Collapsing sluice house at Lock 68 along the Manayunk Canal Tow Path in 2014. | Photo courtesy of Sandy Sorlien, from her book Inland: The Abandoned Canals of the Schuylkill Navigation

Once there was nothing but a free-flowing river amongst the trees. Then came a quick splash of industry: boats carrying coal, timber, and foodstuffs. But eventually, all went to ruin. And now, to renewal.

That’s the story of a little pocket of Philadelphia hugging the banks of the Schuylkill River in Manayunk and Roxborough. Many residents know well the mysterious ruins long-hidden within the trees off the Manayunk Canal towpath northwest of Main Street. A dilapidated brick structure housed archways, doorways, and large rusting gears, like some ancient graffiti-adorned temple. A few dozen yards away, a long concrete weir jutted out into the river like a sea wall, inviting a perilous journey out above the Flat Rock Dam’s raging waters.

A person paying any attention could guess at the past purpose of such ruins: the headworks of a canal that still serves as a spine of Main Street Manayunk. But fewer likely know the full story of the canal’s history, or that access to the nearby ruins will also now be a thing of the past, as the City works to bring the location into a new era.

Gears to control the gates of the sluiceway in 2017. According to the Philadelphia Water Department, these will be displayed at the site.| Photo courtesy of Sandy Sorlien, from her book Inland: The Abandoned Canals of the Schuylkill Navigation

In early September, the Philadelphia Water Department (PWD) announced a closure of a portion of the towpath, which also serves as a portion of the Schuylkill River Trail, through the end of the year as it spends around $15 million to overhaul the canal. PWD is clearing and regrading the area around the headworks, transforming it from derelict to a semi-functional facility that will re-establish freshwater flow into the canal for the first time since the 1940s.

Additional downstream work will also improve water quality in the canal, capping a multi-year effort to eliminate pollution and foul odors that creep up from its stagnant water, particularly during the hot summer months. “We’re going to be restoring some flow. That should, in theory, reduce odor issues and reduce [scum],” said Peter Reilly, an engineer for PWD.

As the headworks will now be redeveloped and closed off to the public, Philadelphians will lose a place of urban adventure. However, the history will remain fully in view, perhaps more so than ever, for those who care to look.

Coal in the North

A lithograph form 1827 showing Flat Rock Dam on the Schuylkill River. | Image courtesy of The Library Company of Philadelphia

Sandy Sorlien, environmental photographer for the Fairmount Water Works, knows well the history of the Manayunk Canal and similar structures populating eastern Pennsylvania. In summer 2022, she published Inland: The Abandoned Canals of the Schuylkill Navigation, chronicling their centuries-old history.

While commerce in Philadelphia’s first century was centered along the Delaware River, officials and industrialists began to look west to the Schuylkill River by the turn of the 19th century. In 1815, the state legislature issued a charter to the Schuylkill Navigation Company to begin building out canal works along the Schuylkill River to facilitate commerce between Philadelphia and upstream cities like Reading and Pottsville.

However, the state did not provide funding, leaving the company to struggle to raise private funds. It ultimately came to rely on the backing of wealthy Philadelphians such as Stephan Girard. In addition, odd logistical stipulations further hampered construction of the canal. “The charter stated they had to start building simultaneously from the top half down and bottom half up and meet in Reading,” Sorlien said. “That wasn’t the most efficient use of engineers and designers, because of all the travel back and forth.”

Still, the effort eventually was successful. In 1818, the 20-foot-tall Flat Rock Dam was constructed to begin funneling water into the two-mile-long Manayunk Canal, the first dam completed by the company. By 1824, the river became navigable to Reading, and eventually, Sorlien explained, the canal network stretched 108 miles, from Center City’s waterworks into the headwaters of the river in Schuylkill County. But the canal and its towpath were not continuous, as the company used straight, calm portions of the river for direct navigation and only built canal works when needed.

“It went in and out of the river. There were slack water pools behind dams that would form a pool of navigable water for several miles,” Sorlien said.

The route was also littered with locks. According to The Encyclopedia of Greater Philadelphia, the system had 120 locks over its 108 miles, compared to just 83 for the 363-mile Erie Canal. Today, the locks bookending the Manayunk Canal (Lock 68 upstream and Locks 69 and 70 toward the city) leave it as the only vestigial canal with locks still visible at both ends.

A Swift Rise and Not So Swift Fall

Stock certificate for the Schuylkill Navigation Company from 1874. | Image courtesy of The Library Company of Philadelphia

For a time after the canal’s construction, business boomed. When originally dreamed up, industrialists had the shipping of goods like timber and food in mind. However, technological advances in burning anthracite coal changed everything. Early American industry was powered by bituminous coal largely imported from England, yet naval blockades during the war of 1812 forced companies to look inward to anthracite coal, which was abundant in Pennsylvania.

