Stormwater Management

Historically within Pennsylvania, stormwater management design criteria were crafted by individual municipalities without consideration of watershed wide impacts. Adequate planning cannot be done on a parcel-by-parcel, municipality-by-municipality basis. Additionally, stormwater law was a patchwork of court decisions based partially on the civil law doctrine protecting downstream landowners and partially on the common enemy doctrine protecting the rights of upstream landowners. Lack of clear legal guidance and sufficient hydrologic information historically hampered the ability of municipalities to make sound stormwater management decisions. In 1978, the Pennsylvania General Assembly passed the Stormwater Management Act, Act 167 of 1978, which clarified both the technical and legal elements of stormwater management decisions.

Act 167 requires counties to prepare stormwater management plans on a watershed-by-watershed basis. The plans must be developed in consultation with the affected municipalities. Standards for control of runoff from new development are a required component of each plan and are based on a detailed hydrologic assessment. A key objective of each plan is to coordinate the stormwater management decisions of the watershed municipalities. Implementation of each plan is through mandatory municipal adoption of ordinance provisions consistent with the plan. Within Lehigh and Northampton counties, the Lehigh Valley Planning Commission prepares plans on behalf of both counties. The state has designated 16 Act 167 study areas within the region. Plans have been completed for each watershed to mitigate stormwater quantity and quality impacts of development activities.

To comply with requirements of the National Pollutant Discharge Elimination System (NPDES) regulations from the Environmental Protection Agency, most municipalities in Lehigh and Northampton counties must adopt and implement an ordinance that requires the use of stormwater Best Management Practices (BMPs) to reduce or prevent the discharge of pollutants into receiving waters. The Act 167 plans contain a model ordinance that, when adopted by the municipalities, meets the requirements under the federal program.