Philadelphia Water Department celebrates Manayunk Canal’s restoration and reopening

Philadelphia’s Manayunk Canal was a stagnant water body that suffered from low dissolved oxygen, frequent algal blooms and sedimentation for nearly 80 years after its closure in the 1940s. 

The canal, which connects to the Schuylkill River, one of Philadelphia’s primary water sources, is a part of a significant waterway for the city. That’s why in 2022 the Philadelphia Water Department launched its Flat Rock Dam project, which sought to restore healthy, flowing water through the dam and into the Manayunk Canal.

On April 14, the canal was reopened.

The project “strengthens our infrastructure, supports aquatic life and restores a historic waterway that means so much to the neighborhood and to our city,” said Laura Copeland, the Water Department’s assistant deputy commissioner for education, community engagement and government affairs.

Approximately 10 weeks after the canal reopened, the department has observed improvements in water flow and quality, and a decrease in pollutants. Further, larger fish species, like gizzard shad and striped bass, have reappeared. 

The Water Department held a ribbon-cutting ceremony at the canal on Thursday to celebrate the completion of the project with city officials, community members and project partners.

A quick history of the Manayunk Canal

The Flat Rock Dam was constructed in 1818 to carry water into the later-constructed Manayunk Canal, according to Domenic Rocco, the bureau director of waterways, engineering and wetlands at the Pennsylvania Department of Environmental Protection.

The canal served as a route for commerce to travel between Philadelphia and upstream areas. The primary product transported via the canal was coal, which “fueled the industrial revolution,” and helped make Philadelphia “the workshop of the world,” according to Adam Levine, a historical consultant to the Water Department. 

Read more: Manayunk Canal reopening will improve water quality but prevent people’s access

The canal’s presence stimulated development in Manayunk, Philadelphia. In the decade after the canal opened, the neighborhood’s number of factories and residents grew significantly, according to Levine. 

Through the late-19th and mid-20th centuries, the canal faced decline. Pollution from factories, damage from natural disasters and transportation competitors all led to the canal’s closure.

Around 1940, a bulkhead was placed to separate the canal from the Schuylkill River, and the Flat Rock Dam’s gate house was abandoned, Levine said. What followed was decades of neglect, which contributed to the poor ecological conditions. But in the 1970s, restoration efforts began.

An early iteration of the Flat Rock Dam project began in 1999, and went through numerous design phases before it became the version of the project that was ultimately carried out.

How the project was completed

Much of the project was funded by a $21 million grant provided by the Pennsylvania Infrastructure Investment Authority (also known as PENNVEST), which provides low-interest loans and grants to water quality improvement projects in Pennsylvania.

The project involved improvements to dam and canal structures, as well as protection of historic elements and wildlife, according to Ian McKane, a civil engineer specialist for the Water Department. 

A historic lock structure, towpath and gate house, among other historical elements, were preserved throughout the project’s implementation, according to David Weld, an assistant manager of the design branch at the Water Department. 

During construction near wildlife habitats, a biologist was on site to capture any fish and turtles in harm’s way and return them to the Schuylkill River, McKane said. 

What’s next for the canal

For now, the canal remains closed to all recreational activities because of potentially dangerous currents and other safety concerns. 

However, upgrades to the canal are not coming to a halt. The Fairmount Waterworks is working on a project to populate the canal with mussels to propagate a new mussel population in the Schuylkill River. If the project succeeds, the diminishing population of mussels will rebound while they filter water in the canal and river. 

Other work includes riparian restoration and native plantings along the stretch of the canal, according to the Water Department.  

“The whole system, now, is bettering itself,” said Lance Butler, a senior scientist for the Water Department. “It’s becoming more stable, it’s becoming healthier … it’s becoming more diverse.”

Butler added: “You can see organisms start to recolonize and immigrate. Energy flows are increasing, so the sky’s the limit in this place.”