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<br />Appendix to Question No-:- 4 <br /> <br />~ <br /> <br />. <br /> <br />. <br /> <br />P'rc..- <br /> <br />11'1:: P,...f14'::o:: <br />Co ...,,...1,...1 b, <br /> <br />t.;f "Ti,< r_r....h l:t 5......... E....t..........c:..........~T.. <br />L..eLo. t..,;. l.._.)~;Jb<!.:..K<::... - 197Y <br /> <br />The co~~uta~lons of increases due to secdinc ~crc cx~mincd <br />to see it the au~cnted a~unt tended to be relatively large when the <br />natural snowfall ~as targe, or conversely. This set of d~t3 is shown in <br />Fl~re 14(8). Although limited in size, the sample indicates that there <br />ls a positive relationship, The natural snowfall and a~unts produced by <br />s~edlng have a linear correlation of 0.6, The increases were also computed <br />as a percentage of the natural snowfall. figure 14(b) sho~s that this per- <br />centaGe is not dependent on natut.:Jl sn(ll"'[all. Thereforc. the same pcrccnt- <br />.~e snow liiIuf:fllentatlon lIlay be used In both. 10'" and h.i!:h. years of natur:!l <br />snowla 11. <br /> <br />\Ye may SUlIIlII8rize t.he discussion of sno...fall augmentation <br /> <br />as follo"'s: <br /> <br />(1) The most probable increase in snowfall ~t elevations <br />above 8000 ft that c~n be realized by seeding is in <br />the range from Dpproxi~Dtely 20 to 25 percent, as , <br />an average figure for the basin over a period of at <br />least several years. In our judpent the chance <br />that subsequent, long-term data will show that this <br />figure 1s less than 10 percent or greater than 35 <br />percent is less than one in ten. This assumes that <br />state of the art cloud seed1nr 1s done in :Ln optimal <br />lunner, If it is not done optimally then the percent <br />increa6e in snowfall will be less, <br /> <br />(2) The increases are produced mainiy by changing hours <br />in which little snowfall ~~uld have occurred <br />naturally Lnto hours of signific:lnt snowfall, As <br />a result, the days with relatively larbe amounts of <br />snow (e"., aMOunts greater than one half inch of <br />water equivalent) rill be olle and a half t.o t....ice as <br />frequent (see Figure 11). <br /> <br />(3) ,The proportional inCrease in snowfall produced by <br />seedin!: will be the same whether the season is ~et <br />or dry. <br /> <br />(4) The kernel of the effect of seeding is that it ...ill <br />make the sno...fall amount.s of the target area simil:!t <br />to the nat'irat snowfall that exis"t.s at elevations <br />500 to 1000 ft higher in the IIIQuntains, <br /> <br />As a simple but reasonably accurate rule for computing <br />~~_gmentcd seasonal snowfall, one may apply percentage increases to the <br />seasonal snowfall :LVerages. However, the percentage increases that <br />sho;id be applied t.o the different localitIes are not well known at this <br />t.IJ:lc, In the Light of dlscussions ....lth Professor Grant and our cOl:lputa- <br />tlons given earlier, we selected the percentage increases shown in <br />figure 15 as th~ ~~St probable est1mates. These percentage increases <br />were then applied to the seasonal snowfall of figure 7 to obtain the <br />:!verage snowfall (water equiv:Llent) that would be produced by seeding <br />methods that C~ltl be implemented within the next five years (Figure 16), <br />This m~p, and the t*O t~~t fallow, ....ere used extensively in the study to <br />cstlm:Jtc hydrolobic cOlHlitions and the effects on ...cologieal, social, :Ind <br />t'COIlOmJC systems; thert'foTc, they ;'lr<:> c;,:trcmcly important, <br /> <br />A-l1-1 <br />