HYDROLOGY OF NEW YORK 



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success, as, owing to the winding course of the river, the floods 

 confined at one point escaped at another, and took their defenses 

 in reverse. This deplorable condition of the Rhine valley con- 

 tinued until the commencement of the present century, when the 

 population, already greatly reduced by poverty and disease, was 

 daily decreasing owing to emigration to America. 



Colonel Tulla, of the engineers, an eminent authority on 

 hydraulics at that time, by repeated and unremitting exertions, 

 induced the government, in 1817, to undertake a thorough survey 

 of the entire Rhine valley. Upon that survey was based the 

 project for the radical regulation of the Rhine bed, which was 

 approved and ratified by treaty between the border states of 

 France, Bavaria and the Grand Duchies of Baden and Hesse, 

 and according to which the regulation of the Rhine was carried 

 out during the years 1819-1863. 



The work consisted in regulating the course of the river and 

 making it more direct. This necessitated the excavation of 

 twenty-three considerable cuts, which reduced the distance by 

 river between Mannheim and Basle from 252 to 169 kilometres, 

 and increased the fall 30 per cent. Further, the stream was 

 confined to a uniform channel of suitable section, both banks 

 w T ere substantially protected, the old river bed and all branches 

 were filled in, and the land thus reclaimed was for the most part 

 brought under cultivation. 



The above mentioned regulation of the Rhine may be con- 

 sidered one of the most extensive and interesting undertakings 

 of the kind ever attempted in Europe. It is proved that the 

 following advantages have been secured: 



a) The river has undeviatingly followed the new course pro- 

 vided for it ; has deepened its bed to the extent of two metres in 

 some places, and lowered the mean water-level proportionately. 

 Flood-water also has been passed more quickly. 



b) The general water-level being thus reduced in hight, ex- 

 tensive tracts of swampy ground have been laid dry and con- 

 verted into fertile arable land. Further, more than 20,000 hec- 

 tares of old river bed, water-holes and sandbanks have been 

 reclaimed, and brought in a great measure under cultivation; 

 and lastly, the low-lying tracts are now no longer exposed to 

 inundations. 



c) The sanitary condition of the Rhine valley has visibly im- 

 proved, and the general prosperity of the inhabitants materially 

 increased. 



d) According to the concurrent reports of experts, govern- 

 ment officials and local authorities, the benefits derived from the 

 regulation of the Rhine are so considerable that the capital laid 



