This article was originally published by the Susquehanna River Basin Commission: State of the Susquehanna 2010 Report.
Spring Creek, a famous stream in the West Branch of the Susquehanna River watershed, is aptly named. Within this 146-square-mile watershed, there are at least seven springs that each produce more than 1 million gallons per day (mgd) of clean, cold water. These springs have influenced settlement patterns in the watershed. The most famous is Big Spring around which the Borough of Bellefonte was founded in 1795 (Figure 1). This is the second largest spring in the Commonwealth, with a production of 19 mgd.
In 1792, the flow from Thompson Spring was diverted to power the waterwheel at the Centre Iron Furnace in State College. Large springs in Pleasant Gap led to the establishment of the first trout hatchery in the watershed in 1903. A second hatchery was built in 1933 near large springs along Spring Creek in an area now known as Fisherman’s Paradise. And, Benner Spring, a few miles downstream of State College, became the site of a third fish hatchery in 1951. The number of prolific springs in the watershed is tied to the geology of the area.
The watershed, which lies within the Ridge and Valley Physiographic Province, is bordered by long, high ridges on the north and south with a broad valley in between. The ridges are comprised primarily of sandstone and some shales, while the valley is underlain by thick layers of limestone and dolomite. Sinkholes, which are common in the valley floor, are connected to dissolution cracks and caverns in the bedrock. These dissolution cavities provide a substantial storage capacity for groundwater, and are the source of many large springs.
The abundant sources of water fostered population growth along Spring Creek and its tributaries. In the early 1900s as many as 10,000 people lived in the Spring Creek watershed, yet there was not a single wastewater treatment facility. Human wastes were deposited in pit toilets or piped out of homes into streets, nearby streams and sinkholes. As a result, it is likely that water quality in Spring Creek and its tributaries was rather poor near population centers. To make matters worse, the State Correctional Institution at Rockview was completed in 1912 and it discharged raw sewage into Spring Creek.
Improvements in water quality began when the Pennsylvania State University built the first wastewater treatment plant in the watershed in 1913; the plant provided sewer service to campus and the borough of State College. Around 1920 the Correctional Institution built a wastewater treatment plant, and finally in 1939 Bellefonte built its first wastewater treatment plant. While these treatment plants reduced pollution, communities such as Lemont, Boalsburg, and Pine Grove Mills were still without sewer service.
After a long period of little growth, the population in the watershed grew rapidly after World War II. This growing population probably taxed the existing wastewater treatment plants and instances of fish kills became more prominent during the 1950’s. Between 1952 and 2005 there were at least 16 pollution incidents that killed 100 or more fish. While some of these fish kills were related to poorly treated wastewater, most were due to spills of toxic substances.
The most famous fish kill occurred in 1956 when sodium cyanide was dumped down the drain of a laboratory on the Penn State campus. After this poison passed through the University’s treatment plant, it entered a tributary of Spring Creek and then the main stem. The fish hatchery at Benner Spring withdrew water from the stream to supply its culture ponds and more than 147,000 trout perished when the sodium cyanide reached the culture ponds. It is not known how many wild fish died from this event. Several other spills between 1952 and 1972 killed thousands of fish. Fortunately, through time, the number and severity of toxic spills has decreased greatly, and fish kills are now rather rare events.
An important water quality milestone was achieved in 1969 when the University Area Joint Authority (UAJA) completed construction of a new wastewater treatment plant that took some of the waste load from the Penn State plant and provided service to several areas for the first time. The next milestone occurred in 1983 when the Penn State plant pumped all of its treated wastewater to a land treatment system, thereby totally eliminating its discharge to surface waters. In 1992 the Correctional Institution diverted all of its wastewater to the expanded treatment plant in Bellefonte; hence, its discharge to Spring Creek was eliminated. At present, only two wastewater treatment plants (UAJA and Bellefonte) are discharging into Spring Creek and both plants have adequate capacity along with advanced technologies to ensure a high quality of effluent.
For many years the water quality in Spring Creek was compromised by untreated or poorly treated wastewater. With the elimination of some discharges and the improved treatment of others, it is likely that water quality in Spring Creek today is better than it has been in the past century. Yet, despite these improvements, there are still signs of impairment to biological communities.
In the early 1990s, researchers at Penn State showed that reproduction of wild brown trout was being negatively affected by high sediment loads originating from agricultural land and urban runoff. Several community groups then began working with farmers to improve riparian conditions in two tributaries. As a result, the sediment load from these tributaries has been reduced by about 50%, and brown trout reproduction in the main stem of Spring Creek has improved. But, invertebrates living in the stream substrate indicate other environmental stressors.
In 2001 the Pennsylvania Department of Environmental Protection initiated a comprehensive examination of stream invertebrates in Spring Creek and its tributaries. A consistent result from these studies is that pollution-sensitive organisms decline downstream of large inputs of urban runoff. Analyses of storm water runoff do not indicate high concentrations of any single pollutant that could kill sensitive organisms. More likely, increases in sediment loads and small increases in several pollutants collectively affect these pollution intolerant invertebrates.
The history of water quality changes in the Spring Creek watershed is probably similar to many other communities in the Susquehanna River basin. Improved technology for treating municipal wastewater, more effective environmental laws, and aggressive enforcement have greatly reduced the negative impacts of wastewater discharges on stream water quality. At the same time, we have come to better understand how nonpoint source pollution affects water quality and biological communities. The challenge ahead is finding cost-effective ways to reduce nonpoint source pollution originating from agricultural lands and urban storm water.
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