Table 403-1 Control Criteria for Stormwater
Management Districts
| ||
---|---|---|
District
|
Control Criteria
| |
100%
|
Postdevelopment peak discharge for all design
storms must be no greater than predevelopment peak discharges.
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75%
|
Postdevelopment peak discharge for all design
storms must be no greater than 75% of the predevlopment peak discharges.
| |
50%
|
Postdevelopment peak discharge for all design
storms must be no greater than 50% of the predevelopment peak discharge.
| |
SOURCE: Gannett Fleming, 2001
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Table 405-1
Acceptable Computation Methodologies
for Stormwater Management Plans
| |||
---|---|---|---|
Method
|
Method Developed By
|
Applicability
| |
TR-20 or commercial package based on TR-20
|
USDA - NRCS
|
When use of full model is desirable or necessary
| |
TR-55 or commercial package based on TR-55
|
USDA - NRCS
|
Applicable for plans within the model's limitations
| |
HEC-HMS
|
U.S. Army Corps of Engineers
|
When use of full model is desirable or necessary
| |
PSRM
|
Penn State University
|
When use of full model is desirable or necessary
| |
Rational Method or commercial package based
on Rational Method*
|
Emil Kuiching (1889)
|
For sites with a total contributing drainage
area of less than 100 acres
| |
Rational Method or other methods
|
Various
|
As approved by the Township Engineer
|
*Use of the Rational Method to estimate peak
discharges from drainage areas that contain more than 100 acres must
be approved by the Township Engineer.
| |||
SOURCE: Gannett Fleming, 2001
|