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<br />2,000 cubic feet per second, the optimum channel capacity was found
<br />to be 1,500 cubic feet per second. The selected capacity will trans-
<br />port the entire flow of the Pecos River about 9605 percent of the
<br />time and will pass about 74.3 percent of the average annual volume of
<br />fl01>l.
<br />
<br />The channel was designed to obtain, insofar as possible, the
<br />optimum combination of requirements for a stable channel in alluvium,
<br />for sediment transport characteristics, and for practical and econom-
<br />ical construction under contr~lling conditions of streamflow, total
<br />sediment load, soil characteristics, and available gradeo The
<br />hyd:-aulic properties required to permit the maxinrJJ1l rate of flow of
<br />1,500 cubic feet per second with a coefficient of roughness of 0.025
<br />were determined by' the use of the Nanning formula. The properties
<br />required to transport the portion of the total sediment load which
<br />would be diverted to the channel were determined by the modified
<br />Maddock Equation, The requirements for stability of the channel in
<br />the types of soils through which it must be constructed were met by
<br />application of the principles of tractive force, The channel and
<br />floodHay levee were desi.gned to ootain the most favorable balance
<br />bet\.een the volume of material excavated from the co:weyance channel
<br />and the volume of embankment material required to construct the levee,
<br />
<br />The design of the channel hea.ding was patterned after the
<br />heading for a similar channel, in the Rio Orande Basin, which is
<br />operating satisfactorily. The heading is a concrete structure with
<br />four corregated metal pipe outlets, controlled by screwolift gates,
<br />
<br />Construction Costs
<br />
<br />The following tabulation swrunarizes the estimated
<br />construction costs of the project on the basis of September 1954 price
<br />
<br />Rights of way, 0 , . , , . . . , . .0 o. ~115,600
<br />Highway Revision, . . . , . , 0 . 0 . . ,. 129,000
<br />Clearing Lands, . 0 _ v . . . . 0 . 0 . .. 582,200
<br />Heading . 0 . . ~ . . . . . 0 0 Q . ~ ~ 0 0 135,000
<br />Levee and Conveyance Channel ..,.... 522,300
<br />Pilot Channels ". 0 , . 0 . 0 . . . ., 9,900
<br />Floodway and Levee Jetty Protection 0 . ,. 72,000
<br />Channel Stabilization . , . . . 0 0 . . ,. 144,000
<br />Access and Operating Roads ..... 0 .. 100,000
<br />General Property. . , . . . . . . , . . . 0 196,000
<br />Transitional Development o. 0 , , . . .. 30,000
<br />Project investigations .. 0 . , , . 0 ., 1~?~000
<br />TarAL 0........ a . . . . 0 0 0 ~2s1bl,OOO
<br />
<br />QEeration and Maintenance Costs
<br />
<br />for
<br />and
<br />
<br />The operation and maintenance costs of the project provide
<br />the necessary general property, operation and maintenance personne'
<br />materials, services, and contract maintenance items. The estimate
<br />
<br />o
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