RANGE PRESERVATION AND EROSION CONTROL. 
13 
average rate of from 0.08 to 0.10 of an inch per hour, represent the 
rapidity of rainfall characteristic of the storms throughout the sea- 
son. As a rule, storms as mild as this have little effect in causing 
run-off or erosion. 
During the rainy reason of 1916 conditions were somewhat dif- 
ferent from those of 1915. There were several storms covering 
periods of from two to five days successively. Naturally, storms 
of such duration have a greater effect in causing run-off than short 
mild storms. It was found that the rain for a time, depending upon 
the prior condition of the soil as to dryness and compactness, was 
absorbed and there was no surface run-off whatever ; but after the soil 
became completely saturated and the rainfall still continued, run-off 
occurred and with it was carried a large amount of sediment. (PI. I, 
fig. 1.) 
Table 1. — Rain f ah on erosion areas, season 1915. 
Area A. 
AreaB. 
Date. 
Upper 
gauge. 
Lower 
gauge. 
Upper 
gauge. 
Lower 
gauge. 
June 1 
0.75 
.25 
.12 
.95 
.02 
.03 
0.75 
.25 
.12 
.95 
.02 
.03 
0.75 
.25 
.12 
.95 
.02 
.03 
0.75 
.25 
.12 
June 6 
.95 
.02 
June 13 
.03 
2.12 
2.12 
2. 12 2. 12 
July 4 
.36 
.70 
.04 
.10 
.15 
.07 
.11 
.34 
.71 
.04 
.10 
.13 
.07 
.11 
.43 
1.48 
.04 
.09 
.12 
.07 
.11 
.40 
July 21 J 
1.38 
Julv 23 
.04 
July 24 
.10 
July 25 
.12 
July 26 
.07 
July 27 
.11 
1.53 
1.50 
2.34 
2.22 
Aug. 5 
.01 
.10 
.01 
.22 
.02 
.01 
.08 
.01 
.20 
.02 
.01 
.09 
.01 
.14 
.02 
.01 
Aug. 6 
.01 
Aug. 14 . . . 
.01 
Aug. 16 - 
Aug. 24 
.16 
.02 
.36 
.32 
.27 1 .30 
Sept. 2 
.15 
.65 
.11 
.05 
.26 
.18 
.03 
.39 
.15 
.65 
.12 
.05 
.21 
.18 
.03 
.29 
.13 
.62 
.10 
.05 
.32 
.18 
.02 
.36 
.13 
Sept. 3 . . . 
^63 
Sept. 4 
.09 
Sept. 7 
.05 
Sept. 8 
.27 
Sept. 11 
.18 
Sent. 13 
.02 
Sept. 25 
.44 
Total 
1.82 
1.68 
1.78 1.81 
5.85 
5.62 
5.79 
6.48 
i This was the only storm of the season to produce run-off. 
