When a Fish and a Mussel Team Up, A River Gets Cleaner
In America, few public utilities are enshrined as historic landmarks of engineering, and even fewer are listed on the National Register of Historic Places. The Fairmount Water Works, once a marvel of ingenuity designed to bring clean water to a growing city, is on the list, and recognized as the first successful water supply system in Philadelphia.
The Fairmount Water Works opened in 1815, and provided a new efficient method to supply water to residents throughout the city. “The idea was to engineer a system that could provide good quality drinking water for its citizens in order for the city to thrive,” said Ellen Shultz, Associate Director of Education at the Fairmount Water Works Interpretive Center. “You see this temple to water? This was really an expression of the significance of what was going on.”
According to her, many people settled along the Delaware River, however even in Philadelphia’s early history the Delaware was considered dirty and not a suitable source of drinking water. The Schuylkill River, whose name means “hidden river” in Dutch, was the cleaner.
The concept relied on a pump house to get the water from the river up 90 feet to a reservoir on top of Fairmount, the hill the Philadelphia Museum of Art currently sits on. The water was then on to the neighborhoods through a series of pipes that led all the way across the city to people in Old City and along the Delaware River.
The waterworks was used until the early 20th century. By then, years of dumping directly into the water, along with the industrial revolution, had polluted the water to the point where it was no longer suitable to drink. The building was converted into an aquarium and later a pool, but by the 1950s the building was falling apart, and the river was more polluted than ever.
A renaissance began in Philadelphia in the 1970s when people began to see the historic value of buildings throughout the city. Once the waterworks was listed on the National Historic Register, the Junior League of Philadelphia took an interest in the building, and worked to preserve the crumbling structure.
At the same time, America began to see the devastation pollution was causing, and looked for ways to change the way people treated their environment. By the 1980s, the city decided to convert the existing building to an interpretive center with a focus on educating people on the value of watersheds. Despite the city’s action, the center did not open until 2003.
When you visit the center, you will find interactive exhibits that teach people of all ages the value of watershed protection. The architects incorporated some of the original building into the new center and kept the overall style of the original water works. Stroll through the corridor, and you will see one of the original turbines from the mid 1800s. You can also peer into the dark cavern that once allowed water to flow into the waterworks from the Schuylkill River.
GoPhillyGo recently took a tour of the Fairmount Water Works Interpretive Center, and got a behind the scenes look at their mussel hatchery program which aims to repopulate the river with the once plentiful freshwater mussel.
According to the Partnership for the Delaware Estuary’s website, our region’s streams and rivers were once filled with a dozen different species of freshwater mussels. However decades of pollution have drastically reduced their numbers, and today there are only three species left in the tri-state area.
These mollusks are vital to the ecosystem, and work as water purifiers. The mussels filter out fine organic particulate and deposit their nutrient rich waste back into the riverbed. This provides a food source for other smaller creatures, which become prey for other larger fish.
Kurt Cheng, Shellfish Coordinator for the Partnership for the Delaware Estuary, provided some background on the mussel hatchery, and how these essential mollusks are being reintroduced to the wild.
“These mussels, just by being in the water that they live in, are helping to clarify the water for us,” Cheng said. “We’re in a unique position where we have some of the last remaining freshwater mussels in our region right here in the Schuylkill, right here in the Delaware where you might not think there’s nothing living there,” Cheng said
The process is very interesting, and requires a symbiotic relationship between the mussel larvae and a fish. According to Cheng, most bivalve mollusks, like oysters and mussels, live in tidal saltwaters. The males and females excrete their reproductive materials into the water, where the egg is fertilized. The tides allow the larvae to be carried in any direction, thus populating a much larger area.
Rivers generally flow in one direction, and leave little chance for mussels to send their larvae anywhere but downstream. Their reproductive process requires a curious fish. Once the female’s eggs are fertilized, she holds onto them until they are about the size of a grain of salt. The mussel then waits for a fish to approach, and right as it feels like the fish is as close as it will get, the mussel sprays its larvae at the fish.
The tiny mussel larvae attach themselves to the gills of the fish, and continue growing. Once they have matured, they detach themselves from the fish, and start a new life wherever the fish brings them.
Some species of freshwater mussel even transform themselves to look like something a passing fish might like to eat, which is amazing when you consider that mussels don’t have the ability to see. “Some of them actually produce packets of their larvae that look like a mayfly or something else they will want to eat,” Cheng said.
This is a tricky process in the wild, so Cheng and his group are using science and a little matchmaking to achieve a higher success rate. According to him, a fish is put in a bucket with mussel larvae, and after a short time the larvae attach themselves to the fish’s gills. The fish is then kept in a small tank while the larvae grows. The fish is released back into the river with the attached maturing mussel larvae, and will eventually drop the mussel up-river.
Repopulating the Schuylkill River with these creatures is an essential step in cleaning up the river that was once considered the cleaner choice for city drinking water. Cheng says they will again be spawning mussels this March, and hope to continue having success with these living water filters. “They’re filtering water for us, and we’re trying to help them with facilities like this,” Cheng said. “This is a demonstration laboratory where we can take in mussels, take in fish, and play matchmaker.”
The mussel hatchery itself is not open to the public. However, the hatchery has two exhibits on either side that are open to the public whenever the water works is open. Visitors can also see the hatchery from both sides, but are not permitted to enter the area where the magic happens! Click here to plan your visit to the Water Works.