38 BULLETIN 502, U. S. DEPARTMENT OF AGRICULTURE. 
makes its first 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 
SCALE OF FEET 
0 
relief Wells,and Depth.......... 23° 
Strongest Flowing Wel/s...------- ® 
Helght above Datum...-..-. ——|15—— 
GUL CORD ILTS Ps Ne jare ee Ie _—_—_— 
W.D.N. 
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 
