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564 10000 1000 m 8lm ..8: 100 "'~ W:I: ~~ 10 ~~ WZ <11- ~!Z ~g 0.1 :>" 0< 0.01 " < 0.001 TOPPING ET AL: COLORADO RIVER SEDIMENT TRANSPORT, 2 FRONT OF UPSTREAM (UNIMODAL) PORllON OF SEPT. 1998 SEDIMENT WAVE :0+-- DOWNSTREAM (SECONDARY-MODE) PORTION OF----" SEPT. tgge SEDIMENT WAVE .... ....... ....~... $ILT&CLAY ---.- 0.0625-0.077 mm SAND -0- Q.on-O.088 mm SAND ___._0.088-0.105 mm SAND -0-- 0.105-0.125 mm SAND 0.0001 a) 0 '0 20 30 40 50 60 RrvER MILE 10000 1000 ....~m SILT & a..AY m ~ O.062~.077 rrm SAND m m -- 100 --0- 0.077-0.088 rrm SAND ~ffi -+- 0.088-0.105 mm SAND ~1C " " 10 -0-0.105-0.125 nvn SAND <w "Ii: zw -<II !zo; h... :>!z 0.1 ii5 .-.... " 0.01 < 0.001 0.0001 b) 0 10000 1000 m ;;g: 100 g:- ~:I: >-0 10 <'" ,,< " o;z !z;: :>z 0.1 0:> ,,0 <" < 0.01 0.001 0.0001 c) 0 10 20 30 RNER MILE 40 50 60 .... .... ....... .......~......... .m)(:... SILT & CLAY (me8l1 value = 0.74) ---.- 0.0625-0.017 mm SAND (mean value = t.n -0- 0.077-0.088 mm SAND (mean value = 2.1) --+- O.~.105 mm SAND (mean value", 3.6) --0- 0.105-0.125 mm SAND (mean value = 5.0) x.... ..... ...... ....... ............ 10 20 30 RIVER MILE 40 60 50 Figure 15. Changes in the amount of silt and clay and four size classes of finer sand on the bed of the Colorado River in Marble Canyon associated with the September 1998 Paria River floods. These changes are shown only for the locations that were sampled on all three trips (in March 1998, September 1998, and May 1999). (a) Ratio of the amount of each size class composing the tine sediment on the bed following the Paria River floods in September 1998 to the amount of each size class that composed the fine sediment on the bed in March 1998. Impact of the tributary-flood sediment on local grain-size decreases downstream is shown. This effect is most pronounced for intermediate grain sizes, since finest sediments (silt and clay) tended to bypass this reach and coarser sizes (>0.105 mm) had not yet greatly arrived by the time of the September 1998 sampling trip. (b) Ratio of the amount of each size class composing the fine sediment on the bed in May 1999 (8.5 months after the Paria River floods) to the amount of each size class that composed the fine sediment on the bed in September 1998 (immediately following the Paria River floods). (c) Ratio of the amounl of each size class composing the fine sediment on the bed in May 1999 (8.5 months after the Paria River floods) to the amount of each size class that composed the fine sediment on the bed in March 1998 (6 months before the Paria River floods). The mean values of the ratios for each size class are shown in parentheses.