PERMFILE63825

• Permit No: C1981035A
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Doc Name: MODIFICATION A
• Section_Exhibit Name: APPENDIX 8 HYDROLOGIC DESIGNS
• Media Type: D
• Archive: Yes

DESIGN CHARACTERISTICS FOR PIPES AND CHANNELS
Location Existing or
Required Required
Discharge Bed or
Invert Slope Diameter or Depth x
Side Slope x Width (ft) Discharge
Capacity
reach 10a re 'd i e 4.4 ds 0.400 tra 1.5x2 1x2 6.7 cfs
reach 11 existin i e < 6 ds 0 030 30" 30.9 ds
reach 12 existing swale 0.5 cfs 0 010 tri,0.3x10 2.2 cfs
reach 13 channel 0.5 Cs 0.041 tri, 1x1 4.9 ds
5.4 Channel Armor Design
Eastside Diversion Channef
The sizing of riprap for the eastside drainage channel was completed using two
methods. The first is a stability analysis technique proposed by Simons and Sunturk
(see attached worksheet); the second is a procedure used by the Colorado Department
of Highways and outlined in "Roadway Design Manual" 1990. The results are as follows.
Simons and Sunturk: bed dso = 12 inches
bank dso = 18 inches
Colo. Dept of Highways: bed dso = 10 inches
• bank dso = 14 inches
•
As you can see the CDH technique results in a slightly lower dso that the Simons
and Sunturk method. Based on these results I recommend a bed dso = 12 inches and a
bank dso = 14-18 inches. These sizes are based on a side slope of 2:1 which is a
recommended minimum for scouring channels. The gradation for the riprap mixture
should be as indicated below.
size in d1o dzo dw d4o dso dso dso dao I d9o dtoo
dsa=12, 14' S 7 9 11 14 16 19 21 25 26
dso=18" 7 9 12 14 18 21 24 27 32 36
The thickness of the riprap layer should be at least 1.5 times the dso dimension.
Standard construction practices, including base preparation and well graded base
material should be followed.
Channels Down the Face of Pile
Both channels down the face of the waste pile require armoring. Application of the
rip-rap stability analysis technique, used above, resulted in a Dso= 36 inches (factor of
9
January 1998