576 ANNUAL EEPORT SMITHSONIAN" INSTITUTION, 1916. 



to the Gulf with only a small fraction of its former traffic. A marked 

 diminution in appropriations for all rivers in this valley may be 

 expected in the next few years. Already signs are pointing to a 

 more careful scrutiny of all work proposed in this region and to 

 a closer study into the probable benefit to the country as a whole 

 of the large expenditures now being made annually. 



Third, it is gratifying to note the healthy growth in the commerce 

 of many of those coastal rivers which flow into seaports and enable 

 deep-draft vessels to reach interior cities from the sea. Coal is an 

 important item of their cargoes, and the lowering of the cost of 

 this commodity is widespread in benefit. This character of channel 

 development may be expected to continue to increase in capacity as 

 long as an increase in traffic and saving in cost of transportation can 

 be shown. Here, too, it seems probable that new work will more than 

 ever need to have conclusive reasons given for its adoption by the 

 Government before it can be undertaken. 



Fourth, the success in the application of the lessons learned by 

 experience in the jetty system of deepening the entrances to rivers 

 from the sea has been very satisfactory. The Columbia River, the 

 Mississippi River, and the St. Johns River are all examples of diffi- 

 cult kinds of engineering in which Americans have been pioneers, 

 and the results are exceptionally satisfactory. Nowhere in the world 

 have such daring attempts been made, and nowhere have results been 

 more effective. The great perfection of the suction dredge has so 

 reduced the cost of channel excavation that now new channels are^ 

 being deepened that before were too expensive and hazardous for 

 even a conclusive trial, as in the case of the Ambrose Channel en- 

 trance to New York Harbor. This method of deepening, so useful 

 in interior channels, has also been widely adopted as an auxiliary 

 to jetty work, and is now generally recognized as a necessary aid in 

 bar improvement. Although dredging in some harbors, as at the 

 mouth of the Columbia, has not demonstrated its value in this place, 

 still the results at Galveston, Mississippi River, St. Johns River, and 

 New York, and nearly all ports on the Atlantic and Gulf coasts, have 

 been conclusive. 



Fifth, the recent, but nevertheless desirable, combination of sev- 

 eral governmental activities in river work under a single head has 

 been again recognized in the Sacramento River. For some years 

 the control of floods on the Mississippi by levees has been carried 

 on by a cooperation of the State and Federal forces, under a tacit 

 agreement never specifically stated in the law. On the Sacramento 

 we now find reclamation of flooded areas, control of floods, deepen- 

 ing of channels for navigation, and the exclusion of mining debris 

 all included under the Federal management by law. In this work 

 the State assists by paying one-half of the expense, by donating the 



