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<br /> <br />N 0.8 <br />0 <br />'00 <br />W <br /> ~ <br /> ~ 0.6 <br /> . <br /> " <br /> !'3 <br /> ~ 0 <br /> H <br /> ~ 0,4 <br /> '" <br /> Iil <br /> j <br /> ~ 0.2 <br /> ~ <br /> <br /> <br />~ <br />'" <br />00 <br />'0< <br />. <br />o <br />M <br />~ <br />~ <br /> <br />Slope=.0053 <br />r2 ::: .99 <br /> <br />~ <br />,~ <br /> <br />o <br />o <br />'0< <br />. . <br />" <br />00 <br />0", <br />"'~ <br /> <br />~ <br />~ <br /> <br /> <br />o <br /> <br />Slope=.0007 <br />r2 = .83 <br /> <br />0Flume 111 Dried Sediment Sample 8/26/76 <br /> <br />. <br />i;' <br />'" <br />"; <br />~ <br />~ <br /> <br />.Q)Flume #1 Wet Sediment Sample 9/9/76 <br />Slopes in gm/minO.5 <br /> <br />o <br /> <br />50 <br /> <br />100 150?00 <br />SQUARE ROOT OF TIME (minO,5) <br /> <br />250 <br /> <br />Figure 4.22. Salt dissolution from macrochannel bedload material. <br /> <br />I <br /> <br />replications in the four samples in each set, <br />the two slopes and the breakpoint time <br />were calculated. The results are listed in <br />Table 4.12. Comparisons were made among <br />sediment samples of the total salt release at <br />1) the end of the steep portion of the curve <br />(Figure 4.22), and 2) at l1.S days. A <br />t-statistic was used to test the null <br />hypothesis that the accumulated conductivity <br />means were equivalent with the results listed <br />in Table 4.13. Drying the sediment signi- <br />ficantly increased the salt released during <br />the steep portion of the 'curve. However, <br />after 11.5 days there was no significant <br />difference in the cumulative salt release for <br />the two sample treatments. <br /> <br />Soil salinity sensors were installed in <br />the macrochannel on August 15, 1976, and <br />monitored weekly (Figure 3.3). The sensors <br />had been saturated with a 4000-~mhos/cm (at <br />2S'C) solution of calcium and sodium chloride. <br />The manufacturer of the sensors, Soil Mois- <br />ture Equipment, Inc. (1976), recommend the <br />following operating ranges for the s"ensors: <br /> <br />1. A soil moisture tension range of <br />from 1 to lS bars. <br /> <br />2. A conductivity range of from 500 to <br />30,000 ~mhos/cm at 2S'C. <br /> <br />, <br /> <br />Table 4.12, <br /> <br />Estimated <br />Salt @ Time <br />Breakpoint <br /> <br />Wet Sediment <br />Samples <br />8/26/76 <br />X 0,094 <br />S 0.081 <br /> <br />Dried Sediment <br />Samples <br />8/26/76 <br />X 0.341 <br />S 0,071 <br /> <br />Wet Sediment <br />Samples <br />9/9/76 <br />X 0.070 <br />SO,023 <br /> <br />300 <br /> <br />K2 <br />gms/ <br />minO.S <br /> <br /> <br />KI <br />gms/ <br />minO.S <br /> <br />Ll <br /> <br />Mean salt dissolution rates for <br />macrochannel sediments. <br /> <br />Estimated <br />Salt @ Time <br />It - 125 <br /> <br />0.672 <br />0.236 <br /> <br />0.705 <br />0.133 <br /> <br />0.740 <br />0.176 <br /> <br />minO.S <br /> <br />0.00462 <br />0.00226 <br /> <br />0.00384 <br />0.00120 <br /> <br />83.38 <br />1.00 <br /> <br />0.00670 <br />0.00156 <br /> <br />92.41 <br />10.36 <br /> <br />4 replications for each group of samples <br />K1' L1. K2 defined on Figure 4.16 <br />*No break observed in curve <br /> <br />41 <br /> <br />. <br /> <br />. <br /> <br />0.00107 <br />0.00062 <br /> <br />0.00156 <br />0.00110 <br />