Laserfiche WebLink
<br />-Lower Soil Tem~e~ature <br /> <br />A noticeable decline in forest populRtlona of small <br />1ll4mmals oc.eurred . fQUo",1np, ",inte.rs of he.avy 8no..,fall. <br />This was most evident in the numbers of deer mice <br />(Peromyscus man1culatua) but it waS also found in <br />chipmunks (Eutamiae minimus) and 10 Hicrotus spp. <br />The basic reason for the .poPulation decline deriveR <br />ftom the de1.".d growth of @'RlIenti.;t,1 Ro\"in,. fnnrl", An'" <br />results primarily from a delay in breedlnR. 80 that <br />",fewer litters are produced. The delayed growth or <br />plants walll a function ot lower soil tem(1crntures (till! <br />the: lonRel" ana,", cover. No similar errcl:t \Jilt' (0111111 <br />on the toad (~~) ~ o't' pocket gopl\(~r (},l~o,~~~Y~,! <br />talpoides) populations. <br /> <br />-Oeepe~ Snowpack <br /> <br />As snow dePth increased, elk (Cervus candensjs) ~~ <br />co areas where snow wa! shallower than 40 em. They <br />avoided regions with more than 10 ~m ot penetra~ <br />snow depth. A IS percent increase in snowpack may <br />decrease available elk winter range by B percent. <br />Sp~lnK move~nt of elk ~as moye 8t~on~lv associated <br />with the.scart of new Rrowth in mountain meadows toan <br />directly with the receding, .nowline. f.!"ple hAbJtAt <br />wall available for elk C::"Vin~ below the "nowLine and <br />without reRard to snow deDth <br /> <br />~lcrobe8 <br /> <br />Plant litter in the tundra decreased in srells llf <br />deeper I!IInowPack. Thil!ll Dreaumably reflects rCPlllWl1 hy <br />the additional flux of water through the srltt..", rl'ttllllr <br />than an incr...e in decomposition rates. <br /> <br />Abiotic Factors <br /> <br />The effects of the 8no ack on Boil erosion resuited <br />ro~ t e greater area 0 bare Boll left b the decreasc <br />n vegetat ve co"er atoun snow an s. Those predicted <br />for the tundra area of the San Juan Mountains derive <br />from either the additional snow depth or the additional <br />llIeltwater produeed by c::loud seeding. <br /> <br />-Deep~r Sno~ack <br /> <br />Ii r:ha AreB of 10oR-IastinG! snowbtlllks l'lClIl1l1(L:!(.!.~.E..'!". <br />increase in snowfall. local chanKes III the r:IlN. \If . <br />soil erosion on the bare surface 8rt>UI1J them m.w in. <br />crease by II factor of 10. This effecr;: should !lilt - <br />ext~nd be,ond the immediate Vicinity o[ already ~lC- <br />latinr soow drifts and 80 should not be ~ortant re;. <br />alona Iv. <br /> <br />-Additional Heltwater <br /> <br />Theoretical considerations 8ugRest that an increased <br />streamflow generated by cloud seeding should he <br />as.oelated with an Increase in the total .1mounl or <br />d1sBolved material removed from the target sre.'l. /"Ids <br />1& suppot'ted by empirical obsecvatt.ons of ro("k \.l{l:\llwr- <br />hlg retes and stre8m \.later qunllry III th.' tlllld'-'I <br />environment. However. thls lJffect \oJ! 11 I,,, ;\ [I'hl :IIHI <br />should not be concentrated spatially. <br /> <br />-fltstoricst Climntolo&v <br /> <br />Telllperatllr~ fIuctnst ton8 ovet tht. Ll/oIt \ ,'II y...., r'l III <br />dicate a cooling trend from till."' ),1t(! IH(IO'~ ~<, :11""1' <br />1930 when a revers81 oc.curred: precfpirat Inn '1'l'1\{1~ <br />are inver9.;!ly [(dated t<1 tp.mrer;Hur~ '.r. lids, flll'I', <br />r:rendR arc qujt~ dfffer/'nt fr'lrn Il" ~"I' ,'~.I III <br />parts of tht! Northl:!rn Hp'lll!'