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<br />Appendix to Question No.6 <br /> <br />Pi'''''" <br /> <br />1f,~ P"..fAcc: <br />C-"'_I".t..J ", <br /> <br />(;f 9Tf,< .r....r'~./." t:( .sl''''~ E'....t..."~c.~.......T.. <br />L.~~. L...J. Wr.;Jb<t..:..k.(,:...- 197"1 <br /> <br />The (:ompUtntll:ms of lncrcRSos (Jue to sccdlnj: '"ere eX:llninc(1 <br />to see It the _ugmcnted all'Ount tended to be ('elo.tlvely large when the <br />natural snowfall was large, or conversely. This set of data Is shown in <br />figure 14(8). ALthough ll~lted In size, the sample indicates that there <br />is . positive relationship, The natural snowfall and a~unts produced by <br />a~edlnc have a lInear correlation of 0.6. The increases were also computed <br />liS . percentaglt of the naturaL snowfall. Flj;ure 14 (b) shows that thls per- <br />centaGe Is not dependent on naturaL snowfall. Therefore. the same percent- <br />lfe ~now .u~ent.tlon DAY be used In both low and high years of natural <br />.no.fa 11 . <br /> <br />We ..y sUMmarize the discussion of snowfall augmentation <br /> <br />.. fc,llowa: <br /> <br />(1) Tho IIlOlt probable incroase in snowfall at elevations <br />abovo 8000 ft that can be realized by so~ding Is In <br />the ranee frQ. approxi~tely 20 to 25 percent, as <br />an aver. I. figure for the b.,ln ove~ a period of at <br />L.alt leveral years. In our judpent the chance -- <br />that lubsequent, lon~ten. data _ill show that thls <br />flgtlre La leas than 10 percent or Ire_tor tha,;- 35 <br />percent 1. 1... than one in ten. This assumes that <br />.t.te of the art cloud ~uledlnl Is dQne In an optimal <br />..rmer. It J.t is not done optimally then the percent <br />Inc~.D.. In anowf.ll will be less. <br /> <br />(2) The Incr..... are produced mainly by changing hours <br />In which little Ino.fall would have occu~rcd <br />naturally Into hour. of slgniflcant snowtall. As <br />a result, the daya with rolatively large amounts of <br />snow (O.I.. alltOUntl Ireator than on~ half inch or <br />water equivalent) will be aile and a half to t~ice as <br />frequent (see Figure 11). <br /> <br />(3) The proportional increase in snowt:J.ll prnduced by <br />seedin~ will be the s~me whether the season 1s wet <br />or dry. <br /> <br />(4) The ~ernel of the effect of seeding is that it will <br />make the snowtall amounts of the target Ilres similar <br />to the natural snowfall that exists at elevations <br />500 to 1000 ft higher in the mountains. <br /> <br />As . simple but roasonably accur.te rule for computing <br />augmented seasonnl sno.tall, one ~3Y apply percentage increases to the <br />seasonlll sna_IaU aVer"ll!;Qs. Iio....ever. the porcontage increases that <br />.h~';ld be appltod to the dilterent localitios are not well known at this <br />tL~u:. In the li.ght of dlscusILons wlth Professor Grsnt lInd our COlllpUtll- <br />tlons ~ivcn earlier, we scle~ted the percentnge tncreases shown In <br />fL~re IS il5 the most probable C9"tfmlltes. Thesa pl!rccntegc increases <br />were then applled to the seasonal snowfall of Figure 1 to obtain the <br />averollga snowtoll (water <:-qulvolent) that would be producli!d by seeding <br />Iftcthuds that CDn be implf.:mented within the next ltve yea"'9 (Figure) i6}. <br />This lImp, :Jlld the tlt'O rh4t follow, were used extcnsLvc!y in the study to <br />cstlmatc: hydrologi.c comlltlons and the eflects on ecological, sochl. and <br />t'COIlOIIHC s)'stcm.s; therefore. thc)' .1rc c.'Ctremcly impor-tant. <br /> <br />A-I I-I <br />