344 Irrigation and Drainage 



described above ; then, when the water is to be carried 

 forward, the dams are also shifted. 



As represented in the figure, water may be carried 

 directly down the slope across a series of secondary 

 furrows, as at C, D, D, D, and the main supply fur- 

 rows may be set one below another at such intervals 

 as the extent of the fields and the slope of the 

 surface may demand. In the figure, a second water 

 furrow is marked "supply and drain ditch," but if 

 the best work is done in handling the water, there 

 should be no surplus to drain away. 



When slopes like those under consideration are 

 in permanent meadows or pastures, or if they are in 

 meadows for three or more years, it will be best 

 usually to give more time to shaping the furrows, 

 so that washing will not occur when less attention 

 is given, and so that the mower and horse rake may 

 readily work over and across them. 



In European countries, where so much labor is 

 done by hand, little attention has been paid to 

 developing systems of applying water to fields which 

 will readily permit of the use of machinery, as must 

 be the case in this country, at least for a long time 

 to come. 



Where grain fields are not very long, and where 

 the slope is gentle and uniform, the water may be 

 distributed from a single head ditch by simply mark- 

 ing the field, after it has been sowed, with a tool 

 like the corn -marker, but having runners close enough 

 to give shallow furrows every 15 or 20 inches. 

 These shallow furrows lead the water forward in par- 



