The Pennsylvania Department of Environmental Protection (“DEP”) has proposed a number of significant changes to its Post-Construction Stormwater Management (“PCSM”) Manual. PCSM requirements potentially impact construction projects across the Commonwealth, especially those involving land disturbances of greater than one acre. The purpose of DEP’s manual is to provide guidance on 1) the development of PCSM plans for earth disturbance activities under the Department’s regulations relating to erosion and sediment control; 2) the design, installation, and operation and maintenance of post-construction stormwater control measures; and 3) the completion of a stormwater analysis to protect surface waters of this Commonwealth. 

The substantial revisions that are proposed by DEP in the draft Pennsylvania PCSM Manual are summarized as follows:

• New interpretive guidance on the PCSM regulations (25 Pa. Code § 102.8 (relating to PCSM requirements)).
• A proposed hierarchy of stormwater management objectives.
• Additional detailed information on the performance of the stormwater analysis that is required for PCSM at 25 Pa. Code § 102.8(g), including the addition of new methodologies for the analysis of volume, water quality and rate management.
• Proposed criteria for the protection of wetlands.
• New best management practices—which are referred to in the draft Pennsylvania PCSM Manual as stormwater control measures (SCM)—including, but not limited to, managed release concept SCMs.
• New incentives for the protection of natural open spaces and natural stormwater features.
• New methods for the completion of the pre-development site characterization required by the regulations, including infiltration testing.
• Introduction of methods for adjusting precipitation depths for stormwater analysis based on the known effects of climate change.
• New guidance regarding: antidegradation requirements; the determination of discharge points and points of analysis; analyses of stream stability and erosion potential; off-site stormwater management; the evaluation of thermal impacts; and the assessment of projects located in areas of karst geology.

Interested persons may submit written comments on this draft document through Friday, April 28, 2023. Commentators are encouraged to submit comments using the Department’s online comment tool at www.ahs.dep.pa.gov/eComment. Copies of the document can be obtained from DEP by contacting Sean Furjanic, PE, at sefurjanic@pa.gov.

If you have any questions about the proposed changes to the DEP’s Post Construction Stormwater Management Policy, please contact me or anyone in the Barley Snyder Environment & Energy Industry Group, Real Estate Practice Group or the Construction Industry Group.