258 



ENGINEERING ON THE FARM 



the furrow opens up the soil and carries the water to a depth 

 below the surface. This method with a large furrow is exten- 

 sively used in the irrigation of orchards, and with a small 



After Irrigation Investigations, U. S. Dept. Agri. 



Fig. 215. Furrow irrigation in orange orchard 



furrow in the irrigation of gardens and small fruits. Suffi- 

 cient water is turned into the furrow to keep up a continuous 

 current and to supply absorption, but not to such an extent 

 that there will be a current strong enough to start erosion. 

 Conveyors of water. While the open ditch is the common 

 method of carrying water to the point of distribution in sur- 

 face irrigation, it is not the only way. Conditions of the 

 land sometimes make it impracticable to use open supply 

 ditches, or the supply of water may not be great enough to 

 stand the seepage and evaporation losses and other methods 

 are employed. Canvas or other forms of hose are used, 

 particularly in the basin and check systems. Rectangular 

 wooden troughs or flumes (Fig. 216) have been employed 

 by gardeners for carrying water to the head of the furrow, 

 holes being bored in the sides to permit the water to escape 

 and then closed with wooden plugs or pieces of tin when 



