_INSPECTION - C1982057 ‎(33)‎

• Permit No: C1982057
• IBM Index Class Name: INSPECTION
• Doc Name: Inspection Report
• Inspection Date: 10/14/2009
• Email Name: DTM
• Media Type: D
• Archive: No

III. 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.
shaped and riprapped. The channel extending approximately 600' upstream from the NE2
confluence exhibits steep sideslopes lacking riprap,with only scattered riprap or native spoil rock
along the bottom of the channel. Photo SL2-21 is a view upstream from near the lower end of the
reach; Photo SL2-22 is a more distant view downstream along the reach from an adjacent ridge.
Based on channel gradient and past performance, it is clear that the entire reach requires riprap
installation in accordance with Permit Figure 20-1.1. Due to the extent of grading and riprap
installation required,the 600 foot channel reach extending upstream from the 006-NE2
confluence will be excluded from the Division's SL-2 approval, and the work will need to
be properly completed during 2010.
A gully on the steep slope north of the channel, approximately midway along the reach, was
repaired with TRM installation in 2009 (Photo SL2-23). The upper end of the gully extends
uphill from the TRM section for over 200', with some downcutting 8-12"deep. Low impact
stabilization measures are warranted along this upper segment of the gully.
006 Gulch (Downstream of the 006-NE2 Confluence)
The 2006 inspection identified only relatively minor maintenance issues along this channel reach,
and the SL-2 inspection identified no concerns with channel construction or stability. Spoil
springs emerge along the channel near the upper end of this reach, and herbaceous vegetation
including wetland species is becoming well established in the riparian zone. Willows and
cottonwoods planted several years previously have not survived, however, likely due largely to
elk browsing. Photo SL2-24 shows the channel section upstream of the 006-SE1 confluence.
Channel 006-SI
This short channel segment through the reclaimed area extends from the southern "A"Pit
highwall reclamation area down to its confluence with 006 Gulch, a short distance to the west of
Stock Pond T-5. Both DRMS measurements from the 2006 inspection and SL-2 As Built cross-
sections indicate that the channel grade exceeds the design grade. Design grade depicted on
Exhibit 20-5.1 ranged from 4.6%to 8%, whereas As-Built profile shows grades ranging from 8-
12%, which is in the range measured by the Division for most of the channel length (11%). The
Division measured a short segment at the extreme upper end of the channel at 17%. Review of
pre-mine topography on Exhibit 7-6 indicates the slope of the original channel in the
approximate location of the reclaimed segment was in the 7%to 10%range, with some segments
up to 20%. The Postmine Channel Design Summary in the approved permit(Figure 20-1-1)
indicates that for 006-S1, a vegetated channel would be allowable for channel slopes up to 10%,
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