2004-10-13_REVISION - M1978116

• Permit No: M1978116
• IBM Index Class Name: Revision
• Doc Date: 10/13/2004
• Doc Name: Responses to Questions of PAR
• From: Cotter Corporation
• To: DMG
• Type & Sequence: AM1
• Media Type: D
• Archive: No

~ p p. >4 .
~Vorlcsileet 3: 'Time of concentration ('I`~) or travel time (Tt)
Pro jec[ i.Jr/ '~ /"f /rt2 By ~_~ Dace /0-6 -o'f
Location Uy $fr-e 4 M Checked Da [e
-T
Ctrc le one: resent Developed
Circle one: T~ Tt through subarea SLG~ 4i-eQ 1 1 d 2,
NOTES: Space for as many as two segments per flow type can be used for each
worksheet.
include map, schematic, or description of flow segments.
Sct( ! Snd Z
Sheet flow (Applicable to Tc only) Segment ID
1. Surface description (table 3-1) ............
2. Manning's roughness coeff., n (table 3-1) ,.
3. Flow length, L (total L < 300 ft) .......... ft
4. Two-yr 24 -lir rainfall, P2 .................. in
5. Land slope, s .............................. ft/ft
6. Tt = O.D075(nL0 )~'8 Compute TC ,,,... hr
P2 s
Shallow concentra [ed flow Segment ID
7. Surface description (paved or unpaved) .....
8, Flow length, L ............................. ft
9. Watercourse slope, s ....................... ft/ft
10. Average ve loc£ty, V (figure 3-1) ........... f[/s
11. Tt 3600 V Compute Tt ...... hr
Channel flow Segment ID
12. Cross sectional flow area, a ............... fc2
13. Wetted perimeter, p ....................... f[
w
14. Hydraulic ra dlus, r = Pa Compute r ....... ft
w
15. Channel slope, s ........................... ft/f[

E} ~ ~ /f - l3
//,~
J14R n
R4R Q
0,/3 0./3
Z$0 ZQO
I. l 1.1
D•l5 O•ZS

$-C 8-C
unP4ve~ unp4ved
SS° li.Do
O.13 D•/7
s,s 6.7
o•aze D.os°
_~
16. lda nning"s roughness coeff., n ..............
213 1/2
17. V = 1.49 r s Compute V ....... f[/s
n
18. Flow length, L ............................. f[
19. T[ 3600 v Compute Tt ,..... hr + _
20. Wace rs hed or subarea To or Tt (add Tt in steps 6, 11, and 19) ....... hr o•z79 D ZS~
skd / S.,b Z