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<br />'i <br />~ <br />"I <br /> <br />post-Dam Period <br /> <br />In contrast with the Pre-dam period, <br />construction with fluctuating flows were <br />pre-dam. <br /> <br />* Less drought resistant forms like the mesquite began to <br />decline in the Old High Water Zone due to the lack of 100,000 <br />cfs flows which would periodically provide water. These <br />species are being replaced by upland plants such as the barrel <br />cactus and cholla cactus. <br /> <br />~. <br /> <br />conditions after dam <br />markedly different from <br /> <br />" <br /> <br />* New riparian vegetation growths between 30,000 and 45,000 <br />cfs flow stages increased under high fluctuating flows by <br />nearly 2,000 acres in the first 20 years. This doubling in <br />area of riparian vegetation is in stark contrast to the <br />overwhelming loss of riparian habitat occurring in nearly all <br />other southwestern rivers. <br /> <br />'.,1 <br />::1 <br /> <br />* Wet and dry marshes developed for the first time after dam <br />construction due to regular wetting. <br /> <br />* There was a marked increase in diversity and numbers of <br />birds, mammals, reptiles, and insects using the riparian <br />corridor after dam construction and under fluctuating flows. <br /> <br />'< <br /> <br />'. <br /> <br />'. <br /> <br />* Little direct effect of fluctuating flows on nesting birds <br />was recorded under historic dam operations. <br /> <br />':.1 <br />" <br /> <br />* Wintering waterfowl numbers steadily increased after dam <br />closure. Nesting of waterfowl along the river is a novel <br />phenomenon seen only since 1982. <br /> <br />* Peregrine falcon numbers increased dramatically after the <br />dam and are now estimated at about 96 breeding pairs. <br />Increased algae productivity in the river as a result of clear <br />water releases from the dam translated into more insects, more <br />swifts and swallows and, therefore, more falcons. <br /> <br />* The increased production of algae provided fuel to run <br />ecosystems downriver to Lake Mead including food for trout and <br />Humpback chub and fluctuating flows caused this downstream <br />distribution. <br /> <br />-," <br />.~:"I <br />~~. <br />;~-:. <br />,. <br /> <br />* Adult Humpback chub condition in the Grand Canyon under <br />fluctuating flows became better than the condition of other <br />Humpback chub in more "natural" hydrologic situations in the <br />Colorado River. <br /> <br />* Cold water releases from the dam have created conditions <br />which were too cold for successful spawning of Humpback chub <br /> <br />3 <br />