WMOD00281

• Title: The Impacts of Snow Enhancement - Technology Assessment of Winter Orographic Snowpack Augmentation in the Upper Colorado River Basin
• Date: 1/1/1974
• State: CO
• Weather Modification - Doc Type: Report

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b. Ecological Impacts

The ecological impact of the \VaSA program will...n:s.u.l.Li1L.f.c..%Jf an~>
sudden or cat.astropmcccologicaJ cha!)g~ In view of the fact that plant and
animal communJti~s change slowly in response to environmental alteration,
tbe change wHI be reflected in cumulative year-te-year changes in abundance
of species and slight shifts in rates of reproduction, growth, .anCl production.
In other cases where a species is unable to survive or migrate, it llIay becom<:
less numerous or even extinct.
The.2.!!s:reased snowpack-~c direct e~ts on aquatic life, wildlife
and habitat, and insects. Because of the IDlaerobic conditions resulLil1~ from
sn(~ver: mQre whiter fish kills~ be I?roduccd in 1110un1..1jn I~s. 1n-
crea~ed snowpack will lead to a re~at downward of the upper limit of the.
for~ary. A longer snow season in the. forest will force deer, elkd~
livestock tt, remain lon~cr on winter ranges at lower clcvati9n~. An IDCJ:Case
hi ,~ length of time "perit on winter ran~es can reduce thee-Jlumber,s .hat
~vive from year to-'y~ar. The change,., in vegetation resulting from increased
snowpack will mean that herbivorous species of mamm~Is, birds, and insects
wiH also change. In turn., the carnivores orall c1ass.es will be affected and cvcn-
tuaJly the scavengers and decomposers,. including the soil microbes, wiIJ rc.
spond. Even trends in soil retention and formation will be altered as a result
of the kind of vegetation-growing on it. The increased snow cover n.Qt only n~
h!:!.p ensure oPJ~m cnn~ions for biQQf"n<tlion of insect~ bllt also mar-~ri--'-
l1uenc.e..jhe entire courSe of active development of terrc.<;tl'ial insects in the
summer.
The silver iodide used in WOSA will result in relatively heavy deposits
near the generator sites; SOUlC will be assoCiated with the precipit<ltion and the
remainder wilJ be widely dispersed. On the basis of limited knowledge, i~Ei-
no~resccn thatsnve~Jlid.c..;,yj!1 create problems of toxicity for~rreStrial,
or aqua~Ifadvcrse effectS should materialize, they are_
~~Y- tn h,~ .Q.o...ll1Vertebratcs or soil microbej.
Analysis of limited data on health (lnd mortality does not indicate a rela-
tionship between the amount of snowfall and human health impairment
Indirect eflVironmcntal effects of a WOSA program could affect tbe
success of dependent communities of organisms. Augmentation of th4.:~snow-
pack would generally result in Jowcr mean ~vater tt:TQper.aUJre.<: rhuing..Jhe..
s~ Differences of on)rrtewcregrees may alter tbe distribution of
aquatic organisms and interfere with breeding se<.lsons, life cycles, growth, and
development.
The inc~4Jnelt~wateLnUlQ!I from a WOSAprogram would increase
sustained .flow on a seasonal.basis and would magnify flood peaks. Variou$.
environmentaJ effects in streams could result includiligw~~g away.oLat-
t~h~gac. rcduc~~~.~te.1alli).3.,remQyalof '~UlnuJ~~tlls
that forms thchaqitat an~ food of many species of stream invertebrates, de-
struction and w~ away Q{ fish eegli, intcrfert!'}cc ~iLh..spawning,and an
j1!~ldcd segwt:nt. Major or extreme changes resulting from

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