REGULARIZATION. 55 



end and filled in at the lower end; the mean slope has therefore become less. This 

 seems to be a certain result of contraction, no matter under what theories the works 

 themselves are planned. In regard to this De Mas says:* " In a stream with a movable 

 bottom, a continuous diking, diminishing the width of the section, produces the 

 following effects: Toward the upper end a lowering of the bed takes place, and this 

 has as a consequence a corresponding lowering of the bottom of the plane of the 

 water. Toward the lower end there occurs a raising of the bottom of the plane of the 

 water. In all the diked part a diminution of the mean slope of the bottom and sur- 

 face takes place." 



As has already been stated, regularization works have been constructed on a large 

 scale in Germany, and the result of these works has been an enormous development 

 of navigation on the principal rivers of the empire. On the Rhine the development 

 of such works began about three-quarters of a century ago. The system adopted was 

 that of spur-dikes placed close together, longitudinal dikes, parallel dikes, dredging 

 in the river-bed, and bank protection. Similar works, but with much less development, 

 have been established on the Elbe and Oder, and on other rivers. 



In the beginning the realization of a normal profile and a uniform slope were 

 aimed at, but later studies and experience produced an evolution in ideas. Prof. 

 Schlichting has laid down the following principles upon which rests the German system 

 of regularization: ;._" 



ist. Construction at the convex banks of spur-dikes, and in the concave curves 

 of protection dikes and dikes parallel to the banks, with the use of inclined submerged 

 spurs to close unusual depths. 



2d. Transformation of slight sinuosities into right lines, adopting the best possible 

 location of the channel in the navigable bed. 



3d. Systematic alternation corresponding to the alternation of convexities and 

 concavities, the spur-dikes being on one bank with works of protection and dikes on 

 the other. 



4th. Contraction of the width of the river by the advancing into the bed of convex 

 curves, accompanied by a small flattening of concave curves. 



5th. Diminution of the mass of material transported in the navigable channel, 

 to be accomplished by the consolidation of banks of alluvium in the convex parts. 



In regard to these works it is stated on good authority that " the incontestable 

 fact is that by adopting a process of exploitation appropriate to the navigation, the 

 Germans have succeeded in serving an enormous traffic with relatively small depths; 

 and on the other hand it is certain that the works of regularization built have been in 

 general relatively of small expense." 



It would seem from the foregoing that it is possible to deduce certain general 

 conclusions upon the regularization of streams, and De Mas f undertakes this as follows . 



* "Riviferes Courant Libre," p. 325. f Ibid. 



