1S 
UNITED STATES DEPARTMENT OF AGRICULTURE 
BULLETIN No. 502 | 
Contribution from Office of Public Roadsand Rural Engineering 
LOGAN WALLER PAGE, Director 
= 0% x 
Washington, D. C. PROFESSIONAL PAPER April 23, 1917 
THE DRAINAGE OF IRRIGATED SHALE LAND.’ 
By Datton G. MittErR, Senior Drainage Engineer, and L. T. Jessup, Junior 
Drainage Engineer. 
CONTENTS. 
Page Page 
Pr GROMUGEIOM eee eens ak ae eae Een eee | 1 i COnstrichlonetee nasser eee epee see 20 
Geolosicalifeatnes aes q05 52s eee aes ae 7A a OL0'S) FCG EN eee PS ON a A SS NS re a 22 
Suna cerionpornrapltyes = sees. = sane ee ee nee es 3) Exam plesiommethods Se. aa2 sas" see ee eee De 
Underoround wateros2 tess 22 teehee 4 Resultsiohdramea restos shee eee 38 
PUGH ESE BS SSE See es ane ater il re nee a ag if | Conclusions. aoc aqecae vase eae eee cee tae 39 
MramacamMennods eta eee eee ft | 
INTRODUCTION. 
Drainage is now recognized as one of the most important problems 
confronting the farmers of irrigated lands. Drainage methods in 
the arid regions differ from those in the humid sections, and even 
with respect to arid land different methods must be used for different 
types of land. One of the frequently occurring types that require 
special treatment is the so-called shale land, by which term is meant 
those lands that are immediately underlain by shale which may or 
may not outcrop and in which the soil is made up largely of dis- 
integrated shale. Areas of this type occur in all of the Rocky 
Mountain States and in some of those immediately adjoining. 
In spite of the fact that shale is classed among the less pervious 
formations, it becomes an important factor in the movement of under- 
ground water in those areas where uplifts and displacements have 
occurred. Investigations by this department have shown that in 
those sections which have underlying shale near the surface there is a 
close relation between the shale and the areas of seepage. This rela- 
tion depends more or less on the topography of the underlying shale, 
iThis bulletin contains information on the drainage of those irrigated lands of the 
Rocky Mountain States that are underlain by shale. 
ACKNOWLEDGMENTS.—The soil analyses presented in this bulletin were made in the 
laboratory of the Bureau of Soils, U. S. Department of Agriculture. The analyses of 
the water samples were made in the water laboratory of the Bureau of Chemistry, 
U. S. Department of Agriculture. 
70250°—Bull. 502—17 ul 
