558 



ANNUAL EEPOET SMITHSONIAN INSTITUTION, 1916. 



stages rise, sections of the dam are dropped until at high water no 

 special obstruction to the flow of the river is offered, and navigation 

 can proceed over the dam, without difficult3\ This project was 

 planned to be finished in 12 years. No records of the total commerce 

 of this stream have been compiled during recent years, but at the 

 various locks statistics of traffic are kept. The records at the Louis- 

 ville lock of the commerce passing this point have been maintained 

 for many years. It is shown in the following table for five-year in- 

 tervals, to indicate present tendencies : 



Tons. 



1910 1, 041, 323 



1913 1, 446, 787 



Tons. 



1895 1, 129, 644 



1900 1, 574, 194 



1905 1, 242, 250 



The tributaries of the Ohio comprise an extended sj^stem of navi- 

 gation which reaches a large part of the Mississippi River basin. 

 Along these tributaries, most of which enter the Ohio from the 

 south, are over 4,000 miles of navigable channels. Many of these 

 tributary rivers are under improvement of a most modern and effi- 

 cient type, and new projects of great interest have been begun on 

 several within the last decade. The Kanawha River was the first 

 to be equipped with navigable dams. The project for this work was 

 adopted in 1875, but it was not until 1897 that the work was com- 

 pleted. The total cost was $4,158,000. This covered the construction 

 of eight movable dams and two fixed dams, a system which has 

 given a 6-foot depth throughout the length of the canalized portion 

 of the river, of about 90 miles. Until the completion of railroads 

 along the banks of this stream, the commerce consisting principally 

 of coal, was of considerable size, with every indication of a marked 

 increase in the future. This stream, like so many others in the Mis- 

 sissippi basin, is not maintaining its importance as a freight carrier 

 since the completion of the principal railroads, as will be shown by 

 the following table. Nothwithstanding a great increase in the pro- 

 duction of coal in the region of this river, the commerce of this 

 stream has not expanded: 



Ton3. 



1905 1, 613, 889 



1910 1, 122, 102 



1912 1, 276, 540 



Tons. 



1885 1, 231, 882 



1890 1, 127, 232 



1895 1, 082, 342 



1900 1,475,930 J 



The cost of maintenance during 1912 was $97,002.78. The movable 

 dams on this river are of the Chanoine wicket type and have proven 

 eminently successful in providing pools for 6- foot navigation. As 

 an engineering problem alone, the solution has been very satisfactory. 



The most important tributary of the Ohio, in point of traffic, is 

 the Monongahela. On this stream are located many coal mines, par- 



