INSPEC22060 - Laserfiche WebLink

Home Browse Search

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. design specification. This same ditch extends to the north and ultimately into Pond RP-1. The lower, higher gradient section of the ditch has down-cut 6" to 12" along one short steep segment. Along this lower segment, the ditch at the base of the refuse slope is pazalleled by an outer ditch, which wasriprapped. The outer riprap ditch is a stable, "V" shaped channel, approximately 2' deep by 1 S wide. It would appear that the outer ditch is the actual permanent ditch specified in the permit. However, as currently configured, very little drainage is routed to the pond via the riprapped ditch, because any runoff from the vegetated refuse pile is contained within the inner ditch. Operator was advised to divert inner ditch into theriprapped outer ditch, at some point upgradient from the steep segment. East ditch appeared to meet specs along entire length, including upper low gradientvegetated segment and lower high gradient riprapped segment. Combined Refuse Area RP-2/3/4 All perimeter ditches are "temporary in-pit ditches". Final designs are not required to be in place until refuse slopes are covered and seeded, however the interim ditches aze to be maintained to provide design flow capacity and to be stable. Operator has indicated that ditch erosion identified as a concern in the March inspection report in the vicinity of West inlet to Pond RP-4 will be repaired when conditions allow prudent equipment access. The operator has also indicated that measures will be taken to stabilize the series of gullies averaging approximately 2 feet deep, along the boundary between the toe of the refuse and the inslope of Sediment Pond RP-4. The following additional observations were made during this inspection. • Downcutting has occurred along the lower segment of the East Perimeter ditch, above the upper-most rock check, within a section of channel previously lined with river cobble. Stabilization is warranted. • On the West Perimeter Ditch, maintenance is needed along a short segment of low gradient ditch approximately 300 feet west of the Pond4 west inlet, where coaly sediment has accumulated. • The lower end of the steep riprapped segment of the West Perimeter Ditch has down-cut 1 to 2 fee[ deep, and angular riprap needs to be installed within this segmeut, to extend theriprap section to the ditch comer, where gradient is significantly reduced. • A section of West Ditch just below the dozer crossing road (designated Segment 3 in Illus. 44) needs maintenance for sediment cleanout. Measured cross section was 15" d, with 8'tw. Design specif cation is 24" d, with 8' tw. Operator pointed out that if flow escaped the ditch in this location, it would re-enter the ditch a short distance below, which did appear to be the case. Regardless, ditch needs to be maintained to provide design capacity. • Straw bale check dams installed at various locations along the interim in-pit ditches have proven for the most part to be ineffective, and have resulted in channel side-cutting at several locations. Straw checks where channel sidecutting has occurred should be dismantled, and use of straw bale checks within the perimeter ditches should be discontinued.