Erosion and Sediment Pollution Control Program Manual.pdf

Channel #1 (Diversion Channel) on
WORKSHEET # 11
CHANNEL DESIGN DATA
CHANNEL OR CHANNEL SECTION DC-1A DC-1A DC-1A
Temporary or Permanent Temp Temp Temp
Design Storm 2-year 2-year 2-year
Acres 9.4 9.4 9.4
Multiplier (1.6, 2.25, or 2.75) 1.6 1.6 1.6
Qr (REQUIRED CAPACITY) CFS 15.0 15.0 15.0
Q (CALCULATED AT FLOW DEPTH d) CFS 15.0 17.4 14.8
PROTECTIVE LINING
Unlined
Curled
Wood
Mat
363-2134-008 / March 31, 2012 / Page 143
Tall
Fescue
Va (ALLOWABLE VELOCITY) FPS N/A 6.0 3
V (CALCULATED AT FLOW DEPTH d) FPS 6.3 4.4 2.7
a (MAX ALLOWABLE SHEAR STRESS) LB/FT 2
0.03 N/A N/A
d (SHEAR STRESS @ FLOW DEPTH d) LB/FT 2
0.87 N/A N/A
CHANNEL BOTTOM WIDTH (FT) 2.0 2.0 4.0
CHANNEL SIDE SLOPES (H:V) 2:1 2:1 2:1
D (TOTAL DEPTH) FT 1.2 1.5 1.5
CHANNEL TOP WIDTH @ D (FT) 6.8 8.0 9.8
d (CALCULATED FLOW DEPTH) FT 0.7 1.0 0.95
CHANNEL TOP WIDTH @ FLOW DEPTH d (FT) 4.8 6.0 7.8
BOTTOM WIDTH: FLOW DEPTH RATIO (12:1
MAX)
d50 STONE SIZE (IN) N/A N/A N/A
A (CROSS-SECTIONAL AREA IN SQ. FT.) 2.38 4.0 5.61
n (MANNING’S COEFFICIENT) 0.02 0.035 0.06
R (HYDRAULIC RADIUS) 0.46 0.62 0.68
S (BED SLOPE, FT/FT) 0.02 0.02 0.02
Sc (CRITICAL SLOPE) 0.008 0.023 0.063
.7Sc 0.006 0.016 0.044
1.3Sc 0.010 0.016 0.082
STABLE FLOW? (Y/N) Y N Y
FREEBOARD BASED ON UNSTABLE FLOW FT N/A 0.3 N/A
FREEBOARD BASED ON STABLE FLOW FT 0.2 N/A 0.5
MINIMUM REQUIRED FREEBOARD FT
DESIGN METHOD FOR PROTECTIVE LINING
0.5 0.5 0.5
PERMISSIBLE VELOCITY (V) OR SHEAR
STRESS (S)
S V V
2.9
2.0
4.2