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11~~,:~ 001591 STATE OF COLORADO v\. ,1/ OFFICE i~IJ1.E~Xt<a4lIY& '~Nl?ftlb Long Hollow confluence to Cherry Creek confluenc / Departme'l\~etiiffifl~,~u~ckled dace, flannelmouth sucker, bluehead sucker, mottled sculpin 1313 Sherman Street"-~q6m i1'8d-:' 'I h b (M'll 1995) Fl 'h' h 'd' 11 d b Denver c&&~dWW~w roun tal CUI er, . ows III t IS reac peno Ica y ry up, Phone:' (3Q1a600el:fbh are able to re-colonize by moving upstream from below Long Hollow C TOD: (303J.MP~"W..esently flows year-round due to irrigation return flows.' DEPARTMENT OF Fax: (303) 86'~-r-tt:r.L - - .---'- NATURAL Reach 3: Long Hollow Creek and its tributaries: speckled dace, bluehead sucker, RESOURCES flannelmouth sucker. A CDOW stream survey in 1975 showed speckled dace and Bill Owens bluehead sucker were present in Long Hollow Creek. A CD OW stream survey in 2QJi~~~eorge showed flannelmouth sucker were present in Government Draw. Recent fish surveyxecutive Director information is lacking for Long Hollow Creek at the proposed reservoir site. During the recent drought, flows in Long Hollow Creek have been the onl erennial source-or water or t e lower La Plata River. Long Hollow Cree could be a refugium for native fishes, Additional fiSllsurveys are needed for Long Hollow Creek and Government Draw at the site of the proposed reservoir. i3 A if\J.'u1eS Lower portion of Reach 3: It IS assumed the native fishes inhabiting the -112 mile reach from Long Hollow Dam site to the confluence with the La Plata River would be permanently fostdue ~servo' ---=-"ons.' u "er, I IS assumed that all natIve Ishes 'Currently inhabiting the proposed reservoir basin (lower Long Hollow Creek and Government Draw) would be permanently lost when stream habitat is inundated. . \ ~ \ LJ?, Jt; -~ .) " ~?':.. ~:~'\pI(C tJ- -< ~. .....-'.. r.'" .~......... J/' ..-- II. La Plata River instream flow issues and recommendations. Hydrology: Lack of long term hydrological data for Long Hollow Creek makes it difficult to assess the total impact oftms project. In the BA, major assumptions for modeling the impacts of Long Hollow Reservoir are based on only ten years of stream gage data (1988 to 1998). It is generally recognized that irrigation return flows contribute significantly to base flows in the La Plata River below the Cherry Creek and Long Hollow confluences. For example, in January, 2004, Long Hollow Creek contributed about 50% of the base flow in the La Plata River from Long Hollow to the state line. Hydrologic impacts of the proposed project: A description of the anticipated impacts of the h proposed reservoir to native fishes is found in the BA: "Typically, stream flow will decrease II: during the non-Compact period from December 1 st through February 15th and will be equal to or 1 greater than the pre-reservoir stream flow during the remainder of the year... .Potentially l significant adverse impacts may result to the state sensitive roundtail chub and flannelmouth ~ sucker. . .. Reduced base flows during the winter months (the non-compact period from fi December I-February 15) may result in habitat loss for roundtail chub and increased'/" vulnerability of fish to freezing temperatures and predation from birds", .Native fish may not \1 withstand., ,the spiking flows to the La Plata River from the reservoir to meet compact , demands, . , ." Instream flow studies and recommendations: Flows to protect native fishes in the lower La Plata River have been recommended by various resource agencies. Board of Land Commissioners. Division of Minerals & Geology/Geological Survey Oil & Gas Conservation Commission. Colorado State Parks. Divisibn of Forestry Water Conservation Board. Division of Water Resources. Division of \^iildlife