THE MISSISSIPPI VALLEY, 31 



months, to 4 feet — could be built upon those rivers for an outlay of not more 

 than ^150,000 each. 



In 1847 the depth was sometimes as low as 2| feet at Wheeling; yet it will 

 be seen, by reference to the table for that year, that in each month the natural 

 flow was sufficient, if it had been M'ell regulated, to have maintained an uniform 

 depth of at least four feet throughout the month. 



In the month of July (1847) the depth on the Wheeling bar was frequently 

 but 3 feet, and once less than 3 feet; yet, the discharge for that very month was 

 sufficient to have maintained an uniform depth of 5^ feet. 



In August the depth was also reduced below 3 feet ; but the average flow 

 was sufficient to have maintained it throughout the month at 4i feet. 



In September the water fell to 2^ feet, and varied from that to 4 and 5 feet. 

 The actual flow, as shown by the table — the results of which are obtained in all 

 cases from actual calculation for each day — would have maintained the height 

 constantly, the whole month, at 4 feet. 



Now, all that was needed to protect the navigation throughout 1847 was 

 two small dams — one on each of the great branches of the Ohio — to create 

 reservoirs of moderate capacity, to be vented as the river fell on the occurrence 

 of a drought ; and to catch the surplus water furnished by the small freshets 

 which occurred during the summer, and discharge it again, as needed, into the 

 stream below. 



To supply a large volume of water, with a view to the maintenance of a depth 

 sufficient for the proper movement of the largest class of freighted boats, would 

 require capacious reservoirs, and an outlay of some six or, possibly, seven hun- 

 dred thousand dollars. But merely to regulate the actual summer discharge, 

 so as to make it uniform, and supply the additional quantity which would be 

 needed to keep a depth of only four feet on the bar at Wheeling throughout 

 the year, would involve an outlay little, if any, greater than the cost of two of 

 the locks and dams in actual use on the Monongahela navigation. 



