48 



BULLETIN 832, U. S. DEPARTMENT OF AGRICULTURE. 



TURKEY BRANCH. 



A straight course 200 feet long was selected for slope measurements 

 on the Turkey Branch channel just above the Atlantic Coast Line Rail- 

 road southwest of Pembroke. This channel is small and was hand- 

 dug (Plate XVI fig. 1 : and fig. 9 A). At the time of the experiments 

 the channel was very uniform in cross section for a bankf ul stage ; it had 

 regular side slopes and was free from growth of any kind. The values 

 of n obtained were only for very low stages. As may be seen from 



.Table 5, the average 

 maximum depth for 

 the channel at bankful 

 stage was 5.0 feet, and 

 only 0.95 foot for the 

 highest stage for which 

 n was determined. The 

 cross sectional area of 

 the lower part of the 

 channel varied consid- 

 erably in size (fig. 10 

 A). 



BACK SWAMP. 



A straight course of 

 channel 250 feet in 

 length was used for 

 slope measurements 

 on the Back Swamp 

 channel. It was lo- 

 cated just west of the 

 Sunday Ford Road and 

 about 8 miles west of 

 Lumber ton. At the 

 time of these meas- 

 urements the channel 

 was quite uniform in 

 cross section, and the 

 side slopes were quite regular (fig. 10, B). The side slopes have 

 been eroded considerably so as to be nearly vertical, leaving a mat 

 of overhanging ragged roots on either bank. Owing to a compara- 

 tively swift current, there were no weeds, grass, or other vegetation 

 on the bottom or side slopes, but there were a number of large tree 

 roots in the channel. Plate XVI, figure 2 ; and figure 9 B, show the 

 condition and average cross section of channel, and Table 5 shows 

 the values obtained for n. Of the five channels for which experi- 

 ments were made, this is the only one where a value of n was determined 

 for a near bankful stage. 



^^^^m^^'i^W M9'yAjW4^M 



Fig. q.— Average cross sections of channels for experiments in 

 North Carolina. 



