IRRIGATION AND CULTIVATION. 



63 



flood-gates to dam up the water when required. Ordinarily 

 these flood-gates, except the one at b, are raised, and the water 

 flows along in its natural course unobstructed. But when 

 the soil begins to get dry, and shows the need of water, 

 the mountain brook is turned into the head ditch at b, and 

 the latter filled to overflowing. This alone will give the 

 whole strip next to the head ditch (i 1 1 1), a number of rods 

 in width, a pretty good soaking in a comparatively short 



Fig. 30. 



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Plan of Field Under Irrigation. 



time. Then by opening the flood-gates at the head of 

 the cross-ditches the water is turned into the latter, 

 allowed to rise to the top at the next set of flood-gates, 

 and by overflow and by soaking in, well distributed over 

 another strip parallel with the head ditch (2222). Then 

 these flood-gates are again raised, and the water allowed to 

 flow into the next section of the ditches, and so forth, 

 until the entire area has been well soaked. Just as soon as 

 the surface has again become dry enough for cultivation, 

 the ground should at once be stirred by means of the 

 wheel-hoe. 



The opportunities and soil conditions are not often so 



