122 IRRIGATION. 



process of doubling or trebling the usual amount of the 

 crop. 



The first business to be undertaken in forming such a 

 meadow is to thoroughly drain the land either by under- 

 drains or by open drains. The most important drain will 

 be that which cuts off all the springs which issue from 

 the foot of the uplands, and which generally render the 

 low land a sodden marsh. Frequently this drain should 

 be dug to the depth of six feet, that every spring that 

 may issue below may be intercepted and tapped. This 

 drain should be cut above the highest level to which the 

 irrigating ditch can be carried, and may discharge into it 

 or be carried beneath it and made to issue in the lateral 

 drains. Next, the surface is to be leveled, the hillocks 

 cut down and the hollows filled, so that no stagnant wa- 

 ter can be retained in them, and the lateral slope of the 

 meadow be made perfect up to the edge of the stream. 

 The stream, or so much of it as can be used, is then di- 

 verted into side channels, which are carried as nearly upon 

 a level as possible until they reach the foot of the upland, 

 when they are carried still upon a level or with a slope of 

 not more than one foot in a thousand, in a direction paral- 

 lel with the general course of the valley, but yet follow- 

 ing the winding made necessary by the configuration of 

 the surface. The general arrangement of the dam, canals, 

 and drains, is as follows : see fig. 55. The winding stream 

 which occupies the center of the valley, shown by the 

 dotted lines is straightened, and dammed at a ; the lat- 

 eral canals are carried each way from the dam to the 

 borders of the valley, and from them a regular system of 

 distributing canals is supplied. The main eross drains, 

 J, l t are above the canals on either side, and the drains, 

 shown by the dotted lines, are carried directly to thQ 

 stream, or they may be made to discharge into the water 

 furrows if so desired. The level of the stream may be 

 raised by embanking its sides for a sufficient distance, in- 



