574 ANNUAL EEPORT SMITHSONIAN INSTITUTION, 1916. 



and on former work. In 1910, the project was further amplified 

 to provide a depth of 35 feet, and a channel 800 feet wide in the 

 straight parts and 1,000 feet wide at the bends, all at an estimated 

 cost of $10,920,000. This work involves the removal of 53,000 cubic 

 yards of rock and over 73,000,000 cubic yards of soft dredging. 

 Two suction dredges are now constantly at work on the new project. 

 About $2,000,000 has been spent thus far, and the new work about 

 one-eighth completed. In recent years the commerce has shown a 

 healthy increase. 



In 1890 it was 11,356,270 tons. 

 1895 it was 18,626,853 tons. 

 1900 it was 21,910,232 tons. 



1905 it was 24,383,571 tons, valued at $1,612,847,499. 

 1910 it was 24,677,671 tons, valued at $1,327,869,862. 

 1912 it was 26,267,335 tons, valued at $1,235,106,621. 



By far the largest item of this commerce is coal. It will be seen 

 from these figures how important a part in the development of this 

 enormous traffic the channel development has played. 



The St. Johns Kiver, in Florida, is another example of increasing 

 traffic, fostered and encouraged by well-chosen river work. This 

 stream was originally closed at its mouth by a bar on the ocean, 

 over which there was only 5 to 7 feet depth at low water. By means 

 of two jetties, supplemented by dredging, these depths have now 

 been permanently increased to 25 feet at low w^ter. The upper 

 river, also, was originally interrupted by shoals of about 11 feet 

 depth. In 1879, a project was adopted for a channel having a depth 

 of 15 feet from Jacksonville to the sea, 27.5 miles. In 1892, it was 

 found that the channel over the bar had been fixed in position by 

 jetties, and the depth increased, by that time, to 13 feet at lew 

 water, and a new project for 18 feet depth of channel was thereupon 

 adopted before the earlier work had been completed. This latter 

 project was completed in 1894. In 1896 the proposed depth of 24 

 feet at low water and width of 300 feet was approved, and work 

 was undertaken. This project was practically completed in 1910, 

 when the present project of a 30-foot depth of channel was adopted. 

 The newly proposed width is 300 feet in straight reaches and 600 

 feet at bends. On the earlier projects $4,000,000 has been expended, 

 and on the present plan $1,266,912, and work is about half com- 

 pleted. This new channel has been very effective in affording 

 cheaper lines for freight destined for northern ports and affects a 

 large and prosperous area. Commerce has increased at a healthy 

 rate and has justified the original estimates of growth, and appar- 

 ently warranted the expenditures necessary. 



