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<br />/---'1 <br /> <br />.. <br /> <br />6, <br /> <br />JIl' <br />:ii' <br /> <br />003329 <br /> <br />In mid-June, Mr, David Stark, the USFS District Ranger, Minturn, <br />asked for specific recommendations for changes in drainage <br />management that would decrease the risk of serious 1ands1iding on <br />Meadow Mountain, At that time we were still installing the <br />monitoring system and carrying out field studies of the landslides <br />and had not had time to evaluate the overall situation, <br />Consequently, at that time, we were very conservative in <br />recommending radical changes in water management, However, with <br />still incomplete data, but a great deal more than when the project <br />started. it seems prudent to take measures designed to reduce <br />percolation of surface water into the slide to a minimum, This <br />might include: A. Elimination or reduction of standing water in <br />ponds and bogs; B, Increasing the efficiency of drainage and <br />reducing the residence time of surface water in natural drainages <br />and during the snowmelt season, in irrigation ditches; C, Actively <br />draining the lower parts of the "highway" landslide and possibly the <br />"intermediate landslide; D, In time. changing the overall <br />irrigation scheme on Meadow Mountain to reduce water percolation <br />during the summer months, <br /> <br />Toward the end of the drilling program on Meadow Mountain, drill <br />holes 8 and 9 were completed in Belden Shale at 154 and 160 feet <br />respectively,' At this time and as reported to me on September 10, <br />1985. by Marion Welles, CDOH, an inclination measurement sonde has <br />been run into each of these holes three times with no signjficant <br />changes so far, Additionally hole 8 experienced an apparent <br />mechanical problem with the casing flutes which makes it impossible <br />to determine a vector of landslide motion, If this mechanical <br />difficulty is overcome, the real value of inclinometers should <br />become apparent next season. It should also be noted that CDOH <br />installed an inclinometer at the base of the "highway" landslide to <br />depth of about 75 ft below surface but the rapid movement, of this <br />landslide destroyed the installation early in the investigation. <br /> <br />7, One difficulty encountered near the end of the drilling program on <br />Meadow Mountain was that it became apparent that in order to <br />determine an approximate volume of material that might move in the <br />"i ntermedi ate" 1 ands1 i de a drill ho1 e wou1 d be needed approximately <br />500 ft downslope from drill hole 8, This proposed hole was not <br />dri 11 ~d because, another ,1 ocati on (drill ho1 e 9) w,as drilled i hstead <br />and' an, i nclinometeri nstalled'iffi t;'- 'By the't.ime: of' ~ompleti on of ' <br />this additional hole. time and bydget constraints forced us to move <br />the drilling equipment to the Whiskey Creek landslide drill s;te~ <br />It is recommended that this hole be drilled as early as possible in <br />1986, <br /> <br />- 7 - <br />