12 
BULLETIN 114, U. S. DEPARTMENT OF AGRICULTURE. 
about 500, and from a mile above Hamilton Ridge Road to the river 
swamp the width is about 700 feet. The upper part of the drainage 
area is comparatively well drained, and largely under cultivation. 
It is rolling, with good fall to the swamp. Below the Orangeburg 
Road the land is much flatter, with little fall to the swamp above the 
Morrison Road, but with a break of 10 to 25 feet to the swamp level 
below that road. The largest cultivated tracts are along the main 
swamps where drainage is better than on higher land farther back. 
The chief need of this section is better drainage channels to bring the 
water to the main streams. 
The proposed improvement in Boggy Swamp consists of a ditch 
throughout the length of the swamp. (See figs. 2 and 3.) From sta- 
tion 0, the upper end, to station 130, the ditch should be constructed 
by hand labor, with 3-foot bottom width, 6-foot depth, and side 
slopes J to 1, giving a top width of 9 feet. From station 130 
to station 758, the lower end, the ditch is to be constructed with a 
floating dipper dredge. At the upper end of this portion there will 
be a minimum dredge ditch, and the bottom width will gradually 
increase to 30 feet at the lower end. The total fall in Boggy Swamp 
is 100 feet, varying from 17 feet per mile at the upper end, to 1.8 feet 
per mile at the lower end. (See fig. 3.) The Boggy Swamp ditch 
is not carried on to the Savannah River Swamp, but ends about 1J 
miles below the Hamilton Ridge Road. Below the end of the pro- 
posed ditch the water will overflow the swamp, but the lands adjoin- 
ing this portion of the swamp are much higher and will not be dam- 
aged, while the swamp itself is subject to overflow from the Savannah 
River and will be of little value for agriculture. 
The following table summarizes the data and hydraulic computa- 
tions for the proposed Boggy Swamp ditch: 
Table 1. — Data and computations for Boggy Swamp ditch. 
[Side slopes of ditch, J to 1.] 
Stations. 
From- 
To— 
Depth. 
Bottom 
width. 
1 
Fall. 
Ft. per 
Feet per 
foot. 
mile. 
0.00225 
11.88 
. 00325 
17.16 
.00206 
10.88 
. 00206 
10.88 
. 00051 
2.69 
. 00171 
9.03 
. 00171 
9.03 
.00171 
9.03 
.00087 
4.61 
.00087 
4.61 
. 00087 
4.61 
.00087 
4.61 
.00034 
1.80 
Com- 
puted 
Telocity. 
Watershed. Com . 
puted 
I ditch 
Area, i Run-ofE. ; capacity 
00 
40 
80 
130 
143 
260 
355 
423 
440 
531 
570 
628 
40 
80 
130 
143 
260 
355 
423 
440 
531 
570 
628 
660 
758 j 
Feet. 
Fed. 
3 
3 
3 
14 
14 
14 
14 
14 
20 
22 
24 
28 
30 
Feet per 
second. 
3.6 
3.7 
2.9 
5.15 
5.15 
5.15 
4.1 
4.15 
4.25 
4.35 
2.8 
Acres. 
600 
1,150 
1,800 
2, 000 
3,300 
4,175 
8,000 
14,800 
15,875 
17,025 
19, S50 
29,475 
31,900 
Cu.ft. 
per sec. 
Cu.ft. 
per sec. 
620 
665 
715 
835 
930 
1.005 
130 
700 
360 
630 
630 
630 
675 
740 
815 
