PERMFILE138126

• Permit No: C1991078A
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Section_Exhibit Name: Exhibit 09 Protection of the Hydrologic Balance
• Media Type: D
• Archive: Yes

•
DITCH.WIil EXHIBIT 9
HAUL ROAD DRAINAOE
The haul road culvert is to be placed in the dry wash
between mining areas No. 1 & 2. This culvert receives run-off
from a portion of drainage Area E. The size of the borrow
ditches is checked below. For calculation purposes it is
assumed that each ditch will receive run-off from the 50' width
of the roadway. With relief drains every 1000', the ditch
drainage area is 1.1 acres.
PEAK FLOW CALCULATION
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DRAINAGE AREA (ACRES)
CURVE NO.
STORM EVENT _1'R. , 24 HR.
STORM EVENT in.
RUNOFF in.
WATERSHED RELIEF ft.
Lc 25 ft.
Lc 50 ft.
Lc 75 ft.
WATERSHED SLOPE
SLOPE ADJUSTMENT FACTOR
LENGHT OF WATERSHED
EQUIVALENT DRAINAGE AREA
PEAK FLOW cfs/in Fig D-2
ADJUSTED PEAK FLOW
BORROW
CULVERT 1 DITCHES
46.4 1.1
80 90
10 10
1.6 1.6
0.34 0.76
90
1375
1350
1600
4.8 6.00 MAXIMUM
1.03 MODERATE 1.07
2600 1000
67 14
50 18
12.03 1.23
Use a 24" diameter CMP or equivalent to handle the 12 cfs flow.
Place rip rap at outlet and inlet of CMP to prevent downcutting
HAUL ROAD BORROW DITCHES
FLOW IN A TRIANGULAR CHANNEL - 1% SLOPE
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ENTER DEPTH D 0.600 FEET
ENTER SLOPE S 0.010 EXPRESS AS DECIMAL
ENTER "N" N 0.030 EXPRESS AS DECIMAL
ENTER SIDE SLOPE X 2.000 SLOPE = X: 1
AREA=(W*D)+(X*D"2)= 0.72 FEET"2
WETTED PERIMETER=(W)+2((XD"2+D"2))".5 2.68 FEET
R=AREA/WETTED PERMITER 0.27
V=(1.49/N)*(R".667)*(S".5)= 2.07 FEET/SEC
Q = A X V = 1.49 CFS
Q REQUIRED 1.23
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