Regulated Development Activity Table
| |||
---|---|---|---|
SWM Plan Requirement
|
New Impervious Area for New and Redevelopment
|
Disturbed Area*
|
Next Steps
|
Exempt
|
0
|
Less than 1 acre
|
Comply with exemption section of this chapter[1]
|
No-harm
|
Up to 1,000 square feet
|
Less than 3,000 square feet
|
Comply with no-harm section of this chapter[2]
|
Waiver/modification/demonstrated equivalency
|
Less than 1 acre, subject to municipal approval
|
Less than 1 acre
|
Comply with waiver/modification/demonstrated equivalency section
of this chapter[3]
|
Small project (per definition), refer to Appendix C[4]
|
1,000 square feet to 10,000 square feet
|
3,000 square feet to 20,000 square feet
|
Submit small project site plan complete with all attachments
|
Stormwater management plan meeting this chapter's requirements
|
Greater than 10,000 square feet if exempt and small project
criteria are not met, or if improvements do not meet no-harm criteria
|
Greater than 20,000 square feet
|
Consult a qualified professional
|
NOTES:
| |
*
|
The above table is only applicable for projects with earth disturbance
less than one acre and that have not had cumulative impacts, within
five years preceding the permit application date, that are in excess
of the square foot limits.
|
Acceptable Computation Methodologies for Stormwater Management
Plans
| ||
---|---|---|
Method
|
Developed By
|
Applicability
|
Win TR-20 (or commercial computer package based on TR-20)
|
USDA NRCS
|
Applicable where use of full hydrologic computer model is desirable
or necessary
|
Win TR-55 (or commercial computer package based on TR-55 i.e.,
VT/PSUHM)
|
USDA NRCS
|
Applicable for land development plans within limitations described
in TR-55
|
HEC-1, HEC-HMS
|
US Army Corps of Engineers
|
Applicable where use of full hydrologic computer model is desirable
or necessary
|
PennDOT 584 (based on Rational Method)
|
PennDOT
|
Applicable under standards established by PennDOT
|
EFH2
|
USDA NRCS
|
Applicable in agricultural areas subject to the program limits
|
SWMM
|
EPA
|
Applicable in urban and suburban areas subject to limits established
by EPA
|
PA DEP BMP Manual, 2006
|
PA DEP
|
Applicable under standards established by PA DEP
|
Other methods
|
Varies
|
Other methodologies approved by the municipality
|