570 ANNUAL EEPORT SMITHSONIAN INSTITUTION, 1916. 



however, was so urgent that funds were finally provided without con- 

 sidering the portage road favorably, and the canal work is now well 

 under way. The increase in the productive capacity of the rich ag- 

 ricultural lands of eastern Washington and Oregon and western 

 Idaho is fully meeting the early expectations, but it remains to be 

 seen how much the river will be used in the future as a line of com- 

 merce in competition with two parallel lines of railroad in the same 

 valley. 



At the mouth of the Columbia is a notable instance of river work, 

 which, for the boldness of its undertaking and the success attending 

 the work, has been widely studied and frequently commented on by 

 river engineers. The training of the river currents over the bar in 

 the ocean, including not only the tidal currents, but also those arising 

 from the natural discharge of the river, are so directed as to scour 

 greater depths, and the restriction of all useless side currents and the 

 shelter for the channel thus created are all accomplished by double 

 jetties of riprap so placed as to direct the dynamic effect of these 

 currents at a particular place on the bar. Originally bar depths 

 were from 19 to 21 feet, but already the controlling depth is 27 feet. 

 The south jetty is to be 7 miles long, extended into the open sea, 

 where storms are of great violence and often of long duration. The 

 north jetty is to be 2| miles long. The total sum expended has been 

 nearly $9,000,000, including the cost for maintenance. The south 

 jetty has been completed, and the north jetty has been started. A 

 depth of 40 feet over the bar is expected when the work is nearer 

 completion. 



The Sacramento is the principal river in California. The San 

 Joaquin River, which joins with the Sacramento at the head of 

 Suisun Bay, is used for navigation in the tidal portion up as far as 

 the Stockton Channel, about 45 miles, but above this point is not 

 exitensively used. The Sacramento is about 350 miles long, but the 

 uppermost 90 miles of the river is torrential in character and not 

 used for navigation. It is subject to numerous floods, which inundate 

 several hundred thousand acres in the center of the State nearly 

 every spring. Its low-water discharge is about 8,000 cubic feet per 

 second, and at high water it has reached 640,000 cubic feet per second. 

 Formerly the plan of channel development provided for securing 

 7-foot depth at low water up to Sacramento City, about 61 miles 

 from Suisun Bay. In this bay the depths up to the mouth of the 

 Sacramento are 14 feet and over. The project also provides for a 

 4-foot depth from Sacramento to Colusa, 90 miles, and 2 feet to 

 Red Bluff, about 110 miles farther. On this project over $740,000 

 has been spent, and the projected depths have been secured and 

 maintained for many years. The Sacramento River and the Feather, 

 a tributary, were very much subject, a few years ago, to deposits 



