Developing an Integrated Sediment TMDL Compliance Strategy through Interjurisdictional Collaboration

Three jurisdictions, comprising 98 percent of the Paxton Creek watershed in and near Harrisburg, PA, collaborated on a watershed-wide compliance strategy to achieve a TMDL for sediment, a requirement of Pennsylvania's Small Municipal Separate Storm Sewer System (MS4) NPDES Permit. Over 85 percent of the sediment load is attributed to in-stream erosion, causing habitat degradation in 40 percent of Paxton Creek and threatening property, roadways, and infrastructure adjacent to the Creek. The strategy involves in-stream restoration measures to address erosion, flooding, and threatened infrastructure; land-based control of accelerated flows/pollutant loads (including implementation of a comprehensive CSO LTCP), and policies to prevent further degradation. Early action projects are proposed to illustrate control measures while more detailed planning further quantifies control requirements and costs.