CANAL CONSTRUCTION. 



71 



stand the tearing force of freshets in the stream. Iron 

 gates came later and were fairly successful in with- 

 standing the attacks of storms, but they often caused 

 more serious damage to the lower bank of the fore bay 



.^ 





FIG. II — CANAL ON A HILLSIDE. 



and oftentimes led to its entire destrudlion. The gate 

 should be placed at a point convenient to discharge 

 water back to the river through the waste and sand 

 gates. The use of piling is necessary in soft ground, 

 although some builders continue to put in mudsills and 

 depend upon stone anchorage to keep the stru6lure in 

 place. The writer would advise wings to be put in on 



