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These conditions should be the worst case conditions for saturation and <br /> pore water pressures in the fill and should address the potential for any <br /> increased pore water pressures associated with the local seeps and <br /> perched water. <br /> 13. Dry seismic conditions were evaluated and saturated conditions at the <br /> base of the slope (5 feet at base) were evaluated, but not seeps with <br /> seismic conditions or saturated conditions along the entire fill slope. <br /> o How are seeps and perched water areas identified in the quarry, <br /> or seasonally wet slopes represented? <br /> o Was flood and toe-scour evaluated? <br /> o What size flood event is likely to impact slope stability? <br /> Response: <br /> Generally, extreme hydrologic and extreme seismic conditions are not <br /> evaluated together as combined loading conditions due to the low <br /> probabilities of both these extreme events occurring at the same time. <br /> The seeps and perched water, and seasonally wet slopes are <br /> represented in the analysis of the extreme case of saturated conditions. <br /> The flood and toe scour are being evaluated as described in the <br /> response to Comment 1, under 6.4.5 Exhibit E— Reclamation Plan. The <br /> 100 year flood event is the design event for the flood and toe scour <br /> evaluations. <br /> 14. Existing fill is already present in the quarry. It is not clear whether this <br /> fill is documented/controlled fill to the specifications of the final <br /> reclamation plans, or uncontrolled fill. <br /> o What site preparation will occur prior to final fill placement? <br /> o Will existing fill be removed/recompacted? <br /> o The report specifies final fill placement be in maximum 2 foot lifts <br /> and compacted to greater than 90% maximum dry density. Does <br /> the existing fill meet the standards and recommendations outlined <br /> in report? <br /> Response: <br /> The existing fill was evaluated based on the properties of the in-place fill, <br /> assuming it was an uncontrolled fill. The reclamation plan allows the <br /> existing fill to remain in place, but the specifications will require clearing, <br /> grubbing, moisture conditioning, and compaction to 90 percent of <br /> maximum dry density for any surfaces to receive new fill. <br /> hdrinc.com <br /> 1670 Broadway, Suite 3400, Denver, CO 80202-4824 <br /> (303)764-1520 <br />