Pennsylvania

Pennsylvania Post-Construction Stormwater Management (PCSM) Manual

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Open source PDF ↗Official agency page ↗

Other manuals in Pennsylvania: Philadelphia

Document Metadata

Jurisdiction level

state

“DEPARTMENT OF ENVIRONMENTAL PROTECTION Bureau of Clean Water”
Page i

State

Pennsylvania

“Pennsylvania Department of Environmental Protection 400 Market Street, P.O. Box 8774 Harrisburg, PA 17105-8774”
Page ii

Version / edition

January 28, 2023 / DRAFT

“386-0300-001 / January 28, 2023 / DRAFT”
Page i

Adoption / effective date

Not found in document

“EFFECTIVE DATE: Upon publication of notice as final in the Pennsylvania Bulletin.”
Page i

Last revised date

2023-01-28

“386-0300-001 / January 28, 2023 / DRAFT”
Page i

Relationship to state manual

independent

“This Pennsylvania Post-Construction Stormwater Management Manual (PCSM Manual or Manual) was developed to update and replace the Pennsylvania Stormwater Best Management Practices Manual (363-0300-002) that was published by the Pennsylvania Department of Environmental Protection (DEP) in December 2006”
Page 1-1

Design Criteria

Design storm return periods (years)

2-year, 10-year, 50-year, 100-year

“manage the net change in peak rate for the 2-, 10-, 50-, and 100-year/24-hour storm events in a manner not to exceed preconstruction rates”
Page 2-37

Water quality volume method

A pollutant load approach, coupling volume and water quality management, in which statistically derived land cover-based pollutant concentrations are applied to runoff, volume reductions through SCMs are taken into account, and post-construction pollutant loads are compared to pre-construction pollutant loads.

“Water quality is addressed in this Manual through a pollutant load approach, coupling volume and WQM. First, statistically derived land cover-based pollutant concentrations are applied to runoff from existing and proposed site conditions. Second, volume reductions through SCMs are taken into account. Finally, post-construction pollutant loads are evaluated based on SCM effluent (outflow) pollutant concentration data from accepted data sources such as the National Stormwater Quality Database and the International Stormwater BMP Database, and compared to pre-construction pollutant loads.”
Page 1-18

Peak flow calculation method(s)

NRCS hydrologic soil-cover complex method, Green and Ampt equation, Snyder Unit Hydrograph, WINSLAMM small storm hydrology method, nonlinear reservoir runoff, kinematic wave methods

“Methods include the NRCS hydrologic soil-cover complex method, Green and Ampt equation, Snyder Unit Hydrograph, and WINSLAMM small storm hydrology method.”
Page 2-53

Required hydrologic/hydraulic software

HEC-RAS, iRIC, EPA SWMM

“HEC-RAS, International River Interface Cooperative (iRIC), or other software capable of performing a sediment transport analysis.”
Page 2-65

Approved BMP categories

Protect and Preserve Natural Landscape Processes, Enhanced Natural Landscape SCMs, Infiltration-Based SCMs, Non-Infiltration SCMs, Managed Release Concept, Rate Control SCMs

“A.1 Protect and Preserve Natural Landscape Processes A.2 Enhanced Natural Landscape SCMs B.1 Infiltration-Based SCMs B.2 Non-Infiltration SCMs Managed Release Concept Rate Control SCMs”
Page 3-4, Table 3-1