DRAINAGE 
low ditches, what is known as the cap- 
stan ditch plow is used in some locali- 
ties. This is an immense plow which 
makes a ditch by cutting and throwing 
the earth from the center each way, its 
action being similar to a common sod 
plow. There are wings which push the 
loose earth three feet away from the 
edge of the ditch, leaving it in a large 
continuous ridge on each side. The plow 
is pulled by two capstans, each of which 
is turned by a team of horses. The cap- 
stans are anchored ahead, and their 
winding drums are attached to the plow 
by winding ropes. This machine makes 
a clean ditch 8 feet wide at the top, 
1 foot wide at the bottom, and ordi- 
narily limited in depth to 2% feet. Used 
in Minnesota. Contract work is taken 
for about $1 per rod of completed ditch. 
The earth should be wet for this plow 
to work easily. 
Steam dredges are used for the recla- 
mation of large areas, and are of three 
different types. 1. Floating dredge; be- 
gins work at the upper end of the chan- 
nel and works towards the outlet. There 
must be sufficient water in the ditch to 
float the boat which carries the engine 
and excavating machinery. 
The excavated earth is deposited on 
each side of the ditch about 9 feet 
from the edge of the channel. This 
style of dredge is adapted to the excava- 
tion of large channels, varying from 12 
to 40 feet wide, and as deep as required. 
It has been used extensively in the Mid- 
dle West. The ditch has a shape similar 
to the letter U. 
A second type of steam dredge will 
make ditches 4 feet at the bottom, 12 
to 15 feet at the top, with a depth of 
from 4 to 9 feet and a slope of 45 de- 
grees. This machine is placed at the 
outlet and pulled up grade by means of 
a drum and cable. No water is required 
in the ditch in order to operate it. It is 
limited in its field and not much in favor 
with contractors. 
The third type of steam machine has 
similar limitations. It is constructed to 
move up grade on the surface of the 
ground in advance of the excavation. 
899 
The plant carrying the machinery rests 
upon long runners which rest upon mov- 
able rollers. The plant is moved by a 
cable, one end of which is attached to a 
Winding drum at the engine, and the 
other to a log anchored some distance 
ahead of the machine, technically called 
a “dead man.” The excavating machin- 
ery consists of two dippers which are 
filled by being pulled toward the machine 
and then dumped alternately. 
The machines described have been 
used for 15 to 20 years. The boats are 
built and the machinery mounted where 
the work is to be done. The machines 
cost not less than $5,000 each. They are 
operated by contractors, who provide 
themselves with full equipment to do the 
work by the cubic yard, under direction 
of an engineer. Contracts have been 
taken at 6 to 15 cents per cubic yard. 
The larger contracts approach the lower 
figure. Large areas are drained co-opera- 
tively, each farmer benefited paying a 
share. In most states the main canal 
is subject to the drainage law. 
The course of ditches and streams is 
crooked in flat land, but artificial drain- 
age channels may improve and straight- 
en them. Ditches on rolling land may 
differ from those on flat lands by having 
narrow bottoms, since the velocity of 
flow is sufficient to scour and deepen 
them. The outlets of tile in rolling land 
may be shallower where there is a mark- 
ed rise in the ground surface above the 
outlet. 
Cross-Section and Behavior of Ditches 
It has been found by experience that 
ditches may be constructed with sides 
more nearly vertical than was formerly 
thought practicable In stiff loams and 
clays it is not desirable to cut sides 
with slopes greater than 1-1. Loams, 
144-1. Ditches made with a floating 
dredge have a slope of ahout 114-1. 
Weathering and erosion will in any case 
change the slope, so it is of greater im- 
portance to secure ample bottom width 
in order to allow this change than to 
attempt to make the exact slope desired 
and to expect it to remain. 
The excavated earth, or waste bank, 
