124 



LAND DRAINAGE AND IRRIGATION 



combination it is usually better to make the surface-run at one 

 side of the tile after the tile is laid and when the land is dried 

 suflaciently to permit horses to work (Fig. 59). When completed, 

 the surface-run carries the water during flood flow, while the tile 

 works throughout the year. 



feet 



Cu/iivated 



Fig. 59.— Tile combined with surface-run. THe s:irface-run carries the water when there 

 is a flood, while the tile works throughout the year. (Wisconsin Station.) 



Tile Drainage is Profitable. — (Figs. 60 and 61.) It costs from 

 twenty to forty-five dollars an acre for complete tiling, but the 

 benefits to be derived far exceed the cost, as is shown by the four 

 typical examples in the following table: 



Cost <md Benefits of Tile Drainage 



Acres 



Conditions before drainage 



Cost of 

 drainage 



Conditions after drainage 



90 



16 



40 

 240 



A 60-acre field was poor 

 pasture, and a 30-acre 

 field was cultivated, but 

 most of the crops failed 



Was worthless for pasturing 



and cultivation 

 Grew willow brush 



Land was of little value for 

 pasture, and it produced 

 no hay 



$2,200 



$ 700 

 S1,000 

 $2,360 



Pasture improved 300 per 

 cent. The 30-acre field now 

 grows six times the amount 

 of grain as formerly, and no 

 failures 



Fine corn, clover and other 

 crops are now produced 



Now grows most excellent 



. corn 



Splendid crops of hay and 

 grain have been raised since 

 drainage. The value of one 

 crop offsets cost of tihng 



Vertical Drains. — Some vertical drains consist of openings or 

 cracks in underlying bed-rock, and cracks or openings made in 

 hard-pan ^ by the use of dynamite. It sometimes happens that a 



^A hard and impervious substratum is commonly called a hard-pan. 

 It may vary in thickness from a few inches to three feet and more. 



