_INSPECTION - C1994082 (67) - Laserfiche WebLink

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Ill. 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. ridgeline is directed away from the slide and through the straw wattles. Detailed observations were made difficult by the snow cover, and the area will need to be closely checked by the operator following melt, to ensure that any necessary maintenance is promptly completed. In a couple locations along the north perimeter of the disturbance, it appeared that straw wattle segments oriented east/west would be appropriate, where small areas might drain to the north rather than to the west. Also, the soil stockpile berm was worn down in one location along the NW perimeter of the stockpile, and needs to be built back up. Field modifications to the plan may be warranted during slide remediation operations later this year.Wattles will need to be removed from areas that will be directly impacted by remedial grading, and placed as necessary to ensure that any runoff that drains offsite will pass through a series of wattles. Pond 11 was inspected on the morning of April 30. There had been another inch of fresh snow accumulation overnight. The pond was full to the level of the primary spillway, with a trickle of clear discharge. The embankment appeared stable, although details were obscured by several inches of fresh snow cover. Backfill and Grading Ground conditions and snow cover limited access and prevented detailed observations, however the following observations were made: • Side-scour was evident on Channel PM 3-2, approximately 150 yards downstream of the riparian tree/shrub plot, maintenance is warranted. • A circuitous gully up to 2'deep and approximately 150 feet in length was observed on the roughened/revegetated slope in the extreme southwest corner of the reclaimed Pond 14 watershed. The gully extends down-slope to undisturbed aspen woodland above Pond 14, approximately 50 yards north of the south disturbance perimeter. Repair in accordance with the approved Rill and Gully plan is warranted. • The length of temporary Diversion 14A was walked. The diversion appears to be stable, intact and functional. The diversion intercepts disturbed runoff from the southern perimeter of the reclamation in the Sage Creek watershed, and directs the runoff to a natural drainage further north,which routes the runoff into Pond 14 (see permit Exhibit 13-12.1). Diversion 14A was erroneously included by the operator in Phase 1 bond release application SL-2. Inclusion of the diversion acreage in the Phase 1 release request was inappropriate, because the diversion is temporary; it is not an approved permanent drainage feature, and will need to be removed upon approval by the Division in accordance with Rule 4.05.2(2). The Division will exclude Diversion 14A from the proposed approval decision for Phase 1 Bond Release SL-2. • The repaired slide slope in the upper Pond 13 watershed was observed. Slope of the repaired slide was measured with an inclinometer to be approximately 26%. The slope was moderately roughened and seeded on the contour last fall. There is no apparent evidence of further movement or erosion. The annual cover crop included with the seedmix had recently germinated and leaves were poking through the 1-2" snow cover on the slope. • Condition of the Pond 12 slide area appears to be unchanged from conditions described in recent inspections. The Division issued a proposed decision to approve Technical Revision#46 (TR-46)on May 7, 2010. TR-46 presented remediation plans for the slide area, to be implemented during the 2010 field season, upon final approval of the revision. Remediation will involve final drainage construction in the lower Pond 12 watershed, incorporation of graveled drainage trenches, and regrading of the slide affected slope. The slope will be cut back into competent rock,with unconsolidated material removed from the cut slope to be excavated along the existing scarp zone. 4