28 PHYSICAL GEOGRAPHY OF 



The volume of water which the river actually furnished in each month (with 

 those two exceptions) was sufficient to have maintained a depth of 5^ feet on 

 the Wheeling bar, without reserving the excess of any previous month. All 

 that was needed to obtain and secure a minimum depth of 5| feet for naviga- 

 tion, was to regulate the actual discharge of each month. 



In September the water was down below two feet on the bar ; yet the dis- 

 charge for that month alone would have maintained a navigation for boats of 2 

 feet 9 inches draught. 



In October the water was twice down to 2 feet 2 inches, and several times 

 below 2^ feet; yet the supply for that month, without any reserve for previous 

 excess, would have maintained a uniform draught of 3 feet 5 inches. 



The total discharge for September was - - 10,587,000,000 cubic feet. 



The total discharge for October - - - - 15,173,000,000 « " 



The total actual discharge for September and 



October, together, amounted to - _ . 25,760,000,000 " " 



To have maintained a navigation during these two months for boats drawing 

 5 feet would have required a daily supply, according to Table IV, of 864,000,000 

 cubic feet; or a total, for the whole period of 61 days, of 52,704,000,000 cubic 

 feet. 



The difference between this — the quantity which would be discharged with 

 five feet on the bar— and the quantity which was actually discharged, is then 

 26,944,000,000 cubic feet. 



This is the volume of water which it would have been necessary to provide 

 that year to have kept the river at a minimum height of 5 feet. 



The volume here deduced from actual measurement on an extensive scale, 

 would very nearly fill a reservoir 107 feet deep, and covering an area of three 

 miles square. 



It would require only three dams, no larger than several of those in use on 

 the Lehigh, to be constructed across the Alleghany, to supply the whole of this 

 volume of water. Three such dams can be built in the usual manner, and fur- 

 nished with locks for the accommodation of the trade above, as is common on 

 other great rivers, and be completely provided with the means of drawing off the 

 water, as it is needed, for about ^450,000. 



