HYDROLOGY OF NEW YORK 



779 



view of the fact that the increase of detention at high locks only 

 increases the detention for additional- time required to fill the lock 

 chamber, it was concluded that the advantages to be derived from* 

 quick time and from developing shipbuilding industries was of 

 more importance than a small decrease in traffic capacity. 



The dimensions of lock structures which will best subserve the 

 foregoing conditions were investigated with the following results : 



Single locks for a 30-foot waterway are to be 740 feet long and 

 80 feet wide and to have lifts conforming to the present develop- 

 ment of waterpower on the routes. That is, the hight of lift 

 will be whatever the present power dams are. 



For a 21-foot waterway the locks are to be 600 feet long, 60 feet 

 wide and with the same hight of lift as in the foregoing. At 

 Lewiston, Long Sault rapids on the St Lawrence river and at 

 Champlain, the natural conditions require lifts of from 40 to 50 

 feet. 



Dams and sluices. Dams on the Mohawk and Hudson rivers 

 were designed with as great a length as the natural conditions 

 would permit in order to keep the range between stages of high 

 and low water as little as possible. This range can be further 

 reduced by making the crests movable. Sluice gates of the Stoney 

 type are provided where long dams are not desirable. With four 

 exceptions the dams can be constructed on rock foundations, and 

 at the locations where rock is not available the heads on the dams 

 will be small. 



Breakwaters. At Olcott. and Oswego, terminals of the Niagara 

 ship canal and of the Oswego-Mohawk route, artificial harbors 

 protected by breakwaters will be necessary. A study was made 

 of the type best adapted to the conditions at these harbors and 

 the results are given. 



Cornell experiments. Uncertainty as to the value of the coeffi- 

 cients in the ordinary weir formula rendered it desirable that 

 additional investigations should be made before estimates could 

 be made either of the value of waterpower rights or of the 

 amount of slope wall and bank protection to be used between the 

 limits of high water and low water stages of the proposed water- 

 way. Previous to the Cornell investigations there was very 

 little certain information as to the flow over weirs when the depth 



