1905 



FORESTRY AND IRRIGATION 



311 



series of terraces from base to sum- 

 mit. On the drainage basin as a whole 

 the grade of slope averages 13.05 per 

 cent, or double that of the Wallkill, 

 and the fall of the stream 59.6 feet per 

 mile, or nearly six times that of the 

 Wallkill. These figures express in 

 themselves the comparatively steep, 

 rugged character of the topography 

 of this basin. 



In another important respect these 

 two streams differ widely in topo- 

 graphy. That of the Esopus is not 

 only steep and rugged ; it is simple and 

 direct in character. The tributary 



iate, lies in the facilities for storage 

 by natural reservoirs. Natural res- 

 ervoirs form a marked feature of the 

 Wallkill basin. The undulating to- 

 pography, together with the alterna- 

 tion of areas of soft limestone with 

 more resistant shale, have led to the 

 formation of swamps and ponds all 

 over the drainage of this stream. Of 

 special note are the "Drowned Lands" 

 which impede the course of the river 

 at its very source and line the chan- 

 nel of the main stream for many miles. 

 On the entire Wallkill basin 42.52 

 square miles, or 5.04 per cent, of the 



The Lower Wallkill Basin 



streams are few in number, compara- 

 tively short, and direct in their course. 

 The rolling valley of the \Yallkill on 

 the other hand is cut up into a series 

 of long, winding, tributary basins, 

 forming an extensive, complex drain- 

 age system with many secondary 

 streams of gentle fall and sluggish 

 current. 



A third and still more striking dif- 

 ference in the topographic conditions 

 upon these two basins, and one whose 

 effects upon the character of stream 

 flow are necessity, direct and immed- 



total area, are occupied bv lakes, 

 ponds, or swamps. Xntural reser- 

 voirs so well distributed ard having 

 so large a total extent, form a factor 

 of prime importance in regulating the 

 llo\v of the river. 



The steep, rugged basin of the 

 Ksopus, on the other hand, is practi- 

 cally devoid of natural reservoirs. 

 Swamps and ponds, forming no ap- 

 preciable part of its entire area, are so 

 limited as to have no effect upon nat- 

 ural storage. 



The contrast in topography condi- 



