90 HAUPT — THE MISSISSIPPI RIVER PROBLEM. | Feb. 19, 



lower down through the tributaries, where the confluence of waters 

 furtiier obstructs the flow and causes deposits, it is claimed that out- 

 lets would be harmful. But this is not the condition which would 

 prevail if properly constructed weirs and regulating works were 

 placed so as to permit the discharge of a portion of the excess of the 

 floods into suitably located impounding reservoirs, remote from the 

 erosive action of the river currents. It is also claimed that the 

 navigable channel would be injured by the reduction of volume 

 below the crevasses and that the bed would rise in consequence 

 thereof. This conclusion does not appear to be sustained either 

 in theory or practice. On this point Generals Humphreys and 

 Abbot state (page 387, Physics and Hydraulics^ , under the head of 

 ''Outlets " : " This plan consists in reducing the flood discharge 

 by waste -weirs and conveying the surplus water to the Gulf by chan- 

 nels other than that of the main river. The advantages of this sys- 

 tem have been stoutly contested by many writers, on the ground 

 that reducing the discharge of the Mississippi will occasion depos- 

 its in its channel, and eventually elevate rather than depress the 

 surface of the river." In support of this opinion they have urged 

 first that actual measurements upon the river at certain crevasses 

 prove that deposits are made when the velocity is thus checked, 

 and, second, that theoretical reasoning indicates that such deposits 

 ought to be anticipated. 



" Certain operations of this survey were conducted with especial 

 reference to determine the effects of outlets, and they demonstrate, 

 with a degree of certainty rarely to be attained in such investiga- 

 tions, that the opinions advanced by these writers are totally erro- 

 neous." 



The report then analyzes the two cases cited in proof of the asser- 

 tion, viz., the Fortier crevasse of April, 1849, ^^^ t^"^^^ ^^ Bonnet- 

 Carre of 1850, and shows that the phenomena attributed to the 

 breaches were those ordinarily found to result from bends and 

 straight reaches, and that in fact even in a natural crevasse there 

 was no bar formed below such opening in the banks, and that '' the 

 assertions to the contrary are erroneous." They add : '' There is 

 no evidence whatever that any filling up of the bed ever did occur 

 in consequence of a high-water outlet, and, moreover, it is impos- 

 sible that it ever should occur, either from the deposition of sedi- 

 ment held in suspension or drifting along the bottom. The conclu- 

 sion is then inevitable that, so far as the river itself is concerned^ 



