Erosion and Sediment Pollution Control Program Manual.pdf

STANDARD E&S WORKSHEET # 9
Time of Concentration
PROJECT NAME:
LOCATION:
PREPARED BY: DATE:
CHECKED BY: DATE:
PATH
NUMBER
LENGTH
L (FT)
PATH
NUMBER LENGTH (FT)
PATH LENGTH
NUMBER (ft)
PATH
NUMBER
AREA
(sq. ft.)
BOTTOM
WIDTH (ft)
“n”
VALUE
AVG.
SLOPE
(S)
(ft/ft)
OVERLAND FLOW:
AVERAGE
SLOPE (S)
(ft/ft)
TIME
(minutes)
SHALLOW CONCENTRATED FLOW:
TYPE
OF
COVER
WET’D
PERIM
(ft)
LEFT SIDE
SLOPE (H:V)
AVERAGE
SLOPE(S)
(ft/ft)
CHANNEL FLOW:
HYDR.
RADIUS
(ft)
MANNING’S
“n”
CHANNEL DIMENSIONS:
RIGHT SIDE
SLOPE (H:V)
Tc ( sheet flow)
V
(ft/sec)
V
(ft/sec)
TOTAL
DEPTH (ft)
363-2134-008 / March 31, 2012 / Page 380
2 L ( n)
3 S
0..
5
n Type of Cover
0.02 smooth pavement
0.1 bare parched soil
0.3 poor grass cover
0.4 average grass cover
0.8 dense grass cover
(L = 150’ maximum)
TIME
(minutes)
CHANNEL
TIME
(minutes)
TOP WIDTH
(ft)
0.
4673
TC
(minutes)