President's Address. 65 



impede the current. Almost invariably the openings through them 

 are so few and so entirely inadequate that they cause the water in 

 the river valley to rise much higher than it otherwise would, and 

 therefore such grades become one of the great flood producers. 



CHANNEL STRAIGHTENING. 



Advocates of channel straightening have many points of fact 

 with them. The fundamental principle underlying this method is 

 the hurrying away of water already in a channel so that it may not 

 be present when the last of the flood- waters arrive. Anything what- 

 ever which impedes the water current in a stream tends to produce a 

 flood. In its qualitative influence it becomes a flood producer, be- 

 cause it holds back water already in the channel until new rainfall 

 water may overtake it. Conversely, any influence which will hurry 

 water along and get it out of the way tends to prevent a flood, and 

 therefore should be applied wherever feasible. The universal ten- 

 dency of streams with flood-plains is to silt up their channels, as 

 already pointed out. This filling in process is greyly increased by 

 driftwood, stumps and other objects becoming lodged, which retard 

 the velocity of the water in the bottom of the stream. Clearing a 

 river channel of stumps and trees and snags, therefore, in a measure 

 increases the velocity of the water. One can hardly believe that 

 intelligent landowners would spend vast sums of money in river 

 improvements to prevent floods and at the same time neglect to 

 provide against such river obstructions. But we find these con- 

 tradictory actions in many parts of America. 



Suppose a drop of rain falling at Junction City occupies four 

 days in traveling to Kansas City, and suppose again that by re- 

 moving impediments in its pathway its velocity could be increased 

 so that it would make its journey in three days. Certainly at any 

 given point throughout its course it would be out of the way much 

 earlier than should no improvements be made, and, therefore, its in- 

 fluence as a flood producer would be correspondingly lessened. If 

 now we find a stream which has carried its meanderings to such an 

 extent that the length of its course has been doubled, the length of 

 time required for water to travel the course likewise would be 

 doubled, yes, more than doubled, because its actual velocity would 

 be in a measure retarded. Throughout the course of every stream 

 with a flood-plain meandering is more pronounced in some places 

 than in others, and in such places a maximum good could be ac- 

 complished by straightening the channel. 



In the southeast corner of Bates county, Missouri, the Marais 

 des Cygnes river has excessive windings throughout a stretch of 

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