Laserfiche WebLink
0 <br />0 <br />t <br />1 <br />2 <br />3 <br />4 <br />5 <br />6 <br />7 <br />8 <br />9 <br />10 <br />11 <br />12 <br />13 <br />14 <br />15 <br />16 <br />17 <br />18 <br />19 <br />20 <br />21 <br />22 <br />23 <br />24 <br />25 <br />26, <br />27 <br />28 <br />now trapped behind the dam "). Absent the upstream sediment load, the lower Colorado <br />River depends on tributary sand inputs to provide the shoreline sanctuaries for young chub. <br />Exh. 11 (SCORE) at 18; Exh. 3 (1994 BO) at 22.5 <br />Reclamation's operation of Glen Canyon Dam -- specifically, how water is released <br />-- is adversely impacting critical habitat for the humpback chub in the Colorado River. <br />Operations affect river flows, shoreline habitats, and temperatures. Exh. 3 (1994 BO) at 21- <br />24; 26 -31. Before Glen Canyon Darn was built, Colorado River "[f]low[s] varied greatly <br />between seasons, from peak flood flows in May or June ... to low flows in January." Exh. <br />13 (2007 BO) at 20. At the same time, the "daily variation in [flows] was relatively small." <br />Id. Further, river temperatures were warm before the Dam. Id. <br />Today, Dam operations are disrupting the timing and volume of seasonal river <br />flows, destroying shoreline habitats, and keeping water temperatures cold. They provide "a <br />more stable environment in all ways except for daily variation in discharge." Exh. 13 (2007 <br />BO) at 20. Rather than seasonal flows, Reclamation's operations have "reduced the <br />magnitude of spring peak flows and increased the magnitude of summer- winter base <br />flows." Exh. 9 (2002 Recovery Goals) at 19 ( "Spring peak flows have been reduced by <br />about 80% and summer- winter base flows have been increased by about 30 %. "). Daily <br />fluctuating flows, which maximize revenues associated with the demand for "peaking" <br />power, cause river flows to vary greatly during the day. Exh. 13 (2007 BO) at 20 ( "to <br />maximize the value of hydropower generation, releases from Glen Canyon Dam are <br />typically lowest in the morning and peak in the early evening. "). Specifically, the "daily <br />change in discharge (8,580 cfs [cubic -feet per second]) is now approximately 15 times <br />greater than pre -dam (542 cfs)," which causes dramatic rises in the river of up to over six <br />feet a day. Id. (emphasis added). <br />5 The Dam's presence has also fragmented habitat in the Colorado River system and <br />isolated remaining chub populations, which prevents chub movement between populations <br />and the exchange of genetic material that could allow the species to adapt to a changing <br />environment. 59 Fed. Reg. at 13374. <br />Memorandum in Support of Pls.' 7 <br />Motion for Summary Judgment <br />