(Area Tributary to infiltration BMP)
(Base area of infiltration BMP)
|
*100%
|
Permeability Range1
(inches per hour)
|
Thickness Factor
|
---|---|
6.0 to 12.0
|
0.8
|
2.0 to 6.0
|
1.0
|
1.0 to 2.0
|
1.4
|
0.75 to 1.0
|
1.2
|
0.5 to 0.75
|
1.0
|
NOTES:
| |
1
|
If the permeability rate (as measured by the adopted 25 PA Code
§ 73.15, percolation test in Appendix G) falls on a break
between two thickness factors, the smaller thickness factor shall
be used.
|
Return Period
|
24-Hour Rainfall Depth
|
---|---|
1-year
|
2.64 inches
|
2-year
|
3.16 inches
|
5-year
|
3.91 inches
|
10-year
|
4.57 inches
|
25-year
|
5.60 inches
|
50-year
|
6.53 inches
|
100-year
|
7.63 inches
|
A graphical and tabular presentation of the Type II-24 hour
distribution is included in Appendix C of this chapter.[3]
|