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<br />A.SCOUR <br />15 <br /> <br />10 <br /> <br />-5 <br /> <br />-10 <br /> <br />I- -15 <br />w <br />w <br />u.. <br />z -20 <br /> <br />z <br />o <br />j:: <br /><( <br />> <br />W <br />...J <br />W <br /> <br />B. FILL <br />15 <br /> <br />10 <br /> <br />-5 <br /> <br />-10 <br /> <br />-15 <br /> <br />-20 <br />-10 <br /> <br /> <br />".,.- <br />/' <br />/' <br />/' <br />~'_. <br />,/' <br /> <br />5 <br /> <br />. <br />. <br />~.. <br />1\\ .,.../ ",' <br />. \\ " .......,.' <br />I \. -,' <br />.t "'..' <br />......'---....... " ...." <br />~. '" ......,' , <br />. , <br />. , <br />. , <br />, .' <br />\ <br />\ <br />, ,../ <br />\ -'- <br />/' <br />,,,.,.-' <br /> <br />..' <br /> <br />..' <br />................ <br /> <br />JANUARY 7, 1993- <br />5,530 cubic feet per second <br /> <br />JANUARY 13,1993- <br />1,390 cubic feet per second <br /> <br />JANUARY 18,1993- <br />5,170 cubic feet per second <br /> <br />FEBRUARY 8,1996- <br />16,900 cubic feetper second <br /> <br /> <br />.......------------ <br />....- <br />......... ",""'" ---.---.- <br />/' <br />/ <br />/' <br />/' <br />,""'- <br />/ <br />/' <br />/' <br />.-oJ'" <br />, / <br />\ ./' <br />. ,-.-........... <br />\".,.-' <br /> <br />gaging station, and 390 ft upstream from the <br />gaging station, Historical changes to the PZF were <br />compiled and are presented (fig,6). <br />Cableway cross sectlon.- The cross <br />section at the cableway scoured during increasing <br />discharge and filled as discharge decreased (figs. 2 <br />and 3; table 1). During the discharge measurement <br />of5,530 ft3/s on January 7, 1993, the cross section <br />generally had a wide and shallow shape (fig, 3). <br />The peak discharge of 52,500 ft3/s occurred on <br />January 8, 1993 (fig. 2). Following this peak, data <br />from the next discharge measurement show that <br />the right portion of the channel filled about 3 ft, <br />probably during the recession of the flood peak <br />(fig. 3). Maximum scour was measured on <br /> <br />o <br /> <br />5 <br /> <br /> <br />Reference <br />elevation <br /> <br />o <br /> <br />....,.. <br />.."'.... " <br />........:;---...........,/ <br /> <br /><II' ..... ......;:....-'" <br /> <br />, \,..' 'l'/ <br /> <br />",,' " I <br />" / .... <br />\ ,- <br />.... <br /> <br />-- -- ... \ <br /> <br />FEBRUARY 8,1993- <br />16,900 cubic feet per second <br /> <br />FEBRUARY 10,1993- <br />4,470 cubic feet per second <br /> <br />FEBRUARY 20,1993- <br />9,940 cubic feet per second <br /> <br />FEBRUARY 21,1993- <br />3,160 cubic feet per second <br /> <br />10 <br /> <br />50 <br /> <br /> <br />170 <br /> <br />70 90 <br />STATION, IN FEET <br /> <br />110 <br /> <br />130 <br /> <br />150 <br /> <br />Figure 3. Cross section from discharge measurements at cableway, Agua Fria River near Rock Springs, <br />Arizona, 1993. A, Scour, January 7 through February 8, 1993. B, Fill, February 8-24, 1993. <br /> <br />February 8 during a discharge of 16,900 ft3/s. <br />Between January 18 and February 8, the width in- <br />creased slightly in relation to the reference eleva- <br />tion, and the hydraulic radius more than doubled. <br />Most of the increase in cross-sectional area, there- <br />fore, was accounted for by the increase in depth. <br /> <br />After February 8, increases in discharge <br />.caused an increase in channel scour, and decreases <br />in discharge caused the channel to fill (fig. 3). <br />Data from the discharge measurement made on <br />February 10 at 4,470 ft3/s show the cableway cross <br />section filled with as much as 15 ft of sediment <br />after February 8. The final 1993 flood peak of <br />30,400 ft3/s occurred on February 20. A discharge <br /> <br />Results 9 <br />