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<br />10
<br />
<br />
<br />00133 'l
<br />
<br />map.,prepar-ed o.y theUnit-edSta-tesW eath-eI'Bureau sh,ow that the
<br />
<br />averageannualevapol'atienfrom-a-lakesu,rfaeei-n the Pacific
<br />
<br />Seuthwestarea varljes,fl'o.ma minimum of about 30 inches in
<br />
<br />the no,rthern mountainous al'ea to a maximum of 86-inc,hes in
<br />
<br />lower pal'ts oft"1\e Gi1aan~ Colorado River,'basins~U .5. W. B.,
<br />
<br />
<br />19&<t}. Fl'om1.0 teaO pel'centof th1-S l~s eccur,.inth-e (, summer
<br />
<br />month.s, May to October ,- When,~st1'a..gesare'inu,.e . Total'
<br />
<br />.
<br />
<br />s~oek waterr'equil'e~en~sfG:i!'IOOhe~l!l-efcatt'ledu-l'ing this
<br />,period-will, be il.bout '1-84,O-O,Og~Hons.ol'.O.57'ael'-e-ft.This is
<br />e<1!uivaleilt-b0th-e'e\<aperaUonf~om"O,a4acre o"f~n water in
<br />
<br />,
<br />the,n.orth where evapor-a-tionis,at-<l,,!,init!num ,or to 0.1 aC;re in
<br />
<br />thesQ\l\Jhwhereevaporationis -at a maxim~rp. Ther-equfrements
<br />
<br />quet-~arefor:StQe,k, use-',only.anddonot ind\l~kanythin-g' for lOeSS
<br />
<br />"'''l'"vi-asteresul-ti.ng ,fl'-Gffll;t-orag,eint-a,nks,ortroughs.
<br />, ' ,
<br />
<br />.
<br />
<br />The-am-aant,-'of :tl'-aluipil'a-ti~Rl-oll.S ~y-ve-ge-tation-v.a de s in
<br />
<br />,-a~<l__d-anee '-*Hh.a num-b<;r-offEl-ctors,inelooing-plaBts,pecies,
<br />'~sity-atad h-e,i:ght, -'of;'eg-'etat!en, ,dePth~ thew-at-ert&b.le ,temper-
<br />, , , ,
<br />
<br />," j ", \" ,"- . . ,,-.., '. r
<br />ature,a.nd.theilu-~b,r-o!t'4aylight hou:i!'s-,'rhe.~u.bj_t'has been
<br />, . , .
<br />
<br />,4i..wS'll-ed..hyf .-s-e_'l'-alil'l_.tiga-to'l'&-atHl'-vu~'methods fo I'
<br />
<br />me-&sui'-ing- or estimat.ing' the:us.e:~fwa.t-erby diff~rent tyPes of'
<br />pl-attt.~n'heen' dev-eloped.. Gne,ofthe.,<;!-Gmmonly~d,J::nel:hods
<br />isHtheempi:l'ic-al.alaney~r-i-Qdle formula, (IiH",ney , -W.F 0' ~nd
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