to design. Working with the belief that the best ideas emerge when different perspectives are brought together, the team partnered with a diverse group of stakeholders. For example, the design team worked closely with ecologists and marine biologists from the aquarium to ensure that the wetland would function as a viable ecosystem, capable of supporting a diverse range of plant and animal species.
(The full-scale Harbor Wetland evolved from a Floating Wetland Prototype, which Ayers Saint Gross worked on with the National Aquarium and Biohabitats, McLaren Engineering Group, Kovacs, and Whitney & Associates as a continuation of Studio Gang’s earlier EcoSlip concept.)
Additionally, engagement with local, state, and federal agencies helped make the project a reality. Since it was the first of its kind being built, it didn’t neatly align with existing permitting and approval processes. This required a Joint Permit Application (JPA) to both the Maryland Department of the Environment and the U.S. Army Corps of Engineers, which has oversight of the harbor. Following the JPA, all of the normal permitting had to be sought. Ultimately, the various entities were excited by the overall ecological and social benefits and entered into discussions with a desire to move the project forward. In this way, everyone came together to benefit the City of Baltimore and its Inner Harbor.
Community engagement and education
From the outset, Harbor Wetland was envisioned as a community resource, and engaging with local residents has been a key priority throughout the project’s development. The National Aquarium and Ayers Saint Gross worked closely with businesses, schools, and the broader community to ensure that the project serves the needs of the residents while also fostering a sense of stewardship.
Throughout the construction process, the team hosted a series of hard hat tours for various organizations, giving them a behind-the-scenes look at the project while educating stakeholders about the importance of wetland restoration.
As a physical manifestation of the National Aquarium’s mission to connect “people with nature to inspire compassion and care for our ocean planet,” Harbor Wetland is designed to serve as a living laboratory, where visitors can learn about the role of wetlands in urban ecosystems and the importance of ecological restoration. The educational signage integrated into the design provides information on a range of topics, from the specific plant species used in the wetland to the broader environmental benefits of estuaries. At the same time, the space provides a park-like atmosphere with free and accessible seating, shade, and views of the Inner Harbor.
Additionally, the site hosts key educational programs, including What Lives in the Harbor, a free program for Baltimore public school sixth-graders that engages them in researching aquatic species that live in the Chesapeake Bay watershed. Students test water quality in the Inner Harbor to form hypotheses about what animals live there; they then test their hypotheses by conducting an animal survey. After the investigation, students recommend community action projects to improve the local watershed.
The What Lives in the Harbor initiative, on-site summer camps, educational partnerships with scouting organizations, and other civic programs provide hands-on learning opportunities for students to explore the wetland and learn about its ecology in a way that is both engaging and informative. With the opening of Harbor Wetland, these programs are even more interactive, allowing participants to have first-hand experiences with the plants, animals, and ecosystems they are learning about.
As Jacqueline Bershad, vice president of Planning and Design at the National Aquarium notes: “Harbor Wetland serves as a dynamic outdoor classroom, enhancing the aquarium’s existing programs, and providing new opportunities for our community and Baltimore’s visitors to engage in environmental stewardship. Partnering with Ayers Saint Gross allowed us to create a healthy oasis for both people and wildlife using an innovative floating wetland concept. This integrated experience—where science, native animals and plants, and clean water come together—offers a unique environment that is free, open, and accessible to all. We look forward to the meaningful connections this project will foster between all visitors and the vital ecosystems of the Inner Harbor.”
New paradigm for urban ecosystems
Harbor Wetland represents a new paradigm for urban development, one that prioritizes sustainability, resilience, and the integration of natural systems into the urban fabric. By transforming a portion of Baltimore’s Inner Harbor into a thriving wetland, the project is not only restoring ecological balance but also creating space for education, recreation, and community engagement.
For Ayers Saint Gross and the National Aquarium, the project is a testament to the power of collaboration and interdisciplinary design. It is a reminder that the challenges of urbanization and climate change can be addressed through innovative design solutions that prioritize both people and the environment.
As other cities look to integrate natural systems into their urban landscapes, Harbor Wetland offers a compelling example of what is possible. It is a reminder that with vision, collaboration, and a commitment to sustainability, we can create urban spaces that are not only resilient but also thriving, vibrant, and alive.
