ENCLOSING DAMS. 67 



The outer row of piles projected 8 feet above ordinary high 

 water, as at times the height of this ordinary tide level was 

 much exceeded. The inner gauge-piles came up to the same 

 level, but the row of sheet-piling was only carried up to the 

 level of ordinary high water. 



The walings were arranged as shown by Fig. 49. The 

 lower waling or the inside consisted of laminated timbers break- 

 ing joint. 



This dam would have been more efficient had the inner piles 



-ET 



Datum 



2.0, 



Highest Flood Level 



Ordinary Water Level 



Ordinary Low Water 



SCALE. 



5 ip IB FEET 



FIG 49. 



been of whole timbers carried up to the same height as the 

 outer row, and if the upper inside waling had been made of the 

 same strength as the lower laminated walings. The timber for 

 the piles, however, were required of exceptional length, and so 

 many were needed that it became a difficult matter to procure 

 a sufficient number of the right size ; hence it was an object 

 with the contractors to adopt a design which would allow of 

 shorter timbers being used. 



In order to construct the dam, a dolphin was first erected 



