RESERVOIRS AND PONDS. 



73 



ized in this form of dam by the weight of water which 

 lies upon the sheeting. 



The tiers of timber are built up, saddled and 

 notched. A plank sheeting is put down to the solid 

 foundation above the first sill, and the end is spiked with 

 eightpenny spikes firmly. The sheeting is filled to the 

 foundation as close as possible, and hydraulic cement 

 concrete is bedded in front of it to make a tight joint. 



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FIG. 19. A DIVERTING DAJI. 



No leaks will ever trouble a dam founded in this way. 

 The rafters should be strong enough to bear any weight 

 of water which the stream may carry doubled. If the 

 highest flood known is five or ten feet above the usual 

 level, it is easy to estimate the strength of the rafters 

 required and then double the number of them, putting 

 them no more than two feet apart, if the sheeting is of 



