Return Interval
(year)
|
24-hour Rainfall Total
(inches)
|
---|---|
1
|
2.40
|
2
|
2.90
|
10
|
4.36
|
25
|
5.43
|
50
|
6.38
|
100
|
7.48
|
Where:
| |||
Tlag
|
=
|
Lag time (hours).
| |
L
|
=
|
Hydraulic length of watershed (feet).
| |
Y
|
=
|
Average overland slope of watershed (percent).
| |
S
|
=
|
Maximum retention in watershed as defined by: S = [(1,000/CN)
- 10].
| |
CN
|
=
|
NRCS Curve Number for watershed as defined by the NRCS Loss
Method.
|