94 HAUPT — THE MISSISSIPPI RIVER PROBLEM. [Feb. 19, 



to commend them to the consideration not only of engineers but of 

 economists, business men, farmers and real estate dealers ; and that, 

 so far as the evidence of nature goes, their operation is only bene- 

 ficial and in no wise injurious. If they were closed and the river 

 leveed, all of the advantages named would be destroyed and the 

 sediment would be carried to the mouth, where it would extend the 

 bars more rapidly, raise the flood plain and require elevation of the 

 entire system of levees along the river banks. 



But there is another class of outlets which may be considered in 

 this connection, and that is the bars which obstruct the mouths and 

 thus prevent the free discharge of the fluvial waters. These may be 

 distinguished as longiiudinal outlets, and their permanent removal 

 is entirely practicable by applying the energy of the river to the 

 work to be done. 



It is a well known fact that a sedimentary stream, flowing through 

 a straight reach, seldom maintains a single permanent channel, 

 while in swinging around curves the concave bank, acting as the 

 directrix, causes a reaction which deepens the bed and deposits the 

 silt upon the complementary convex bank which is the resultant of 

 this action. 



In this way, by the operation of natural laws, the deposits are 

 removed from the path of navigation and the cross-section is auto- 

 matically adjusted to the requirements of the river. Instead, there- 

 fore, of building two parallel jetties as substitutes for the natural 

 banks, and thus extending the river into the Gulf at the expense of 

 its slope and the reduction of its area of discharge along straight 

 lines, which are unnatural and unfavorable, it will be found more 

 rational to build one curved training wall so placed as to create a 

 head and reaction which will transport the silt to the opposite or 

 convex bank, where it will be deposited without cost, leaving an 

 ample navigable channel and saving the expense of one of the 

 jetties, while it also scours away the bar directly in front of the 

 mouth and affords an open passage for the effluent water. 



By thus utilizing the tendency of water to flow in curved lines 

 instead of straight ones half the cost of the jetty works may be saved 

 and a better and more permanent channel be obtained, with a low- 

 ering of the flood heights of the river. This result is due to the 

 form of the orifice, and it will be seen that when no such modifica- 

 tion is applied the effluent stream is abruptly checked by the 

 inertia of the Gulf water and the sediment thus deposited acts as a 



