376 



IRRIGATION PRACTICE 



gator to reduce this area by wiser methods of conducting 

 and using water. 



226. Lined ditches a remedy. The chief danger of 

 seepage will remain with the canals and laterals, for it is 



FIG. 106. Chain puddler. Used in making canals watertight. 



relatively easy to control the quantity of water used on 

 the land. The first obvious remedy against seepage is, 

 therefore, to make the ditches more impervious. A canal 

 carrying clear water will not of itself become impervious, 

 but a canal carrying muddy water will receive the settlings, 

 often to such a degree as to reduce or even to stop the 

 seepage. Moreover, the leaks due to layers of gravel, sand 

 or open rock, over which canals pass, should be stopped 

 by the application of clay or some other impervious 

 material. Very often, it is advisable to line the whole 

 canal with impervious materials or to build flumes or 

 pipes to take the place of the canal. The first expense 

 seems large, but the annual saving of water and the 



