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<br />areas and unfinished upper perimeter ditch segments to impact lower portions of the refuse pile diversion
<br />and collection system, including the terrace drains. This increases the potential for sediment deposition and
<br />erosion on reclaimed benches. Deposition ofcoaly sediments or erosion of the reclaimed benches or lower
<br />ditch segments would necessitate mitigative work on the completed areas.
<br />In the specific case of CRDA-I, final grading of the upper two benchoutslopes and terrace drains has not
<br />been completed, terrace drain outslopes are over-steepened in some locations, the upper two benches have
<br />not been cover-soiled, and upper segments of the permanent perimeter ditches have not beenriprapped.
<br />Essentially the same situation exists at CRDA-2. In addition, on CRDA-2, a temporary haulage road angles
<br />across the face of the pile, and completion of final terrace drains on the reclaimed benches in accordance
<br />with approved fmal designs cannot be performed until the road has been reclaimed. Further, at CRDA-2,
<br />the Division has identified concerns with the suitability of the existing upper diversion as a permanent
<br />structure, and a new upper diversion is to be completed as a component of CRDA-2 final reclamation.
<br />Adequacy Item 9 requested "as built" contours and cross-sections for reclaimed areas at the South Fan, 2
<br />West Portals, and North Decline, including certifications for the permanent reclaimed channels at the North
<br />Decline and 2 West Portals. Documentation submitted by the applicant indicates that the reclamation in
<br />these areas was conducted in compliance with the approved plan. This assessment is supported by
<br />observations and measurements made during the bond release inspection on August 14, I5, and 24, 2001.
<br />At the North Decline, settling of the portal decline fill in the vicinity of the lower segment of the permanent
<br />channel has resulted in a lowering of the original contours, and creation of a shallow depression in the
<br />channel which pools water when the channel flows. Over time, the depression will fill in with sediment,
<br />but in the interim the settlement has resulted in the creation of a small wetland area, with no evident
<br />negative ramifications to channel stability. Permit Exhibit 21 specifies a steep channel segment (7.5%) and
<br />a low gradient channel segment (2.5%) with design parameters for each segment. The original channel
<br />construction was certified by Larry Reschke of PCC, in 1995, and a segment reconstructed in 2000 in
<br />association with Ute Water Line installation, was certified by Jim Stover in July, 2001. Representative
<br />channel bottom widths of 35' and 38' were measured during the bond release inspection, with
<br />representative depths of 34", 36" and 38" (including berm height), and 22" and 27" (not including berm
<br />height). Required bottom width is 35', with depth of 24". The low gradient channel segment of the Ute
<br />Water reconstruction reach was estimated using an abney level to be approximately 5%. Jim Stover's
<br />surveyed grade for the segment was 3.2%. Given the relative precision to be expected with anabney, the
<br />surveyed grade is considered reasonable. This compares to design gradient of 2.5%. In his certification,
<br />Mr. Stover included a table relating Flow depth to velocity, showing that the design ramifications of the
<br />discrepancy between the design specification and the surveyed gradient were insignificant. The high
<br />gradient segment of the channel, immediately downstream from the Ute Water reconstruction reach, was
<br />estimated with the abney level to be approximately 8%, which is comparable to the design specification of
<br />7.5%. The channel has functioned well since original construction in 1992, with no significant erosion and
<br />no instances of storm flow escaping the channel. The North Decline reclaimed areas on either side of the
<br />channel are stable, and relatively Flat, appear to be similar to [he original land form, and blend into the
<br />adjacent terrain.
<br />Two west portal reclaimed slopes blend smoothly into the adjacenthillslopes, with no highwall remnant.
<br />Proposed final reclamation cross-sections on Exhibit 58 indicate slightly concave slope configurations, with
<br />gradient of 33% for the North Portal and 46% for the South Portal. During the bond release inspection on
<br />August 24, the North Portal backfill gradient was estimated with anabney level to be approximately 34%,
<br />and [he South Portal backfill gradient was estimated to be approximately 38%. Both slopes are slightly
<br />concave, as depicted in the approved design. The slopes were graded rough, and no erosion was evident.
<br />Silt fence and berm sediment controls were in place in accordance with the approved design, and were
<br />properly maintained.
<br />The permanent channel at the Two West Portals appeared to be constructed in accordance with the
<br />approved design. M inor erosion repair and riprap installation was requested during the inspection on
<br />August 14, and adequate repair was documented during the inspection on August 24.
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