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<br />VANICi':K ANII KHA1\\i':H-SVUAWFISlI ANIl CHUB Ln'E IIIS'l'OHY
<br />
<br />1%
<br />
<br />:r ABLE L-lI1can monthly and annual Green River n'isrhar{{e (euhic ft'el I)('r S,.co,lt/) Iwf"rc IIn,z after
<br />i"'I'OI/I/t1I1/"lIl, (;"'t'l/dlll,~ (colI/pilcd from U, S, (;"oll"i,,"1 .)lIrl"'Y d"r,,)
<br />(
<br />,
<br />
<br /> Belore impoundment After impoundment
<br /> (1951-1962)
<br />Month Mean Range ]963 ]964 ]965 1966
<br />October 920 573- ],608 777 ]28 2,583 ],279
<br />Nnvemhl"r 8]4 576- 1 ,338 flOO 312 2,343 2,024
<br />))ccenJbcr 628 323- 988 26S 743 3,IS1 ],881
<br />January 597 391- 814 367 tl~9 3,S06 1,164
<br />J."'ebrllary 792 442- 1,503 467 966 3,838 ],293
<br />.. Marl.h ],4]3 709- 2,434 ]06 500 3,7B2 ],]52
<br />'.. April 2,752 1,274- 6,288 13.1 5117 3,4:20 2,171
<br />May 4,462 1,278- 6,614 ]30 1,477 I,071l 1,3S2
<br />June 6,996 3,227-11,420 ]2S 1,466 1,43'1 1,5'10
<br />July 3,375 909- 6,995 104 2,441 474 1,692
<br />August 1,635 700- 3,711 102 ],992 4H7 ],921
<br />S..ptcmhcr 913 643- 1,640 113 2,200 73.1 2,078
<br />
<br />Annual meant
<br />
<br />] ,032- 3,226
<br />
<br />--.-------------------------------------------------------------------------------------
<br />
<br />2,102
<br />
<br />23]
<br />
<br />1,.555
<br />
<br />2.227
<br />
<br />],63.3
<br />
<br />1 Calculated for "water-years'~ which hegin on October 1 of the preceding (:alenuar-year.
<br />
<br />the two morphological varian:s. Consequently,
<br />specimens shorter than 200 mm total length
<br />were combined in the present study under the
<br />1!:cneral taxon, Colorado chub. All other names
<br />of fi~"es were tuken from those listed by the
<br />American Fisheries Society ll960) ,
<br />
<br />1'1lY~ICAL Al'\D CIIEM ]eAL CIIAHACTEHISTlCS
<br />
<br />Before completion of Flaming Gorge Dam,
<br />Crecn Hil'cr flow entering Dinosaur Nalional
<br />l\lonumcnt was lowest during winter monlb
<br />and increased gradually until peak run-off in
<br />June (Table 1). Following peak run-off, flow
<br />receded during the summer and was ulli-
<br />formly low during fall months. Since com-
<br />pil'I ion of Flaming Gorge Dam, thc annllal
<br />discharge pattern of the Green River has been
<br />greatly altered. The characteristic high spring
<br />and low winter flows have been replaced by
<br />
<br />a relatively stabilized seasonal discharge pat-
<br />tern. Below the mouth of the Yampa River,
<br />the Green River has been altered less because
<br />the Yampa waters modify the dam's impact,
<br />and the seasonal flow pallern resembles thai
<br />of preimpoundment years.
<br />Before impoundment, yearly water tempera-
<br />lurc pallcrns werc similar at Greendale and
<br />Jensen; tempcratures began rising from win-
<br />ter lows of 3:) F in March and reached a
<br />mcan of ahoul 72 F in July (Tablc 2). In
<br />late August temperatures began a steady
<br />decline to winter lows in December. Since
<br />dam closure, water tcmperatures at Green-
<br />dale showed lillle seasonal fluctuation and
<br />n~mailled lar;.:cly in the 3S--S0 F range, Be-
<br />low the mouth of the Yampn River, post.
<br />impoundmcnt seasonal tempcrature resembled
<br />the pre-impoundment pattern, although post-
<br />impoundment temperatures were slightly lower
<br />
<br />TABLE 2,-Meun monthly Green River water temperatures (OF), before and after impol/ndmcnt, Greelldale
<br />and Jensen, Utah (compiled from USGS data)
<br />
<br /> Greendale Jensen
<br /> Before After Beiore AflPr
<br /> impoundment impoundment impollndnlPnt ilnpOl~lldment
<br /> ------------
<br />AllIlllh 1 U57-S0 ]!l63 ]!llll ]9G,~ ]0(;(, 1!l57-S!1: lD(j;; I!J(j:J ]!l(jl ]!l65 I!){j()
<br />------.---
<br />January 33 36 41 4] 4.5 :J3 32 3;; 32
<br />F('hnlnry 33 35 37 3R 41 :J.1 3.3 32 3H
<br />AIMCh 36 36 .18 39 3!l 3H 4.1 3') 3D
<br />April 45 36 40 40 3!J 4H 'I!J 48 45 40
<br />M'1\" 52 39 41 42 3!l SH 5!J .')(l ,~4 51l
<br />J Ullc 60 4] 42 46 40 6.1 66 61 no 62
<br />JlIly 70 43 4S 49 41 72 -., 66 67 61l
<br /> ,-
<br />August 6R 44 47 so .j3 70 7~ 6.1 (;r; 64
<br />September 60 42 48 S] '1-1 64 (i6 5!l 57 5B
<br />Ol'lobcr 50 43 54 5.1 SO 53 54
<br />Novemher 35 58 53 53 31> .I:! 47
<br />Dcc.--ember 33 .J8 46 40 3.J 1" 37
<br />
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