[ 37 ] 
The Silt 
Problem and Storage Reservoirs. 
5 
For this set the top samples carried the most sediment, on the average. 
It requires only a casual glance at the turbid water to see that the cross- 
currents are constantly changing and. streaks of very muddy water alter- 
nate with less heavily charged portions. 
For eight sets of four samples each collected from the Wichita River 
the means at different depths were as follow^: 
From top .3.420 per cent. 
From one-third depth .3.370 per cent. 
From two-thirds depth 3.370 per cent. 
From bottom 3.340 per cent. 
Mean 3.375 per cent. 
For one set taken with the sampler on July 21, 1900, the greatest 
amount of silt was carried at the bottom, though on the same afternoon 
the top sample showed the larger amount. Only two samples could be 
taken at this latter hour, however, because the rapid current made it 
impossible to get the sampler to the bottom of the river. 
For six sets of three samples each the following average results were 
obtained : 
From top 1.845 per cent. 
From mid-depth 1.777 per cent. 
From bottom 2.047 per cent. 
Mean 1.890 per cent. 
The foregoing results are all based upon the volumes of silt found at 
the end of one week. Professor Goss has sent me the following results 
for the quantities of silt carried by the waters of the Rio Grande on three 
occasions, the samples having been collected at Earlham Bridge, and 
which were allowed to stand one month before being measured : 
Collected. 
Percentages of silt carried by the water. 
Top. 
One-third 
depth. 
Two-thirds 
depth. 
Bottom. 
Mean. 
July 23, 1899 
26.25 
26.25 
27.25 
25.63 
26.34 
August 13, 1899 
33.75 
33.75 
33.13 
34.37 
33.75 
December 4, 1899 
5.00 
4.38 
4.37 
3.75 
4.38 
For these three sets the percentages were computed from the depths 
sent me by Professor Goss. The first and second show enormous amounts 
of sediment, due to the fact that the flood had come from rushing tor- 
rents that had abraded the mountain sides as the water came down. 
Much of this sediment seems to be deposited before the water reaches 
El Paso, for in the samples I secured from that point the amount of silt 
