24 - BULLETIN 832, U. S; DEPARTMENT OF AGRICULTURE. 
The values obtained for n are shown in Table 2, and, as would be 
expected from the condition of the channel, are even higher than thosé 
found for a bankful stage of Bogue Hasty. Some trouble was ex- 
perienced during the measurements, due to drift collected at the 
bridge, and this may be in part responsible for the rather high values 
obtained for n. (See fig. 3 E for average cross section.) 
DISCUSSION OF BOLIVAR COUNTY EXPERIMENTS. 
From the foregoing description of the results obtained and the 
conditions existing in each of the canals it is apparent that the most 
dependable data were obtamed for the Bogue Phalia and Bogue 
Hasty channels. ‘These results show that a value of » of about 
0.030, or slightly larger, applies to channels similar to the whole 
eaeiael of Bogue Phalia. 
The values obtained for the whole channel of Bogue Hasty, Pecan 
Bayou, and East and West Bogue Hasty demonstrate the effect of 
the conditions described upon the value of n. These values can be 
used as a guide in the design of drainage channels where like condi- 
tions can reasonably be expected to exist, due to the lack of mainte- 
nance of the channels or to the caving in of the banks. These data 
ought also to serve a useful purpose in estimating the discharge of 
old channels where like conditions prevail. 
EXPERIMENTS IN WESTERN TENNESSEE. 
These experiments were conducted during the years 1916 and 1917. 
Values of n were obtained for six different courses of the channel of 
the South Forked Deer River and for courses of the channels of the 
North Forked Deer River, Huggins Creek, Sugar Creek, and Crue 
Creek. The author was assisted in these experiments by Bz 
Andrews and A. L. Lane, junior drainage engineers of the ate 
SOUTH FORKED DEER RIVER NEAR ROBERTS. 
Gaugings of this channel were made from a single-span highway 
bridge about 1 mile south of Roberts. The slope course was 1,412 
feet long, and was located just above the gauging station. The channel 
increased gradually in size from the upper to the lower end of the 
course, there being no abrupt changes in size or shape along the 
course (figs. 5 A, Sie 6A). There was no vegetation nor any marked 
irregularities in the channel (Plate VII, fig. 2). Considerable erosion 
had taken place in this channel to which was largely due, no doubt, 
the remarkably few irregularities and the freedom from vegetation. 
As shown in Table 3, lower values of n were obtained for this channel 
than for any of the other channels in Tennessee. 
