60 Kansas Academy of Science. 



of man will be powerless in the prevention of great disaster. Such 

 an agent of destruction should be looked upon in a measure as we 

 look upon earthquakes and tornadoes and volcanoes — nature's great 

 processes for modifying and beautifying the surface of the earth — 

 and man should avoid their disastrous results principally by keep- 

 ing out of their way. It should not be considered a mark of the 

 highest degree of intelligence deliberately to put one's self direc'ly 

 in the pathway of such a manifestation of nature's forces. 



The above general statements refer to major or excessive floods. 

 A great many minor floods occur which are less destructive in their 

 action, and which, in a measure, certainly may be modified and 

 made less severe. Three different lines of improvements or methods 

 have been suggested, commonly called the reservoir method, the 

 levee method, and the channel-straightening. method. These may 

 be considered separately. 



RESERVOIRS. 



Flood prevention by the reservoir method is believed in by those 

 who consider it feasible to build many reservoirs throughout the 

 drainage area of a stream so that a portion of the rainfall water may 

 be caught in the reservoir and doled out leisurely to the streams 

 under the control of man. It is argued that it is the last portions 

 of the rainfall added to rivers which cause the floods, and that 

 therefore such portions as may be held in the reservoirs will in a 

 degree keep the "last portions" from entering the stream and 

 thereby prevent the flood. But the facts are that such reservoirs 

 are filled with the first part of the rainfall and not with the last 

 part, and the water caught in them, if let alone, would be the first 

 to enter the streams, and probably would be well out of the way 

 down-stream before the last came. Could we build reservoirs with 

 draw-gates so that we might let the first storm water run through 

 them and then close the gates and hold the last rainfall they would 

 undoubtedly be of service. 



In the arid and semiarid districts, where the rainfall is under 

 twenty inches per annum, some of the most severe local rain-storms 

 occur. The ground is usually dry and hard and parched, and the 

 rain-storms are so excessive that a large proportion of the total rain- 

 fall runs off the surface and down into the streams, causing exces- 

 sive local floods. In such regions reservoirs would be most 

 serviceable, because they could be built so as to hold a larger frac- 

 tion of the rainfall, and in a degree would compensate for the ex- 

 cessive rapidity of precipitation. In a climate such as is general 

 throughout the Mississippi valley, however, it is doubtful about 



