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<br />geomorphic processes. Comparatively little sediment move- <br />ment is produced by the action of snow glide and creep over <br />the ground surface, by avalanches or by overland flow from <br />snowmelt. Stream channel processes are more obviously <br />responsive to the seasonal snowpack, since most alpine <br />streamflow derives from snowmelt, but are relatively <br />unimportant in the alpine area of the San Juan Mountains. <br />By exten~ion, this conclusion implies that the 30 percent <br />increase which might be produced by operational cloud <br />seeding should have little immediate, direct effect on <br />alpine erosion rates. II [12, p. 145, emphasis added] (In <br />this study, the 30 percent increase considered by Caine <br />exceeds the normally accepted IIconsensus increasell of 10 to <br />15 percent.) <br /> <br />Concerns have been expressed about the delay in snowpack meltout in the <br />spring as a result of increased precipitation. Climatic and meteorolog- <br />ical investigations in both the maritime-influenced Sierra Nevada and <br />the continental Rocky Mountains disclosed that temporary delays in <br />snowpack meltout could occur as a result of 10 to 15 percent increases <br />in snowfall. However, it is believed that snowmelt extension would <br />occur in protected areas, those that serve as snow traps, and those in <br />which permanent snowbanks or glaciers exist. One of the San Juan <br />Ecology Project studies included development of a snow cover recession <br />model for two study basins. The model illustrated that only a small <br />area actually experienced an extended period of snow cover. In discuss- <br />ing the effect of a 15 percent increase in snowfall in the two San Juan <br /> <br />21 <br />