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<br />FAX NO. 970 490 2621 <br /> <br />p, 06/14 <br /> <br />NOV-t3-96 WED 10: 10 AI1 DOW FT COLLINS <br /> <br />. <br /> <br />. <br /> <br />. <br /> <br />NORTH FORK POUDRE RIVER <br />PHANTOM CANYON FISH KILL INVESTIGATIONS <br />OCfOBERl996 <br /> <br />The entire Sln:ll:hofthc Nonb FOlk oflhe POQCbWllS waIkod hm 1bc clam at fianigan Rcacrvoir to <br />approximately U4 mile ~ of1bc irzi&atioa aqueduct 0WIIlld by North Poadre IrrigatioD Company <br />(NFl). Our intent \Vas to detmnine dill cxteDt of the fi$h kill md assess lhe siltatian problem in the 8lreBm <br />d,,,rmeI Overall the.Ioss ofbabitat IIld fish in this 6 mile seetion of the North FOlk ofthc Poudre was <br />significant. <br /> <br />FISH KILL <br /> <br />On Odobcz' 3, 1996 the upper strelCb ofriver (down to the Nature CQnservllllC)". visitor c:catec) _ waIkcd <br />to COUIIt dead fish and.look far cvidcncc of Jive.fish. Dead fish ~ wen: disc"",imICCJ quiddy due to the <br />m""Mr, of fish \WUc:h bad been buried by the silt. HO\VeVl:I' fourspccies of dead fish wen: sec:n; White <br />sucker, longnosc SIlCkcr. brown trout aDd rainbow UOUl The v.bites sudrcrs may have been fish v.bic:b bad <br />left the mc:rvoir during the ~ process, while !he other species wen: wild resident populatiOll$ of the <br />NOrth Fork of the Poudrc River. live fish seen in this section included large numbers otfathcad minnows, <br />Iongnosc dace aDd low numbers ofkmgJ'''S'' sud:cn. Live fish appeared in the lower baIf'lni1c of this SlrWn <br />reach. On <Xtobcr 4. 1996 a samplini station was eo'1ducted at the North Poudrc Irrigation Company's <br />aqueduct (5.9 mile$ dowasttcam of Halligan) wbic:b produced adequate populations of both brown 1IOUt (61 <br />IbslA) aDdlongnose SllCkCl'S (31lbs1M. <br /> <br />On Oaobcr' 5, 1996 the Iowa' section (fiam the Natln CoDscrvlll1'Yvisitcrca1ler to the NPI aqueduct) was <br />clcctrofished to dctaminc the cxteDt oflhc kill on both J""8"'^"" sudrcrs aDd tmIt Viable sucla:t population <br />wcrofound 2.0 miles cIowDStreamofHalligan Reservoir. Viable trout popul...""" wcreDQt found 1IIl1i13.2 <br />miles below the reservoir. Below 3.2 miles fish populations were similar to those fOllDd at the aqueduct. <br /> <br />Based 011 a kill zone of3.2 miles and urili7i'l8 the 1983 data (Fausc:b 1984) md 1984 data (CDOW) an <br />estimated 4250 trout wen: killed cIurini this event. The Fausc:b (1984) data duIraclcrized the upper narrow <br />C8ny0ll section of the river and estimated 1529 troUt per mile. The 1984 Division of Wildlife data <br />characU:rizcs the more open meadow ec:ctioo near liI.c prcscrvc visitors I:CIltcr with an -'mo'", of 741 fish per <br />mile. Based on river gcomorphomctly the Fausc:b data was u'Hhcd to predi<:t 2.4 miles of the kill zone llIId <br />tIic CDOW used to predict the lower 0.8 miles of !he lcill2OIlC. <br /> <br />SILTATION <br /> <br />Transects wen: plac:cd in lhe first 1200 feet (every 100 ft.)of stream below tbc outlet ofHaUigan Reservoir to <br />by to cstiJ:oatc tbc tota1 amount bf siltation 1hat would have to be removed from the system in orela' to mum <br />~ <XlD<fitinns. In the first 1200 feet an estimated 3200 cubic: yards of material ranains in tbc ""'~"""l <br />. Silt up to 9.S feet deep was found in !he first large pool below the outIct. 1"bRe to fow'tUnes more silt <br />nmains in the channel below tbc first 1200 feet and is tvideot doWn to aDd below the NPI aqucdua. All the <br />large pooIa in tbc Phontnm Canyon se<:ti0ll of riVCl' ~ heavily i"'P~t'fM by silt (2-6 ft. of silt). Substrate <br />throughout the amyon is ClIlbedded IIId sp~'IIing habitat is IIOIl cxistcllt IIDtil silt is flushed from the system. <br /> <br />Aquatic; invertebrates wete qualitatMly Alllplcd IIId were dnn!;"O'M by dipterans with a few ...""M'I~ and <br />caddisf1iel appearing the farther dowasucam from the dam. SmaI1 pools near 1bc aqueducts sbowod large <br />mortalitic5 of ca4disflics due to siltation aDd low water, <br />Prcparo4 by - K J Kdunoicr, Aquatic: Biologiat <br />Oclobcr8,1996 <br />