Post-Construction Site Runoff Control

Once construction is completed, the MS4 General Permit requires York County to develop, implement, and enforce a program to address permanent stormwater discharges after construction from new development and redevelopment sites where the land disturbance is greater than or equal to one (1.0) acre to the MS4 (including projects that disturb less than one (1.0) acre that are part of a larger common plan of development or sale).  The regulations also require that York County ensure that control measures are installed and implemented that prevent or minimize water quality impacts.

As part of these requirements, the York County is required to:

• Develop and implement approaches to address post-construction stormwater discharges that include a combination of structural and/or non-structural controls;
• Adopt adequate legal authority to enable York County to address post-construction stormwater discharges from new development and redeveloped sites; and
• Ensure adequate long-term operation and maintenance of applicable post-construction control measures.

This component of the York County SWMP is designed to provide York County the authority to require structural and non-structural stormwater management facilities or best management practices (BMPs) on construction sites for permanent use.  This program holds owners responsible for the operation and maintenance of permanent stormwater management facilities or BMPs through a legal document described as the Covenant for Permanent Stormwater System Maintenance and Responsibility. It also provides York County the authority to conduct post-construction site inspections and the ability to enforce violations. The post-construction BMPs along with inspection and enforcement are expected to provide continued, long-term, reduction in siltation, turbidity, and other pollutants associated with developments.