UNITED STATES DEPARTMENT OF AGRICULTURE 
Contribution from the Bureau of Public Roads 
THOS. H. MacDONALD, Chief 
Issued Nov. 10, 1915 
PROFESSIONAL PAPER Revised Aug. 22, 1922 
Washington, D. C. 
EXCAVATING MACHINERY USED IN LAND 
DRAINAGE. 
By D. L. YARNELL, Senior Drainage Engineer. 
CONTENTS. 
Page. Page. 
Introduction —__-_________________ The drag-line scraper excavator____ 29 
Development of cxcavating ma- The dry-land dipper dredge __-_____ 44 
ehinery —===———- ——_________ The dry-land grab-bucket excavator_ 47 
Comparison of kinds of power_----- 2 | The wheel excavator ______________ 48 
Determination and analysis of cost The hydraulic dredge ____________- 50 
data ~_--___-~----~--~~--------- 9 | Machines for cleaning old ditches___ 58 
The floating dipper dredge____---_- SUED Surana Tey; oe ee ee ay 59 
The floating grab-bucket dredge____-_ 28 
INTRODUCTION. 
The use of power machinery for the construction of drainage 
ditches and levees has become general in this country. Not only 
have new types of excavators been put on the market in recent years, 
but the older ones are being constantly improved to meet the re- 
quirements of drainage work. It is essential that the drainage en- 
gineer, upon whom rests largely the responsibility for the proper 
planning and execution of drainage undertakings, keep himself in- 
formed not only of the improvements constantly being made in ex- 
cavating machinery but also as to the special advantages and limi- 
tations of the various types of machines. Contractors usually are 
required, when submitting bids, to describe in a general way the 
machinery they intend to employ. Only by being familiar with 
such machinery will the engineer be able to decide as to its suita- 
bility for his project or to estimate intelligently the cost of the work. 
DEVELOPMENT OF EXCAVATING MACHINERY. 
Open drains were no doubt dug on wet agricultural lands during 
the early settlement of this country. Since only hand tools were 
then in use, the ditches were small. If the channel was too large 
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