THE IMPROVEMENT OF THE MISSISSIPPI RIVER. 329 



The second systen of protection is that now in vogue, or levees high enough 

 to hold ordinary floods, but great floods always breaking through them. This 

 is both expensive and unsatisfactory. It is a protection that costs millions of 

 dollars and yet does not protect. 



The third method is to build the levees high enough and strong enough to 

 stand the greatest flood that would likely come upon them. As to the heights 

 the flood would have reached had the water all been confined to the channel, 

 the estimates of Gen. Comstock, President of the Mississippi River Commission, 

 were taken and are as follows : 



At Columbus, Ky. , there would have been added 200,000 cubic feet per 

 second to the channel discharge, giving an increased height of three feet. At 

 Fulton, Tenn., with 600,000 cubic feet to be added, the increased stage would 

 have been 10 feet. At Helena 360,000 cubic feet would have been added, giving 

 an increased stage of four feet. At Lake Providence the discharge of 1,000,000 

 cubic feet would have been nearly doubled, giving an increased stage of 10 feet. 

 At Red River Landing there was 1,600,000 feet passing in the main channel, 

 300,000 cubic feet passing in the Atchafalaya, and 300,000 more passing over- 

 land. If this amount of overflow water were divided proportionately between 

 the two streams it would raise them both three feet. 



At New Orleans the maximum discharge was 900,000 cubic feet per second. 

 If the discharge at Red River of 1,600,000, increased by 200,000 cubi'c feet of 

 overflow water, were all confined below that point the discharge at New Orleans 

 would be doubled. The increased height of the water is somewhat imcertain, 

 but it would probably be about 10 feet. 



The mouth of Red River is probably the head of the Delta, and an eff'ort 

 now to confine all the water to one or two channels will demand enormously high 

 levees. And yet Captain Eads resigned his place on the commission because 

 they declined to close the Atchafalaya entirely, and so deprive that part of the 

 river of this partial relief. The increase of stages given are all so much above 

 the high- water marks of 1882. 



Levees calculated to confine the greatest floods must be on an average six- 

 teen feet high where there are now none, and all levees now built must be raised 

 on the average by eight feet. The cost of a proper levee is $50,000 per mile, 

 which means a total expenditure of some $50,000,000 to confine such a flood as 

 that of 1882 to the channel from Cairo to the Gulf, allowing, also, the Atcha- 

 falaya to discharge its full capacity. 



The River Commission has estimated $11,000,000 for this work. This low 

 estimate is the occasion of Gen. Comstock's exceptions to the report. 



The third method of protection is more feasible. The features of this system 

 are moderate-sized levees, or such as will keep out all moderate or ordinary floods, 

 or such levees as are now found. Provision made for the discharge over these 

 levees of the excess over the channel's capacity, in case of high floods, without 

 injury to the levee, and provision for the conveyance of this flood overflow back 

 to the channels of the bottoms. Levees of this size would probably furnish com- 



