The Spring Creek watershed lies along the eastern edge of the Appalachian Mountains, which extend from Maine to Georgia. Geologically,the Appalachian Mountains are divided into physiographic provinces (Figure 1).
Figure 1: Physiographic Province Map of Pennsylvania. Click to open a larger PDF version.
The Spring Creek watershed is situated in the Ridge and Valley Province that has a southwest-northeast orientation, extending from northern Maryland to northeast Pennsylvania. This province is characterized by long, narrow ridges that border deep and sometimes broad valleys.
The Spring Creek Watershed is bounded by Bald Eagle Mountain on the northwest and by Tussey Mountain and Nittany Mountain to the southeast (Figure 2).
Figure 2: Map of the Spring Creek Watershed. Click to open a larger PDF version.
The southwest boundary of the watershed is indistinct, because there is only a small elevation change when one moves southwest from the Spring Creek watershed into the Spruce Creek watershed. In contrast, to the northeast Spring Creek cuts through a narrow gap in Bald Eagle Mountain at Milesburg, where it flows into Bald Eagle Creek.
The Spring Creek watershed is comprised of 14 political subdivisions. Two boroughs, Bellefonte and State College, are located wholly within the watershed, while only parts of Milesburg and Centre Hall boroughs lie within watershed boundaries. Benner, College, and Patton townships lie within the watershed boundaries but only parts of Boggs, Ferguson, Halfmoon, Harris, Potter, Spring, and Walker townships are located in the Spring Creek watershed.
The Spring Creek watershed has a surface drainage area of 142 square miles, and it is comprised of six major sub-watersheds. The major sub-watersheds are Galbraith Gap Run, Cedar Run, Slab Cabin Run, Big Hollow, Buffalo Run, and Logan Branch. The groundwater drainage area of the Spring Creek Watershed is 175 square miles, which is 23% larger than the surface drainage area. To learn why the Spring Creek Watershed has two different drainage area, you can read the article: “Why two boundaries?”
The headwaters of Spring Creek are formed by springs in the valley floor near the southeast boundary. Galbraith Gap Run originates on Tussey Mountain and joins Spring Creek east of Boalsburg. At Oak Hall, Spring Creek is joined by Cedar Run, which is made up primarily of springs originating in the valley floor. From there, Spring Creek flows northwest, and downstream of Lemont it is joined by Slab Cabin Run, which is formed by several tributaries draining Tussey Mountain and some large springs, including Thompson Run. Owing to extensive development in the Slab Cabin Run basin and along East College Avenue, storm water runoff contributes substantial flow to Spring Creek during rainfall events.
The Big Hollow sub-watershed is extensively developed, yet owing to sinkholes and porous soils, storm water runoff from this basin rarely reaches Spring Creek. Rather, runoff leaves this basin as subsurface flow.
The Buffalo Run sub-watershed is a long, narrow basin that runs parallel to Bald Eagle Mountain. Buffalo Run originates near the Skytop Mountain Gap and flows 12 miles until it joins Spring Creek in Bellefonte. Logan Branch joins Spring Creek in Bellefonte upstream of the Buffalo Run confluence.Logan Branch originates on Nittany Mountain and is augmented by several large springs before flowing into Spring Creek, making it the largest tributary to Spring Creek.
Big Spring in Bellefonte is the second largest spring in the Commonwealth. It provides drinking water to the residents of Bellefonte and discharges 14.5 million gallons of water per day into Spring Creek.
At Milesburg, Spring Creek flows into Bald Eagle Creek, which flows northeast for 22 miles, where it enters the West Branch of the Susquehanna River at Lock Haven. From there the West Branch flows east to Williamsport and then south to Northumberland, joining the main stem of the Susquehanna River. The river continues south through Pennsylvania and Maryland, entering the Chesapeake Bay at Havre de Grace, Maryland.
The headwaters of the main stem Susquehanna River originate in Otsego Lake, New York, and the river flows 444 miles to the Chesapeake Bay. The Susquehanna River basin has a surface area of 27,510 square miles, about 80% of which is in Pennsylvania (Figure 3).
Figure 3: Map of the Chesapeake Bay Watershed. Click to open a larger PDF version.
The Susquehanna River basin supplies about one-half of all the freshwater entering the Chesapeake Bay including much of the sediment and nutrients that are adversely affecting the health of the Bay.
The Chesapeake Bay with a surface area of 4,480 square miles is the largest estuary in the United States. Its watershed covers an area of 64,328 square miles and contains a population of 17 million people. The Bay supports a diverse community of plants and animals represented by more than 36,000 species. Yet despite this remarkable ecological diversity, the Bay has some serious environmental problems.
Large areas of the Bay experience prolonged periods of little or no dissolved oxygen in the bottom waters; these anoxic regions are often referred to as dead zones because they do not support any plant or animal life. High levels of nutrients (nitrogen and phosphorus) entering the Bay stimulate excessive growth of algae. Dense algal masses in the surface waters prevent light from penetrating to the bottom, thus not allowing rooted aquatic vegetation to grow. As the algae dies, it sinks to the bottom and decomposing bacteria exhaust the dissolved oxygen. Finfishes, crabs, and shellfish cannot survive in water that is devoid of oxygen.
In recent years there have been some reductions in inputs of nutrients and sediment to Chesapeake Bay, but many more reductions are needed to bring the Bay back to its former productivity. Even though the Spring Creek watershed represents a tiny fraction of the Bay watershed, our inputs to the Bay matter. The Chesapeake Bay is a national treasure, and our watershed is one of its jewels.
Robert Carline is a fisheries biologist and the former leader of the U.S. Geological Survey’s Pennsylvania Cooperative Fish and Wildlife Research Unit at Penn State University
Graphics provided by D. Gilbert.