334 



CONSERVATION 



which it may be wasted or become 

 harmful to the point where it shall be 

 applied to some useful purpose. A mill 

 race is a diversion canal on a small 

 scale, and the Chesapeake and Ohio 

 Canal, which diverts a part of the wa- 

 ters of the Potomac to a channel where 

 they may be useful to navigation, falls 

 in a similar class. In connection with the 

 irrigation projects of the Reclamation 

 Service, diversion canals constitute an 

 important feature. In some instances 

 they lead directly from rivers which 

 are capable of furnishing sufficient 

 water at all stages ; in other instances 

 they lead from reservoirs where water 

 is stored to maintain the desired flow 

 when the tributary streams would be 

 inadecjuate to the purpose. In none of 

 these cases has the diversion canal any 

 special relation to the conservation of 

 water. It introduces a siding in the 

 general through route of circulation and 

 discharges its water freight at the point 

 where it is wanted. It serves in some 

 measure to regulate surface flow, but 

 that object is subsidiary to a major pur- 

 pose, which niay be power or irrigation 

 or navigation. 



Canalization is a method of river 

 control which consists in reducing the 

 river to the condition of a canal by the 

 introduction of dams, locks, and sluice 

 gates. The current of the open river is 

 then replaced by slack water. The dis- 

 charge is permitted through locks as 

 required by passing boats, or over 

 sluiceways when the volume of flood 

 run-ofif beconies greater than the 

 amount which can be safely stored in 

 any reach of the river between dams. 

 The most important project for canal- 

 ization is that of the Ohio River, con- 

 cerning which we may quote from the 

 report of a board of army engineers, 

 dated December 15, 1906.'' 



The board finds — 



that a si.x-foot navigation at low water can be 

 established in the Ohio River from Pittsburg 

 to Cairo by the construction of forty-five 

 locks with movable dams, at an estimated 

 cost of $50,962,266, in addition to funds here- 

 tofore appropriated and authorized ; that a 

 nine-foot navigation over the same length of 



river can be established by the construction 

 of fiftv-four locks and dams, at an estimated 

 cost of $63,731,488. * * * 



The board gives exhaustive consideration 

 to the question of present and probable com- 

 merce, both down stream and up, and it ap- 

 pears that the present commerce of the river 

 is approximately 9,000,000 tons per annum, of 

 which a large proportion is downstream. 

 Having in view the fact that a canalized river 

 offers an upstream navigation lower in cost 

 and quicker in transit than an open-river 

 project, the board, arguing from the known 

 natural resources of the section and its popu- 

 lation, concludes that a river improved by 

 this method will afford facilities for the 

 cheap exchange of mineral, agricultural, and 

 manufactured commodities, which from their 

 low value and bulk cannot be exchanged 

 unless such cheap facilities are offered, and 

 that there is every probability that the im- 

 provement of the Ohio River by canalization, 

 as proposed, would induce a very large future 

 commerce, which does not now exist, in 

 addition to retaining and greatly facilitating 

 and cheapening the commerce which the river 

 now bears. 



In discussing the maintenance of the 

 nine-foot project, the board estimates it 

 at $800,000 per annum, not including 

 the dredging of silt, which would ac- 

 cumulate in slack water, or at $1,000.- 

 000 per annum if this item be included. 



This project, which was reviewed and 

 recommended without qualification by 

 the Board of Engineers for Rivers and 

 Harbors, in a report dated October 18, 

 1907, has for its object the single pur- 

 pose of promoting inland navigation, 

 and it illustrates clearly the relation 

 which any plan for canalization of a 

 stream bears to the general problem of 

 water circulation. The plan deals with 

 the water after it has reached a navi- 

 gable river, when it is no longer a 

 question of control of surface waters, 

 but merely one of more or less efifect- 

 ively regulating their distribution and 

 flow. The delay which may be imposed 

 by storage in slack- water basins is not 

 an appreciable factor in reducing the 

 damage due to floods such as those 

 which now annually work havoc in the 

 Ohio Valley. Moreover, the project it- 

 self establishes interests which lie with- 

 in the zone liable to flood, and in pro- 

 portion as it is successful and stich in- 



■^6oth Cong., 1st sess., H. R. Doc. 492. 



