790 



NEW YORK STATE MUSEUM 



thereto at this time. So far as the United States is concerned, 

 experience on the Erie canal in New York State is the most ex- 

 tensive of any. 1 



From the foregoing data of annual traffic and tonnage per lock- 

 age we have a total lockage per year of 8333, and adding the usual 

 50 per cent for two ends of summit level, 4167, we have a total 

 number of lockfuls of water of 12,500. 



Assuming 222 days of navigation, we have the following: 

 Volume of one lockful =(740 x 80 x 20)= 1,181,000 cubic feet. 



For mean water supply per second, we have : 



12,500 x 1,184,000 

 222x24x3,600 = 772 CoWc 



or, for even figures, we may place the lockage requirement at 

 800 cubic feet per second. The foregoing quantity of 800 cubic 

 feet per second expenditure of water for lockage is based upon 

 absolutely uniform distribution of vessels, both as to direction 

 and season. As a modifying *f actor we should take into account 

 these elements : 



1) Since the feeder has no storage in the vicinity of the main 

 canal a draft in excess of the mean quantity must be drawn from 

 the main channel itself. 



2) There will be a tendency to more lockage in daylight than 

 at night. 



3) In the spring of the year, on account of the preponderance 

 of the grain trade, the larger proportion of movement will prob- 

 ably be, for a time, from west to east. At other seasons there 

 are likely to be times when the traffic will be in excess in one 

 direction. The estimate of one and one half lockfuls of water 

 for each vessel passing the summit is based on uniform distri- 

 bution of the traffic, otherwise two lockfuls per vessel passing 

 is required. The proper addition to the lockage requirement on 

 account of such irregularity can not be definitely determined 

 until one has statistics of the actual movement covering a series 

 of years. In the absence of such the foregoing may be pointed 

 out as a reason why the lockage requirement should be properly 

 placed somewhat larger than the theoretical figure. 



'For these data reference may be made to the section on Loss of Water 

 from Artificial Channels in this report There are a number of other refer- 

 ences, ns Water Supply of Western Division of Erie Canal, etc. The Barge 

 Oanal Report contains a resume of the preceding, together with the Euro- 

 pean data, etc. 