In 1808, a tavern owner in Wilkes-Barre named Jesse Fell discovered a method to use anthracite coal for home heating, recalls a 2022 article in the Times-Leader. Around the same time, Sorlien said, a pair of Philadelphia industrialists named Josiah White and Erskine Hazard discovered by accident an efficient way to burn this hard, stubborn form of coal. As history has it, the men and their employees were experimenting with how to get the coal to ignite at a factory near East Falls, when, frustrated, they swung a furnace door shut and went to lunch. When one returned about half an hour later, they found the furnace burning red hot. “They almost accidentally found out that you have to get it really hot and leave it for a long time and then it burns like crazy,” explained Sorlien.

The confluence of these events opened the floodgates for the canal trade, dominated by shipments of coal to power Philadelphia homes and factories. Almost immediately upon opening the entire canal in 1825, Sorlien said, the Schuylkill Navigation Company realized it had built the system too small. In the 1830s, it engaged in a significant renovation to double the number of locks, and in 1846 the entire system was shut down to rebuild everything to accommodate bigger boats.

A 1922 reproduction of a drawing of warehouses and coal wharves on the Schuylkill River. | Image courtesy of The Library Company of Philadelphia

While some conventional wisdom holds that the advent of steam-powered freight trains in the first half of the 19th century quickly made the canal system obsolete, Sorlien said that is not entirely true. While the profit-making heyday of the canal indeed did stretch only about 20 years into the 1840s, the Schuylkill Canal system saw its most volume in the 1850s.

By then, rail industry was eating into profits, but it was repeated, damaging flooding events that really stung the canal’s bottom line. A “last straw” came during a particularly bad flood in 1869 that decimated canal infrastructure along the Schuylkill River. The following year, the Schuylkill Navigation System was leased to the Philadelphia and Reading Railroad Company and in the decades ahead would change hands several more times as its footprint and commerce dwindled. The last commercial cargo shipment came in 1931. The system was left to ruin from there.

Cleaning Up

The ruins of the Flat Rock Dam sluice house in 2014. The lower brownstone structure with three arched openings has been preserved, as has Lock 68 next to the trail, but most of the brick walls of the old sluice house have been removed. | Photo courtesy of Sandy Sorlien

When canal commerce went kaput its legacy of pollution remained. In the late 1940s the Commonwealth of Pennsylvania purchased the remnants of the canal works and went about the Schuylkill River Desilting Project, a successful, multi-year effort to dredge the river bed of more than a century’s worth of coal silt, which had made it one of the most polluted rivers in the country.

On a smaller scale, water quality problems in the Manayunk Canal remained. Staff with PWD said that until recent years, the canal suffered from two problems: runoff and sewage from Manayunk would collect in the waterway, which was also stagnant ever since the shuttering of the canal. That created odor issues for residents, while also risking pollution to the Schuylkill River in the event of an overflow, a problem given a drinking water intake is located just downstream.

PWD staff said they first addressed the stormwater problem with the installation of a large underground holding tank installed under Venice Island a decade ago. But now comes part two: a $15.5 million project funded by a loan from the state PENNVEST program to restore flow to the canal.

Work started in the fall of 2022 and ramped up this summer, leading to the closure of a portion of the trail through the end of the year. Once fully completed, estimated in fall 2024, a new canal intake structure will pump fresh water into the canal, and new infrastructure downstream will return it to the river, creating flow and further cutting down on pollution and odor.

Rendering of the Flat Rock Dam Betterment project. | Image courtesy of the Philadelphia Water Department

Reilly, the engineer for PWD, said the project also gave the department a chance to address the temple-like ruins northwest of Main Street. As PWD is restricted from spending money on projects unless they have a direct water quality component, he said it was unable to take action on the site until this opportunity presented itself. The department looked at potentially trying to fully restore and potentially reuse the ruinous building there, a former sluice house that regulated the amount of water in the canal, but determined it wasn’t feasible and demolished most of the upper parts of the structure. “The building had started to collapse. We were aware that there were people accessing it. I can’t lie and say I wasn’t one of them. I was a kid growing up in Mt. Airy,” Reilly said. “But when it really started to fall apart it was a safety hazard.”

Visualizations of the renovation of the site show clearance of most of the trees and silt replaced by new concrete access paths and an adjacent stormwater basin to help mitigate flooding concerns. Much of the area will now be fenced off from the public.

However, the department is keeping the remaining walls of the old sluice house to about knee height, removing the graffiti, returning large metal gears that used to power the locks, and placing historic signage along the trail to explain the history of the site to passers-by. So while some Philadelphians may remember wistfully their days of being able to explore the ruins, the greater public will now have a better opportunity than ever to learn about the history of the canal’s headworks. “You will be able to see the lower stone structure, which will all remain,” said Reilly. “The final flow will go through what was the original lock on the trail side of the structure.”