FLOW OF WATER IE" DREDGED DRAINAGE DITCHES. 23 



in the channel, but not nearly as many as in the channel of East 

 Bogue Hasty (Plate VI, fig. 1 ; and fig. 3 C). The soil is a dark- 

 colored clay, which cracks and crumbles when dry. The slope of the 

 water surface was found to be exceedingly small, much less than the 

 grades designated in the original design of the channel. This was 

 due, no doubt, to the amount of sediment deposited in the channel 

 below the course. The values of n obtained are shown in Table 2. 



WEST BOGUE HASTY. 



For slope measurements on this channel a straight course 757 

 feet long, of quite uniform cross section at bankful stage (fig. 4 D), 

 was selected, located north of the highway bridge, about 1 mile east 

 of Litton and about 6 miles from Shaw. At the lower end of the 

 course, stakes for slope measurements were located about 50 feet above 

 the entrance of a lateral surface ditch. The gaugings for discharge 

 were made from a suspension footbridge built about in the middle of 

 the course. 



The collection of drift by the bridge below the course and sedi- 

 mentary deposits as a result of the drift and the entrance of a lateral 

 ditch just above the bridge rendered this course rather unsuitable 

 for accurate determinations of the value of n. During periods of 

 no flow a pond of stagnant water extended nearly the whole length 

 of the course, this being due to the sediment deposited near the 

 bridge. The side slopes and bed of the channel were quite regular. 

 Some weeds were found on the side slopes (Plate VI, fig. 2). The 

 soil is similar to that found in the channel of Bogue Hasty (see fig. 

 ZD for average cross section). The results of the experiments on 

 this ditch are shown in Table 2. 



EAST BOGUE HASTY. 



The course for slope measurements on East Bogue Hasty was 

 established above the highway bridge, about 2 miles east of Litton 

 and about 5 miles from Shaw. A stretch of 502 feet was selected, 

 its upper end being just below a curve in the channel and the lower 

 end just above the bridge and the entrance of a lateral ditch. The 

 discharge measurements were made from a suspension footbridge 

 about midway of the course. This course was rather short for accu- 

 rate determinations of slope but was the straightest stretch of com- 

 paratively uniform section (fig. 4 E) that could be found near the 

 lower end of the channel. 



The side slopes, and in some places the bed of the channel, were 

 covered with weeds and weed stubble, and the side slopes were 

 slightly irregular (Plate VII, fig. 1). Practically no caving took 

 place along the course, which fact was due, no doubt, to the vege- 

 tation covering the banks. The soil is quite similar to that in the 

 channel of Pecan Bayou. 



