Wed Oct 7, 02026, 6:30PM EDT
Laura Jasinski
Restorative Ecology: The Charles River Floating Wetland
The Charles River Floating Wetland explores an ecological intervention to reduce harmful algal blooms in the river, which threaten the river’s health and limit the feasibility of swimming.
How do you restore a river’s ecology when you can’t go back to what it was?
The Charles River once had marshy banks that filtered pollution and sheltered the food web, including the zooplankton that eat algae. Today it has seawalls and algal blooms that can close swimming access for weeks. Laura Jasinski, Executive Director of the Charles River Conservancy, spoke at the Foundry in Cambridge about the Conservancy’s floating wetland, a pilot project in the river since 02020, and about how a small nonprofit makes long-term change.
Event Summary
How do you restore a river’s ecology when you can’t go back to what it was?
The Charles River once had marshy banks that filtered pollution and sheltered the food web, including the zooplankton that eat algae. Today it has seawalls and algal blooms that can close swimming access for weeks. Laura Jasinski, Executive Director of the Charles River Conservancy, spoke at the Foundry in Cambridge about the Conservancy’s floating wetland, a pilot project in the river since 02020, and about how a small nonprofit makes long-term change.
Jasinski began with the organization itself. The Conservancy is 26 years old, has a staff of ten, and is a roughly $1.5 million operation, about 90% of it private philanthropy. It acts as a friends group to the Department of Conservation and Recreation, which owns all the land it works on. Rather than leading with doom and urgency, it aims to turn people into advocates through connecting, creating, and celebrating. She framed its work as impact through collective action, coalitions, engagement, and experience.
On collective action, the volunteer program brings in over 2,000 people a year for trash cleanup, benches, tree care, and invasive species removal. It has logged more than 37,000 volunteers and $2.5 million in donated labor, which matters for a chronically underfunded state park system. Massachusetts ranks last nationwide in per-capita state park spending. Volunteers have also helped cut invasives in Hell’s Half Acre from about 80% coverage in places to about 30%. At the Lynch Family Skate Park, years of youth-led engagement produced a permanent free wall for graffiti and an artist-in-residence program. And once a year, City Splash lets about 320 people swim in the river, which she called the fastest way to create a Charles advocate.
The wetland grew out of that swimming goal. Phosphorus-fed algal blooms are a major obstacle, since a bloom can close the water far longer than a storm can. The 730-square-foot island has a recycled-plastic buoyant core and a coconut-fiber surface, and its plants grow hydroponically with roots hanging in the water. It was towed to its mooring near the Broad Canal along the Longfellow Bridge. About twenty native species were planted, and with little replanting since, the island has done well. It winters at the MIT Sailing Pavilion, where aerators keep the ice off, to avoid spring ice sheets.
The pilot also produced research, including a Northeastern doctoral dissertation measuring zooplankton, phosphorus uptake, and biodiversity. It supports education programs and STEAM kits used in Cambridge classrooms. Its most valuable lesson may be regulatory: permitting 730 square feet took 18 months, because the process for restoring a river is the same one built to block harm to it. The Conservancy has written up the process for others.
The next step is scale. The Conservancy is using a matching grant to hire a design team for a conceptual “floating eco-park” in the Broad Canal. The team is already drafting an operations and maintenance plan for a project that doesn’t yet exist. Jasinski cited Baltimore’s Inner Harbor, Chicago’s Wild Mile, and London’s Canary Wharf as precedents. The floating park would invite people to the water beyond Kendall Square, help with heat resilience, and advance research.