56 BULLETIN 832, U. S. DEPARTMENT OF AGRICULTURE. 
MAIN CHANNEL NEAR FELLSMERE. ~ 
The slope course on this channel was straight and was 2,000 feet. 
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long. The gauging station was located about 100 feet below the 
downstream end of the slope course, which was about 3 miles north’ . 
of Fellsmere. The gaugings were made from a footbridge about 10 feet 
upstream from the county highway bridge and supported by suspen- 
sion brackets from the piling of that bridge. The channel was quite 
uniform in cross section, there being only one rather abrupt variation, 
which occurred near the upper end of the course (figs. 12 A, and 12 B). 
The bottom of the channel was broad and regular and quite evenly 
covered with sand. The side slopes were fairly regular and prac- 
tically free from vegetation in the lower part of the channel, but 
rather irregular and covered with vegetation in the upper part (fig. 
11 A, and Plate XVIII, fig. 2). With the exception of measure- 
ment 10, Table 6, for which the highest value of n was obtained, the 
measurements were made for stages almost wholly in the lower and 
better part of the channel. For the same part of the channel the 
values of n obtained during 1917 were somewhat lower than those 
obtained during 1916. This might be attributed to the fact that the 
cross section had become somewhat more uniform between the dates 
of the two sets of measurements, as appears from the graphs shown 
in figures 12 A and 12 B. 
MAIN CHANNEL NEAR VERO. 
Gaugings of this channel were made from a suspension footbridge 
near Vero. The upper end of the slope course, which was 1,000 feet 
long, was located about 40 feet downstream from the gauging station. 
The bottom was sandy, and there were several flat, broad sand bars 
in the channel during low water (Plate XIX, fig. 1; and fig. 11 B). 
There was some vegetation in the channel, which can be seen in the 
view just referred to. The cross-sectional area of the channei was 
quite uniform except for the lowest measurements, Nos. 11 and 72 (see 
Table No. 6 and figs. 12 C and 12 D). The side slopes for the three 
low-stage measurements made during 1916 were fairly regular, but 
for the three higher stage measurements, Nos. 14, 15, and 19, made at 
about half-bankful stages, the slopes were quite rough and irregular, 
owing to the fact that large lumps of the bank had sloughed off. The 
values of m obtained indicate that the retardation to flow was much 
greater in the upper part than in the lower part of the channel, which 
was apparently due to the caving of the banks in the upper part of 
the channel. 
MAIN CHANNEL NEAR FORT PIERCE. 
Gaugings of this channel were made from a suspension footbridge 
located about 3 miles west of Fort Pierce. The upper end of the 
slope course, which was 1,032 feet long, was located about 25 feet 
