On a brisk mid-September day, the Philadelphia Water Department (PWD) convened at the northern tip of Venice Island in Manayunk.

Joined by the Younger Member Forum of the American Society of Civil Engineers (ASCE) Philadelphia Section, PWD engineers and public engagement staff showed off an important part of the river’s history: the Flat Rock Dam and the connecting Manayunk Canal.

During the tour, PWD staff explained the history of the dam and canal and the project reconnecting it to the Schuylkill River. Ian McKane, Resident Engineer for the Flat Rock Dam project, led the tour to show the many features of the construction site. McKane has worked on the project from the start of construction when the contract was awarded and will see it through to completion. His experience overseeing the structural work and holding frequent progress meetings provided interesting insights for tour-goers.

Many of those in attendance had the same question: what will happen to the Manayunk Canal once it’s reconnected to the river? Well, after nearly 30 years of planning, and over 100 years since the canal was last used, Philadelphia is about to find out.

A History of the Dam and the Path Back to Flowing Water

Flat Rock Dam, located on the Schuylkill River where Philadelphia and Montgomery counties meet, once supported the surrounding coal-dependent industries of the 1800s by funneling water into the factory-lined Manayunk Canal.

The dam and canal were part of a 108-mile system of locks and dams built in the 1820s by the Schuylkill Navigation Company. The waterways were used to transport coal down from Port Carbon, located almost 90 miles upstream from Philly, to downstream factories that once existed in Manayunk and elsewhere along the Schuylkill River.

The historic Manayunk Canal was closed to navigation in the 1940s, as railroads replaced the need for boat transportation. This also removed the flow of fresh moving water from the Schuylkill River. Fresh flow has been cut off for decades, leading to stagnant water, odors, and trash.

The restoration of the dam has been a long road. The planning for this project began in the 1990s – 30 years ago! – when PWD recognized the importance of flowing water through the canal.

After years of planning and preparations, the Flat Rock Dam Betterment Project officially started construction in fall 2022 to reconnect the Manayunk Canal with the Schuylkill River. After consulting the existing community about their concerns about the project, a bold new vision was created for the dam.

Community and Environmental Impacts

Investments in the Manayunk Canal and Flat Rock Dam will assist Philadelphia in meeting Clean Water Act regulations and source water protection obligations. The improvements will also protect drinking water sources for Philadelphia, which relies on the Schuylkill River for nearly half of its water supply.

This project will also improve water quality for Manayunk Canal and Schuylkill River wildlife. The canal’s current lack of flow creates stagnant water conditions, which lead to potentially harmful algae blooms, high water temperatures, low oxygen levels, and seasonal local odor issues.

This project also improves aesthetics along the very popular Schuylkill River Trail, which runs beside the Manayunk Canal. Trail users can view the preserved historic lock, gatehouse structure, and mechanical artifacts used to introduce flow into the Manayunk Canal when it was first built 200 years ago.

Educational signage displayed on the trail will inform the public about the history of Flat Rock Dam and the purpose of the canal. The improvements PWD is making at Flat Rock Dam will aid in preserving Philadelphia’s infrastructure history for the next generation to learn from and enjoy.

Approaching the End of Construction

The Flat Rock Dam Betterment Project is approaching the end of its construction work. While the project was expected to complete construction by Fall 2024, AP Construction now expects its work to be completed by Spring 2025. This is due to unforeseen delays throughout the 2.5 years of active work.

Helpful Timeline Information:

• Active construction will continue through the winter with the removal of the temporary cofferdam.
• There will be a series of safety and quality tests performed throughout the winter that will ensure the proper restoration of water flow to the Manayunk Canal.
• New greenery will be planted in Spring 2025 during the April-June planting season.

PWD will host a ribbon-cutting event in Late Spring 2025. There will be more information about this to come.

How this project was possible

This is a collaborative project with many partners. Philadelphia Parks and Recreation (PPR), the Army Corps of Engineers, the Pennsylvania Department of Environmental Protection, Pa. Historical Museum Commission, and other partners made this project possible. The project is being financed with support from a low-interest $20.7 million loan from PENNVEST, the state’s revolving loan fund for water infrastructure improvements. Manayunk Development Corporation and Philadelphia Canoe Club have helped PWD spread the word about this project.

Read more about the Manayunk Canal at the Philadelphia Water Department.