2008-01-28_PERMIT FILE - C1992080A

• Permit No: C1992080A
• IBM Index Class Name: Permit File
• Doc Date: 1/28/2008
• Section_Exhibit Name: APPENDIX 5-2 SEDIMENT POND CONTROL DESIGN
• Media Type: D
• Archive: Yes

•
Sediment Pond l/1
Method 1 - Peak Flov Doing Te vs. CSM Charts:
Page 5 of 7
Hote: Time of concentration (Tc) may be computed using either travel
time or leg ac shove below. (There are other methods used to
obtain ie which may be preferred over the once show below.)
A• Computation of Tc Using Travel Time
Tc -Length of Segment (Li) _ - Ll + L2 + L; + ...Ln x 1 ~ Hrs.
Velocity Through Segment (VS) Vl V2 D; an 3600
LI-Ft. 0i-Ft/See.
E. Computation of Tc Using Iag 1/
Slope Data: Watershed Height (z) -
Contour Length (LC25) - -ft. X255 of (z)
Contour Length (LCSD) - ft. @SOS of (;)
Contour Length (LC75) ~ ft. @75x of (z)
Drainage Area (DA) - "~q ft.
•
.25z(LC25 + LCS~ + LC75)
slope - x
DA (sq. ft.)
Aydreulic Length or Flov Length -
Slope Y.ydraulie Soll Cover Lag Tc (hr)
(y,) Length
(f t) Com lex r!o.
P
(Equation 3.2) from

(1)
2
(3)
4 Figure 6
3640 87 0.13
C. Peak Flov

Tt
(hr)
1 Peak Discharge
cfs/in./sq.mi.)
(FS S-1)
2
Total Area
(s q. mi.)
(3) Storm
requency
(yr.)
(4)
punoff
(in.)
5 Total Peak
Discharge (cfs)
(Col. 2x3x5)
O.lr 830 0.07 10 1.07 62.17

1/ Intended for watersheds in their natural condition. Zf Significant
urbl'n areas exist use Page 4 for modification.
loot - x
3640 ft.