This guest post comes from Krissy Hopkins, a graduate student in the Department of Geology and Planetary Science at the University of Pittsburgh. Krissy has been getting her feet wet in the Panther Hollow Watershed and contributing her research skills to the Pittsburgh Parks Conservancy for years.
For the past three years I’ve fixated on learning as much as I can about the Panther Hollow Watershed, which includes parts of Schenley Park and Squirrel Hill. How many people live in the watershed? How many buildings are there and when were they built? When rain falls on the watershed where does it go? Where does the water in Panther Hollow Lake go? I want to know how this landscape changed over the last century.
This may seem like an odd fascination. However, to a graduate student studying how urbanization impacts aquatic ecosystems it is spot on. My research uses a bit of detective work to understand how people change the land and how our decisions impact the health of local streams and rivers.
My latest research project reconstructs the expansion of development in Panther Hollow since 1870 and estimates how this development has impacted Schenley Park’s streams. Using historical maps, aerial photographs, and U.S. Census records, I created a series of maps for each decade since 1900 showing the location of roads, buildings, and sewer lines in the Panther Hollow Watershed. To assess the impact of development on the streams, I developed a simple model to predict changes in the amount of water flowing through the streams in Panther Hollow since 1900. Results from this project were recently published in the journal Landscape Ecology.
My research shows that roads and rooftops covered only 3% of the watershed area in 1900. These surfaces now cover 27% of the land area — a big change! Prior to 1900, the watershed was an agricultural landscape with seven large lots containing only 29 buildings. Panther Hollow’s streams flowed west through the Squirrel Hill neighborhood into Schenley Park, eventually draining through Junction Hollow to the Monongahela River. Two main dirt roads (Forbes and Shady) ran through the eastern portion of the watershed. Residents disposed of sewage in pit-style outhouses and obtained drinking water from local streams.
A transition from agriculture to urban land use occurred between 1890 and 1920. Development was concentrated in the eastern half of the Panther Hollow Watershed, while the lower watershed remained part of Schenley Park. Between 1890 and 1911, approximately 10 miles of brick and clay sewer pipes and 6.5 miles of roads were installed in the watershed.
To make room for development, the streams through Squirrel Hill were piped into the sewer system and diverted out of the watershed through a sewer main along Greenfield Avenue. As a result, the streams in the eastern half of the watershed no longer feed the Schenley Park streams. The watershed was cut in two! The remaining above-ground streams in Schenley Park have about 50% less water flowing through them every year. Sometimes in the summer months these streams have little to no water flowing through them — bad news for aquatic life that call the stream home.
Schenley Park has also changed. Around 1904, Panther Hollow Lake and a pipe connecting the lake to the sewer system were constructed. Now, even the remaining above-ground streams eventually flow into Pittsburgh’s combined sewer system. The system channeled raw sewage, street runoff, and stream water directly into the Monongahela River until 1959. That year, the city installed sewer mains along the river to collect sewage to be sent to the new treatment plan along the Ohio River. However, when it rains the pipes are too small to hold all the water, causing excess water and sewage to flow into the rivers to this day. In 2010, 11 billion gallons of sewage and stormwater flowed into the Pittsburgh’s rivers!
As the Pittsburgh Parks Conservancy continues to work on restoring the Panther Hollow Watershed, research like mine helps them better understand how development impacts the ecosystem. Knowledge of past impacts can help better target restoration efforts in the future and restore this watershed back to health.