2019-09-18_PERMIT FILE - C1981035 ‎(9)‎

• Permit No: C1981035
• IBM Index Class Name: PERMIT FILE
• Doc Date: 9/18/2019
• Doc Name: Hydrologic Designs
• Section_Exhibit Name: KI Appendix 11
• Media Type: D
• Archive: No

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DESIGN CHARACTERISTICS FOR PIPES AND CHANNELS
Location Existing or
Required Required
Discharge Bed or
Invert Slope Diameter or Depth x
Side Slope x Width (ftj Discharge
Capacity
reach 10a re 'd i e 4.4 cfs 0.400 tra 1.5x2:1 x2 6.7 cfs
reach 11 existin i e < 6 cts 0.030 30" 30.9 cfs
reach 12 existing Swale 0.5 cfs 0.010 tri,0.3x10 2.2 cfs
reach 13 channel 0.5 cfis 0.041 tri, 1x1 4_g cfs
5.4 Channel Armor Design
Eastside Diversion Channel
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:
Colo. Dept of Highways:
bed dso = 12 inches
bank dso = 18 inches
bed dso = 10 inches
bank dso = 14 inches
As you can see the CDH technique results in a slightly tower dso that the Simons
and Sunturk method. Based on these results I recommend a bed dso = 1Z 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 dso d2o dso dao dso dso dso dso dso dtoo
dso=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 layershould 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
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January.I998 - .