Characterizing Water Quality and Effectiveness of a Constructed Wetland/Pond System to Remediate Nutrient Loads in a Carbonate Spring in South Central Pennsylvania

Abstract

Nutrient loading is a common environmental problem in spring-fed streams and freshwater ponds. Nitrates and phosphates are easily transported in carbonate springs and are also introduced into ponds via runoff from agricultural sources as well as directly from animal waste from both livestock and wildlife. Due to their natural solubility, nitrates and phosphates can accumulate in groundwater and when brought to the surface they can cause major environmental consequences to downstream ecology such as eutrophication, algal blooms, and hypoxia. Dykeman Spring is an example of an impacted karst-fed spring and stream in the Shippensburg, Pennsylvania region and is the focus of this study. This spring functioned as a public water supply for over 100 years, but due to an evaluation deeming it groundwater under influence (GWUI), an order to remove the spring from service was issued by Pennsylvania DEP in 1999. Current water quality of this system is unknown, as is the functional value of an adjacent constructed wetland where a portion of the waters are diverted before returning back to Branch Creek. 

The research goals for this study are ultimately to: A) determine the current water quality (i.e. temp, DO, pH, specific conductivity, nitrate, and phosphate) emanating from the spring head and at key locations downstream, B) characterize the wetland’s ability to remove/retain pollutant loads and improve water quality seasonally, C) better understand the hydrological network by evaluating source areas and their potential for nutrient loading or other contaminant introduction into Dykeman Spring, and D) provide a dataset that will lay the foundation for developing future mitigative measures to enhance water quality in the Dykeman Spring/Branch Creek watershed. Information and analyses developed through this research will help area stakeholders including the Borough of Shippensburg make decisions regarding future environmental resource management of the Dykeman Spring and Branch Creek wetland for improvements to green infrastructure.