36 BULLETIN" 300, U. S. DEPARTMENT OF AGRICULTURE. 
large ditches the top width is too great to permit the use of a ma- 
chine of this type. The scraper machine of the rotary type, operat- 
ing from the top of one waste bank, has also been used for cleaning 
out old ditches. With this kind of machine the banks of the ditch 
can be trimmed. However, the machine must first level down the 
old waste bank sufficiently for it to travel over. An orange-peel 
bucket, instead of the scraper bucket, has also been used on the drag- 
line machine for cleaning ditches. With the drag-line excavator it 
is unnecessary to remove bridges, which item effects a considerable 
saving in cost of cleaning ditches on a large project. The rotary 
type of scraper excavator is probably the most efficient machine for 
cleaning ditches. 
A small centrifugal pump operated by gasoline power and mounted 
on a small hull has been used in cleaning out some ditches in Iowa. 
This device is illustrated in Plate IX, figure 2. The pump, which 
has a 5-inch suction pipe and two 5-inch discharge pipes, is operated 
by a 48-horsepower internal-combustion engine which starts on motor 
spirits and runs on kerosene. The whole equipment was mounted 
on a hull 28 feet long, 5 feet wide at the bottom, 10 feet wide at the 
top, and about 4J feet deep. Immediately in front of the hull were 
placed five cutter wheels, each 3 feet in diameter and weighing 100 
pounds. These cutter wheels were operated by power obtained 
from the engine. The end of the suction pipe was 5 feet long and 2 
inches wide and was placed about 2 feet behind the cutter wheels. 
Half of the material was discharged on each side of the ditch, beyond 
the waste bank. The dredge cleaned from. 250 to 300 feet of ditch 
in a day of 10 hours. The excavation amounted to about 1J cubic 
yards of earth for every linear foot of ditch. Three men were required 
to operate the dredge. By taking down one discharge pipe and turn- 
ing the other lengthwise of the ditch the dredge could easily pass 
under the bridges. Four men could dismantle the dredge in 2 days 
and set it up in 5 days. The complete cost of the plant was $3,000. 
For removing sand and silt from ditches this type of machine is 
excellent. The dredge works downstream and must have consider- 
able water. The average cost of operation per day was as follows: 
One engineer $3. 00 
One assistant 2. 50 
One helper 2. 00 
Twenty gallons kerosene, at 10 cents 2. 00 
Total cost per day 9. 50 
Based on 200 feet of ditch cleaned, the excavation per day would 
be 300 cubic yards, and cost per cubic yard about 3 cents, exclusive 
of interest and depreciation. The actual unit cost for the whole 
job, however, would run very much higher than this, due to delays 
and repairs. 
