PERMFILE56263

• Permit No: C1981008A
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Section_Exhibit Name: NH1 TAB 13 ATTACHMENT C SEDIMENTATION POND 002
• Media Type: D
• Archive: Yes

• Two different ditch sections are proposed far the diversion ditch based
on the critical slope calculation of the ditch section. One ditch
section will be constructed with riprap and the other section without
riprap, depending on whether the ditch's slope is steeper or flatter
than the critical slope of 1.B percent. A summary of the ditch design
for the North Ditch is listed below (see Exhibit 13-13).
Ditch Factor North Ditch
Q 3.45 cfs
Z 2:1
Shape V-ditch
Alternate A (without riprap) 0.025
Alternate B (with riprap) 0.040
d (critical) 0.71 ft.
S (critical) 1.5%
V (critical) 3.39 fps
Based on the above results, the North Ditch of Pond No. 002 will be
constructed with the following minimum dimensions (see Exhibit 13-13).

Alternate A (without ripra
Minimum depth = 2.0 ft.
Side Slopes = 2H:1V
Slope = 0% to 1.5%
Maximum Velocity = 3.39 fps
Q = 3.45 cfs
Manning's N = 0.025
Shape = V-ditch
Alternate B (with riprap) :
Minimum depth = 2.0 ft.
Side Slopes = 2H:1V
Ditch Slope = 1.3% to 50%
Maximum Velocity = 8.93 fps
Q ~ = 3.45 cfs
Manning's N = 0.040
• Shape = V-ditch
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