102 



THE IMPROVEMENT OF RIVERS. 



floods occurred when such reservoirs, had they been in existence, would have been full. 

 Such being the case, they could not have materially aided in restraining those floods, 

 and this would certainly be the case, almost every year owing to the irregularity of the 

 periods when great floods occur. 



" If by possibility there could be a gigantic dam 400 feet high at Wheeling, suffi- 

 cient actually to stop and absolutely to control all the water of the 27,337 square miles 

 of drainage above Wheeling, it could not restrain any portion of the flow from the 

 remaining 189,663 square miles of the Ohio valley, nearly seven times the area. We 

 should even then have control of only about one-ninth of the Ohio River territory. 

 As a practical engineer I cannot hesitate, therefore, in expressing the opinion, that the 

 scheme of controlling or equalizing the floods of the Ohio River by means of artificial 

 reservoirs is certainly impracticable; and that in any merely human view of the ques- 

 tion it is practically an engineering impossibility." 



This reasoning is applicable to many other cases as well as to that of the Ohio. 



After the inundations which devastated France in 1846, 1856, and 1866, the ques- 

 tion of reservoirs was widely discussed, as mentioned farther on, but their excessive cost 

 prevented their application on a great scale, and a French authority has in recent 

 years stated that "the idea of modifying immediately the regime of inundations by 

 the creation of a system of reservoirs is now considered as unrealizable." 



The question of storage reservoirs has been exhaustively entered into by a recent 

 Government report, from which the following extracts have been made : * 



Natural Reservoirs. " Nature presents abundant examples of the effective control 

 of stream-flow through the agency of reservoirs. There are indeed comparatively few 

 streams whose flow is wholly uninfluenced by such action. The most perfect example 

 in the world, both as to the magnitude of the stream and the completeness of control, 

 is the St. Lawrence River, embracing the great chain of North American lakes. Con- 

 sidering only that portion of the system which lies above the Falls of Niagara, let the 

 flow at the outlet be compared with that of other streams of similar magnitude. For 

 this purpose take the Niagara River at Buffalo, the Ohio at Paducah, Ky., the Missouri 

 at its mouth, and the Mississippi just above the mouth of the Missouri. The following 

 table gives the area of watershed in square miles and the mean annual discharge in 

 cubic feet per second of each: 



" The above discharge for the Niagara River is based upon twenty-five years' 

 record (1871-1895); that for the Ohio and Upper Mississippi upon six years' record 

 '1880-1885); and that for the Missouri upon twelve years' record (1879-1890). 



* Reservoir Sites in Wyoming and Colorado, Captain Hiram S. Chittenden, Corps of Engineers, U. S. A , 

 House Doc. 141, 55th Congress, ad Session. 1898. 



