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<br />~~ <br />U <br />Fairly uniform downslope deformations are indicated over an <br />interval from 16 to 42 feet below the ground surface by <br />inclinometer I-4. This suggests a general creeping downslope of <br />the fill within this zone. The rate of downslope movement has <br />varied considerably over the twelve months of monitoring, <br />ranging from 0 to in excess of 0.6 inches per month. The <br />reasons for this variation are not apparent, but may be related <br />to runoff from melting of the heavy snowpack during the summer <br />months. Total downslope movements .exceed three inches. No <br />significant water pressures have been measured within the fill. <br />Additional material that was placed close to the crest of the <br />fill may have contributed to the fill deformation rate as well. <br />5.2 Impact of Reclamation <br />The Fan Level Fill (Zone I-D) will be reclaimed by <br />flattening the existing fill outslope to 2(H) 1(V). The <br />crest of the fill will be removed; the excavated material from <br />this fill portion will be used to backfill the diversion ditch <br />and to buttress the Diversion Ditch Cut. This will be followed <br />by appropriate surface drainage and revegetation. <br />Our stability analyses indicate that the safety factor of <br />the existing fill will be increased by the flattening of the <br />slope, and that an adequate safety factor for long-term <br />stability will result. Downslope deformations should be reduced <br />to an acceptable level or eliminated. <br />6.0 DIVERSION DITCH CUT (ZONE 3-B) <br />6.1 Monitoring Results <br />Inclinometer I-5, installed within the Diversion Ditch <br />Cut, shows virtually no deformations, indicating that this cut <br />is currently stable. No water pressures have been measured at <br />this location. The cut portion where the inclinometer has been <br />installed is in colluvial soils; other parts of this cut have <br />been excavated in bedrock. <br />Sloughing of the cut face west of the inclinometer I-5 has <br />been recently observed. The reasons for this sloughing are not <br />obvious. We recommend that this cut portion be closely <br />inspected for a period of one year; modifications fn the <br />reclaimed cut configuration should be made if sloughing <br />continues or its size and/or rate increases. <br />r,EO*ro000Or+w~nNC, n+e. <br />. 1 .`y, . <br />