INSPEC26917

• Permit No: C1982057
• IBM Index Class Name: Inspection
• Doc Name: Inspection Report
• Inspection Date: 6/29/2006
• Media Type: D
• Archive: No

111. COMMENTS -COMPLIANCE
Below are comments on the inspection. The comments include discussion of observations made
during the inspection. Comments also describe any enforcement actions taken during the inspection
and the facts or evidence supporting the enforcement action.
C to EE (006-NE2 confluence down to 006-SE1 confluence)
Design profile depicts a low gradient segment, averaging less than 5% grade for the entire length.
Design specification for channel segments with gradient less than 5% is trapezoid channe! with 5'
bottom width, 2.1' depth, 17.6' top width, vegetated channel. For channel segments with grade between
6% and 11 %, specification is 5' bottom width, 0.9' depth, 10.4' top width, riprap D50 6".
Channel gradient appears to conform with approved profile, with short, riprapped steep
segments (approximately 10% grade), alternating with longer low gradient (less than 5% grade)
segments that are not riprapped. Upper section is a wide, low gradient channel generally
conforming to the approved design, however the channel has agravel/spoil substrate and is
generally not vegetated. A meandering channel approximately 12" deep by 4' wide has
developed inside the larger channel. Operator has recently planted willows and cottonwoods
along this segment. Most of the cottonwoods and some of the willows have been severely
browsed; pulled up, or otherwise damaged by elk. Vegetation establishment along the channel
may not be likely until upper sections of the watershed are stabilized. Establishment of
cottonwoods and other trees and shrubs attractive to elk may require fencing. Canada thistle is
particularly thick adjacent to the channel along this reach and will need to be sprayed.
• A 10% gradient segment further downstream exceeds design width and depth, and was properly
riprapped and stable. Further down, another non-riprapped low gradient segment, similar in
appearance to upper low gradient segment; trees planted here as well, with fair to good survival
of willows but cottonwoods heavily damaged by elk. Lower-most segment down to SE1
confluence is higher gradient, properly riprapped and stable. There are some hillslope gullies
that enter the channel from the east along this lower reach, which will need to be repaired.
EE to 88 (006-SE1 confluence down to CMP A-1 Inlet)
Design profile depicts a relatively low gradient segment averaging 6.1 %. Design specification for 5% to
8% gradient is trapezoid channel with 5' bottom width, 1.1' depth, 11.6' top width, 6" riprap.
• Channel gradient and dimensions appear to be within design limits along the length of the
segment, however there is one 100'+ section along the upper end where flow has concentrated
along the outside of the riprap and has cut into the bank, resulting in a vertical cut approximately
2 feet high (Digital Image 2578). Minor grading and riprap maintenance is warranted.
006-51 Channel
This short channel extends from the southern "A" Pit highwall reclamation area down to 006 Gulch,
running along the west edge of the fenced planting area near Stock Pond T-5. Design profile shows
average gradient of 8% along the upper segment, decreasing to 4.6% at the lower end. Figure 20-1.1
designs specify a "V" shaped vegetated channel 1.9' deep and 11.4' wide for gradients up to 10%;
trapezoid channel with 2' bottom width, 0.6' depth, 5.6' top width, and 6" D50 riprap for segments
between 11 % and 16% grade.
Channel Gradient appears to be significantly steeper than indicated on design profile.
Lower section (200'+/-) was measured at 11% slope, compared to 4.6% indicated on
design. A short upper section was measured at 17% grade, compared to 8% indicated on
design. This apparent discrepancy will be evaluated in the context of the Phase 1 bond
release application that was recently submitted. Digital Image 2581 is view from upper end
of channel in vicinity of Design Point XX, toward the confluence with 006 Gulch.
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