The PennDOT Bureau of Project Delivery’s Antidegradation and Post-Construction Stormwater Management Policy is the first comprehensive stormwater policy adopted by PennDOT. NTM Engineering assisted the Bureau of Project Delivery’s Highway Quality Assurance Division with developing and writing this Policy.
When the Pennsylvania Department of Environmental Protection developed its 2006 Pennsylvania Stormwater BMP Manual, it became apparent that the recommended guidance for addressing stormwater runoff was heading in a direction not necessarily congruent with highway applications. Foreseeing potential design and permitting issues, PennDOT took action to develop its own policy and guidance. PennDOT’s Antidegradation and Post-Construction Stormwater Management Policy defines how PennDOT will achieve compliance with antidegradation laws related to stormwater management. It sets parameters for handling post-construction runoff for various project categories based upon typical amounts of new impervious area construction and the potential for impacting sensitive areas. NTM’s task of developing and writing the Policy required extensive research of state and federal regulations related to stormwater discharges to surface waters and antidegradation laws. NTM consulted manuals and technical guidance from other state Departments of Transportation and environmental agencies to determine the most appropriate stormwater best management practices (BMPs) for PennDOT’s highway facilities. NTM also coordinated regular meetings with the Pennsylvania Department of Environmental Protection that enabled key personnel to collaborate on a Policy consistent with Pennsylvania’s environmental and highway programs.
In 2014, PennDOT requested that NTM prepare a major update to the Policy to address regulatory changes and incorporate advances in stormwater research and technologies. The firm is currently working on this update.