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 4^ feet deep. Immediately hi 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 1^ 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 hi 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. 



