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<br />. tp:<:;l_ '-Q2 11"1> <br />'" . ..1 ,JC, <br /> <br />6: 10 <br /> <br />TUb <br /> <br />I :3(1 <br /> <br />that cottonwood nu!nt.":r1.:':!nce flows are about three t.o four tines greater t.han <br />the average. 3nnual di\lerted flows, and about f.;)rty to sixty percent of the <br />estInated annl!al n",tlOcal flf)~t. 1 <br /> <br />Toe seasona.lity of growth can change as a r-esult of dlver.:lion flo...". for <br />exa~ple, the Rush Creek d!ver.sion creat.es an artificial hydrog:oaph peak in <br />July, as opposed to the prediverslon peak 1n June (the di\lersion peak Is twenty <br />percent of the prediverslon peak). As a consequence tee main growth period for <br />black cottonwood shifted from May -- predi~erslon, to July/August -. diversion <br />(strcrnoorg and Patt"!n ~990). The arn:.Jal dia/!letel' increment also decreases as a <br />resulL of the poorer growth conditions (temperature, relative hUGlidlty, soil <br />moist.ure to name a few) that occur during the later "groioling season." <br /> <br />Stro~bt!rg and PattEn (1991) determi:lcd that the presence of cottonwood cannot <br />be int.erpreted as an indicator of sufficient flows. The flous necessary to <br />ensure cottonOlood recrult.nent ar'e different t.han those which ::laintain existtog <br />cott.onwood stands -- bot.h i.n quantity 3;ld in timing. In ger-eral, maintenance <br />fiO\;s are less tMn recruitment floHs, so e'Jen if tr:e current cottcnwood stands <br />~ersis~ rege~e:oation "ill not occur 1~ naintenar.ce is the only objective. They <br />also cun:::lurl6d t!1J.t grcwlh and (hI.' :-elationships can aid in deterl'linlng <br />rIparian Dased streamflow requirer.1ents, presuming that plant individual and <br />co~munlty maintenance is depe~dent on certain l~vels of growth rates (Stro~berg <br />ar~1 Fa t ter. 1,90). <br /> <br />Sueden <br /> <br />t-4.ost riparian hf..bitat in $wo:::lell has besn affected by streamflow regulation. <br />The effe~t has b<:er. c.he ccr:plet.e destl"ucti~1l of ripadan habttat I alt.notlgh some <br />in':!i v idu:;"'41 SpeCifo-5 I':ave adapte'~ to ne..' €n':iron!:l!::nts. Bllt even !:lore <br />Sig.~11fi.c:ant, peak rur:-off .!.p 'J:'.rE::g.l'l~ti?d S~l"ea::lS of r.on.hero Swecen occurs <br /> <br />~'-Irin6 snolme~t, iT} ':ol1e ~P~i!16ti.,€:. <br /> <br />The s~J.sor.::;.l floodir':g naintalns t.he <br /> <br />---------- .----- .. <br /> <br />17:..;; c",,",,,:,u !~ C\....~! ~.I1...d ~-;. "'E~(f,,-.;:~ ~~;,;' tr.;os<2 s:t.e-.:Spe:iftC c0;I~lusion$ <br />.;,:'e L.-iI:$':' _,~ ~. ,- . 1'.,~'\i~'_',,~o:: ~r,~y a.n~ -!:: n::.t :-ef1e-ct :::J.inte:18.:1ce <br />rc:.pi:"';:::':::!:i::;: f ~ (;r.-:-'c: ~~..."-,~ !J;::';'.'''::,s. SI..:-:.;I". ~s ....ill.-:-!..". ~l~e:-. qapie, forbs, <br />~T'.~:!.s.;::;,".::~'::f::il ;;;;,,,", r,1.,;'~.-,;3, <br />