Post-restoration changes within Codorus Creek, south-central Pennsylvania

Penn State University (York and Harrisburg campuses) has been evaluating the effectiveness of state-funded stream restoration activities. Research has been performed on two branches of Codorus Creek, located in south-central Pennsylvania. This current research presents only the data obtained at Penn State Harrisburg. We examine the current pollutant loadings of two branches of this stream in conjunction with land use practices. Macroinvertebrates and periphyton are sampled routinely. Streamwater sampling for water chemistry analyses occurs during both baseflow and storm event conditions. Restored sites are compared to both impaired and control sites to determine whether restoration has any significant reduction in a pollutant's load. All sources contributing to the total nitrogen load to Codorus Creek have not been identified. Although restoration activities may decrease pollutant loads, such as suspended solids, restoration is not believed to be effective in decreasing nitrogen loads. Nitrogen is found more readily in the aqueous phase (streamwater) rather than adsorbed to sediment particles. Therefore, more effective ways to remove nitrogen in water is to decrease or eliminate the source or to treat the streamwater directly. Further monitoring and comparison of restored sites to control and impaired sites are needed. In addition, future work on the toxicity of the legacy sediments has been proposed.