>plt;;or... ;,., ""1:11 I" 'I' \, <br /> <br />tlfln flucllHltlonB Ahow rapid trllnsltinns from rlllacivp.- <br />Iy cfq' to rr.liltively wet mode:'!:. <br /> <br />-SlIver <br /> <br />No signIficant increase in silve~ c::onc.entrstion were <br />found in the target area, exce t in saall areas near <br />generator s tes. 8 tcr our winters 0 seedinR. No <br />deleterious effeces ol silver iodide additions have <br />been noted at concentrations. which could be expected <br />dU(l to cloud set'din&. <br /> <br />HISTORY ANn OF-RIGN <br /> <br />Thl~ Son Junn Ikol08Y. Project W.18 established ns one nf <br />11 complex of investigations ariaing from the need to <br />explore the possibilities of Inc~ea81ng the availabll- <br />itS of water in the UnIted States Southwest. In 1968 <br />Congress authorized the Bureau of Reclasatlon to <br />initiate weather modification pilot projects to test <br />the feasibiltty of large 8cale winter cloud seedtng <br />\oJhich showed promise, of being an economical technique <br />fnr augmenting the flow of the ColoradO River (DivisIon <br />o[ Atmospheric Water Resources Management 1910). <br />An~lYsis of previous research findinRs indicated that <br />llll.' mUAt likely chance of _u(teas .would come from <br />wiuter seeding of orofraPhic _torma.over sOPle of the <br />hi II mountn in IlrOR" s tuated In the Upper COlorndo <br />River Baa n. Grant et I!I. . teste t a approach <br />011 a limited acale at Climax. Colora o. an oun <br />slRnlficant increa.es in snowfall when leeding e_per- <br />I (mcnte were erfor~ed under specific,westher sitU8tion8. <br />Know e e accru n rom t 8 atu an rOd two at lers <br />i" Colorndo Steam oat r n I an ree .'8, <br />and from a Netland Aca emy 0 0 enoe. eport <br />led to the conclusion that c::aretu~~y managed w1nter <br />cloud-aeedin techn1 ues could roduce 8 lU to jU <br />perccnt incres.ae n mounta n sno..... a e ureau of <br />Rcr.ln~'tion designed the Colorado River Basin Pilot <br />ProJ~ct (port of Project Skyvster) to test this <br />POR91hil1ty on a sub-operational scale. The mast re- <br />cent Rtatement on the effectiveness of this deaign Is <br />9,lvpn in fIlUll/Mry form by Howell (thh Chapter). <br /> <br />Tlll~ Sau .hUlIl Mountains of southwestern Colorado were <br />dlilBCII aR the si te of the cloud seeding pUot project <br />ht'('.'IlH(> flf th~'-r l'Itrntegic location fOT intercept{.na <br />I.-I lit 1'1 n"Il,\rnphll' HtormA ftertvlng frnm the RouthweAt <br />\""h I d. ....1I11ld JIll SII enBureo rellltively frequent (H:cutrence <br />I)f il doud-top tet:lper-nture condition calcular;:ed to be <br />within the mOflt effective seeding range of above ...26 C. <br />The ol'181n81 atea destined ~o t'e<:.ehe ~he. cloud-seed- <br />tng experiment V48 8.5.50 km (3.300 lIIi ) on the west- <br />ern side of the Continental Divide. and above 2.900 na <br />(9,500 ft) elevation (Fig. 1).. <br /> <br /> <br />~.. <br /> <br />A~"ltl Ilru <br />1-,I.....'.h.. <br />I-.""'''''I.h <br />ro.cUIIIU <br />.................. <br />.-..lOe.... <br />..."'. <br /> <br />t" <br /> <br />. :1'.'11"" I. <':"11 luan \'loud Ii<'e-dfnn tllJ'ltet. arelt. ltnrl <br />IU."03Lvl' Sflld,' 9itt>A. <br /> <br />20 <br /> <br />A-13-11 <br />