38 



BULLETIN 502, U. S. DEPARTMENT OF AGRICULTUEE. 



makes its fii-st turn, and running a little east of due north for about 

 200 feet. 



EXAMPLE VIII. 



The tract shown in figure 12 exemplifies the method of drainage as 

 applied where a broad, flat shale ridge contributed the seepage water. 

 Lateral A was installed two seasons prior to drilling the relief wells, 

 and no benefits whatever resulted from the drain. Both sides of the 

 trench were very wet almost to the surface of the ground wherever 

 the trench was opened for the purpose of connecting the relief wells 

 with the tile lines. After the wells were installed a marked improve- 

 ment became apparent almost immediately and the tract was put 



"X^^ ^^^\ "~ — ^^^^''"■^^=^=^7^ "'"'^ 



— 



■^— 



\, ^\ More than 6iee^ to Shale /\ .^ 















V ^"^-^ K^^^^^^^^^ 























'*^^^^^^^^^^^^^^^^^ 







^^^^^^p^/^^^^ 







^^^^^^^m. 







^^^^^^^ 



y^ 







(0 



^ 



V 



~yy 



\: 



■^ 



SCALE OF FEET •'^^ ^^^^^5^^ 







100 500 O' ^^^^^^^ 



ReJj'ef PVe//s. and Depth 23 o '-' 









•Sfrongesf F/oiv/nff (i^e/Zs _. • 







He/ffhf adoye Datum. 115 







Tile Drains.. ■^—'^ ~^ 













Fig. 12. — Forty-acre tract near Montrose, Colo., showing plan of drainage. 



under cultivation the following season with satisfactory results. 

 The depths of the most effective relief wells are indicated on the map. 

 Attention is called to the distances between wells, from 150 to 200 

 feet, which are unusually great. Generally speaking, this project 

 was one of water-logging rather than of alkali. The analysis of the 

 water discharged at the outlet of the tile system after completion is 

 represented by A in Table I. 



RESULTS OF DRAINAGE. 



Drainage of any type of agricultural land is successful only to the 

 extent that the land increases in productivity after the completion 

 of the drainage system. As illustrative that adequate drainage of 

 shale lands will fulfill this requirement, attention is called to Plates 



