UNITED STATES DEPARTMENT OF AGRICULTURE 
BULLETIN No. 300 
Contribution from the Bureau of Public Roads 
THOS. H. MacDONALD, Chief 
Washington, D. C, PROFESSIONAL PAPER Revieed Aug. 22, 1922 
EXCAVATING MACHINERY USED IN 
LAND DRAINAGE 
By 
D. L. YARNELL 
Senior Drainage Engineer 
CONTENTS 
Introduction The Drag-Line Scraper Excavator. . . 
Development of Excavating Machinery. The Dry-Land Dipper Dredge 
Comparison of Kinds of Power .... 2 | TheDry-Land Grab-Bucket Excavator . 
Determination and Analysis of Cost The Wheel Excavator 
The Hydraulic Dredge 
The Floating Dipper Dredge Machines for Cleaning Old Ditches. . 
The Floating Grab-Bucket Dredge . . 
WASHINGTON 
GOVERNMENT PRINTING OFFICE 
1922 
