- 
49, BULLETIN 832, U. S. DEPARTMENT OF AGRICULTURE. 
is very similar to that of Allen Creek, and the values of n obtained, 
as given in Table 4, are practically the same as those obtained for 
Allen Creek. 
BOYER RIVER. 
Gaugings of the Boyer River were made at the Lincoln Highway 
bridge about 1 mile from Missouri Valley. The downstream end of 
the slope course was 197 feet above the bridge. The length of the 
slope course was 868 feet. A view ot the slope course looking 
upstream is shown in Plate XIII, figure 2. The downstream slope 
posts are barely visible on the left-hand side of the view, just above 
Distence along Slope Course in fee? 
500 A 
ALLEN CREEK 
S 
is Average Maximum Depth 
) 7.1 
% 
S 3 
S2 , B 
& WILLOW CREEK 
q 
Se 74 
C 
BOYER RIVER 
| 
12.2 
D 
PIGEON CREEK 
12.4 
Per cent Variation from A 
LG" 
Fig. 8.—Graphs for experiments in western lowa, showing per cent variation from average cross sectionai 
area for all cross seetions along slope course. 
the break in the bank. It can be seen that above this break in the 
bank the course of the channel is straight and fairly uniform in cross 
section (fig. 8 C). The sides of the upper part of the channel stand 
at a slope of about 1 to 1 (see fig. 7 (). The soil in the upper part 
of the sides of the channel consists of a dark loam and in the lower 
part it is a hard yellow clay. The channel is practically free from 
any iorm of vegetation, which condition is largely due to its rapid 
enlargement caused by erosion. Since the channel was constructed, 
in 1910, it has enlarged to almost double its original size. 
During flood stages the condition of the channel was very similar 
to that described for the Allen and Willow Creek channels. After the 
te , wih. 
