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<br />. <br /> <br />. <br /> <br />'d'~(.. '! <br />..~':'.J <br /> <br />scour and sediment and debris deposition. Dama~es include tangible and <br />intangible losses. Tangible damages subject to monetary quantification <br />include physical damage to land and improvements, crops, emergency costs, <br />and loss of business and other income, both in and adjacent to flooded <br />areas. Intangible losses are not susceptible to monetary evaluation <br />and inc lude danger to human life, human discomfort, inj ury and exposure <br />during floods, creation of conditions detrimental to health and security, <br />and interruption of normal community activities. Physical damages in- <br />clude cost of cleanup, damages to buildings and contents, and damage to <br />other improvements and property. <br /> <br />77. The Barrier Dam-Pueblo Flood"ay project provides a high degree <br />of flood protection for the major portion of the city of Pueblo; ho"ever, <br />an appurtenant feature of this improvement, the] evee on the left bank <br />of Dry Creek above the Denver and Rio Grande Western railroad bridge, <br />docs not provide the same high degree of flood protection as the main <br />flood"ay. Barrier Dam, a flood detention structure located at- the <br />Pueblo Damsite, \1ill be replaced by Pueblo Dam and Reservoir. The <br />Pueblo Floodliay together \-lith rC;lulatio!l provided by Pueblo Reservoir <br />\.Jill protect the city of PUt:blo against [loads in exce5S of st~ndard <br />project flood cacnitude. There are RIsn severa] important developments <br />in the flood pl::in nc,n the city \-Ihie!, at present have some flood pro- <br />tection but not to the degree provided by the main flood"ay levees; <br />Ilamely, the two water \-;odos at the \-:estern e-dge of Pueblo upstream <br />from the flood"ay and the se"age treatment plant at the eastern edge <br />of the city belOl; the flood"ay. <br /> <br />78. Do"nstream from Pueblo, the Arkansas River flows through a <br />broad valley highly developed for agricultural purposes. Several fac- <br />tors contribute to complex problems in the valley bet"een Puehlo and <br />John t-lartin Reservoir. The normal streamflo" is diverted and rediverted <br />for irrigation uses. Long reaches of the river arc often dry, or nearly <br />so, and irrigation canals parallel to the river frequently carry more <br />"ater than- ffo';5 tllrough -the riv-er-ch-ai1nel~ - Tribut-ary streamscon~ - - <br />tribute little to the perennial flo" of the river but frequently flood, <br />and carry large quantities of sediment into the main stem. Flo"s <br />remaining in the main stem after diversion for irrigation are not <br />adequate to maintain a channel through sediment deposits. The result <br />is an acceleration of aggradation which reduces the channel capacity, <br />causes channe I changes, and creates obstruction to flow. Consequent ly, <br />flooding becomes more frequent and severe "ith increasing adverse ef- <br />fects on agricultural and other development throughout the reach. <br />Irrigation interests have indicated that the river channel aggraded <br />four to six feet in one ten-year perind. To maintain their diversions <br />in operating condition, it has been necessary to raise the crests of <br />diversion dams every fe" years. The aggradation below the diversion <br />diminishes the effective head available for bypassing sediment and <br />debris through the structure he fore it enters the canals and thereby <br />increases the cost of maintenance of the irrigation systems. Aggradation <br />also contribute, to drainage problems because the higher streambed levels <br />cause higher ground water tabl"s. <br /> <br />28 <br />