_INSPECTION - C1982057 (61) - Laserfiche WebLink

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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. Tie Across Haul Road • Ditches, culverts, and ditch relief drains were generally in good condition. One exception is that a section of TAHRD-22, along the outside road bend in the vicinity of Sta. 205+00 has incised approximately 12-18", and riprap installation is warranted. Road"J"(Reduced for Postmining Land Use) Road "J" had only recently dried sufficiently for vehicle access and maintenance work has not yet been initiated. Typical spring maintenance grading is warranted along the road. The following specific maintenance issues were noted: • Minor erosion around and beneath large boulders at J-2 culvert outlet, with rilling extending 30' down to silt fence sediment trap. Repair/replace riprap and extend riprap down outlet channel to silt fence. • Adjust straw wattle placement below J-3 culvert outlet, to prevent bypass flow. Minor slumping evident on cut and fill approximately 40 yards south of J-3. The feature will need to be monitored and a decision made regarding the need for remedial grading prior to fall. • Another slump feature was noted on road fill, approximately 40 feet south of the outlet channel of Culvert J-7. The slump is approximately 40 feet wide, with a scarp of up to approximately 24". The feature will need to be monitored and a decision made regarding the need for remedial grading prior to fall. Temporary Channel/Gully Repair Access Routes • A temporary repair route used last fall extends from a point along the Ridgeline Access Road south of the upper end of 006-NE3 permanent drainage and extends downslope(west)to the vicinity of the powerline, north of Channel 006-E1. The route needs to be graded, roughened and seeded if it is no longer needed. If needed to provide access for further gully or channel repair work, rills that have developed in several steep segments need to be graded out and closely spaced water bars need to be installed along the route to prevent further rill erosion. Hydrologic Balance Snowpack had recently melted off most reclaimed areas, though a few drifts remained on north facing slopes at higher elevations. Sediment Ponds 009 and 015 located in narrow tributary drainages to Sage Creek could not be accessed due to remaining drifts and muddy conditions along the access routes. All other sediment ponds were accessed. The ponds were all full and discharging when observed, and embankments appeared to be stable. The following observations were made regarding sediment ponds that could be accessed: • Pond 005 was observed on the morning of 4/27/10; discharging clear flow over the top of the riser. • Pond 006 was observed on the afternoon of 4/27/10; discharging clear flow over the top of the riser. • Pond 017 was observed on the afternoon of 4/28/10; discharging clear flow over the top of the riser. • Pond 016A was observed on the afternoon of 4/28/10; discharging clear flow over the top of the riser. Some woody debris inside the trash rack needs to be cleaned out. Both the inlet and outlet channels associated with Culvert K-1 at the south inlet to the pond have scoured and require maintenance and riprap installation. There has been renewed slumping on the pond in-slope, in the same approximate location where slumping occurred and was repaired several years previously. The circular slide feature is located south of the PM-2 inlet channel, between the road and the standing pool. The feature is approximately 150' across, with a scarp height of up to approximately 8 feet. The feature appears to be associated with the larger slope stability problems in the lower 016/016A watershed, which are pending remediation subject to submittal and approval of a repair plan incorporating the results of recently completed hydrologic and geotechnical investigations. Repair of 5