280 MISCELLANEOUS FARM SUBJECTS 



wells; pumping from wells, lakes, or streams, and storage of storm 

 water from surface flow or from drainage systems. 



Diversion from Streams. Diversion from perennial streams is 

 the most common method of securing irrigation water, and it is 

 available for either great or small undertakings wherever unappro- 

 priated water flows in sufficient amount. 



After assuring himself that a near-by stream carries sufficient 

 water for his purpose, the next step for the farmer is to determine 

 whether the water can be brought to his land at a reasonable ex- 

 pense. This will depend principally upon the length of the ditch 

 which must be constructed. The simplest way to find out how long 

 the ditch must 'be is to run a line having the necessary grade from 

 the highest point of the land to be irrigated upstream till it strikes 

 the stream. The grade on which the ditch should be built, and con- 

 sequently upon which this preliminary line should be run, will de- 

 pend upon the quantity of water to be carried and the nature of the 

 soil over which the ditch will run. In general, the larger the ditch 

 and the lighter the soil the smaller the fall which can be given to 

 the ditch ; and the shorter the ditch the smaller the fall. However, 

 the grade should not be too light, for the ditch may have to be made 

 larger to carry the desired supply of water. On the other hand, the 

 grade can not be very heavy or the strong current will wear away 

 the diteh banks. Therefore the range of the grades which may be 

 given to a ditch is limited. In ordinary soils a grade of 2 inches in 

 100 feet may be given to small ditches, and in clay soils as much as 

 3 to 5 inches in 100 feet may be given. 



Should the line run in this way be too long, the stream below 

 the point where the line strikes it should be examined to see if there 

 is any place where the water can 'be raised by a dam high enough 

 to flow into the proposed ditch. In case no such place is found, a 

 water supply from that source must be abandoned. 



Building the Ditch. Having decided upon the point of di- 

 version and located the ditch line, the farmer is ready to build the 

 ditch. The line of the ditch should first be marked by a furrow. To 

 do this, let one man guide the team, walking between the heads 

 of the horses, holding a bit in each hand while another holds the 

 plow. The furrow should be turned to the lower side of the ditch. 

 If the surface of the ground is comparatively level across the line 

 of the ditch, it is not necessary to follow the stakes closely in the 

 bends. The ditch will be better for being straightened a little, 

 which may be done by going above the stakes that locate the bends 

 nearest the stream and below the stakes farthest away. If the 

 ground slopes very much across the ditch line the stakes must be 

 followed closely. After the line is marked, two or three furrows 

 are plowed, all being turned to the lower side. A farm ditch can 

 be made almost wholly with an ordinary plow by going over the 

 line a number of times. The loose earth in the bottom of the ditch 

 may be removed with a scraper or shovels. 



A small stream can be easily diverted into a ditch, if it is run- 

 ning in a shallow bed, by a cross-stream dam of posts and plank, of 



