PROTECTIVE WORKS. 



619 



apart, are dug all over the area, being arranged like the 

 wattle-fences in Fig. 281 ; their construction on very steep 

 slopes is evidently not unattended with danger. 



.& 



Fig. 281. Plan of fences for protection against avalanches. 

 a I. Line where the avalanches commence, c. Fences. 



(I)} Rows of Wattle-Fences. The stakes used may be either 

 of wood or iron. These are set up at intervals of from 20 to 

 50 feet, their central points being at those of a series of 



Fig. 282. Dry masonry wall for protection against avalanches. 



equilateral triangles ; they should be 15 to 30 feet long, and 

 of wattle-work with branches plaited between stakes firmly 

 driven into the ground. 



Such a system of wattle-fences allows soil to be formed on a. 



