156 GEOI^OGICAI^ SURVEY OF NEW JERSEY. 



the size of the water-shed is less. This fact appears throughout 

 the table, and allowing for this it is impossible to detect any 

 relationship between the maximum rate of discharge and the 

 percentage of forest on the catchment. The relative height of 

 a flood, as generally understood, and its destructiveness, are 

 accurately measured by the maximum discharge above shown. 

 On two catchments fairly similar in topography, one of which is 

 largely forest-clad and the other deforested, the forest-clad water- 

 shed should show a lower rate of flow if forests exert a control- 

 ling effect ixpon such extreme floods. The Ramapo at Pompton 

 and the Paulinskill at Hainesburg seem to be fairly comparable. 

 The former with 75 per cent, of forest shows a maximum rate of 

 54, while the latter with 27 per cent, of forest shows a maximum 

 rate of but 26. Again, the upper Ramapo with 80 per cent, of 

 forest shows a maximum rate of 56, while the Wanaque with 85 

 per cent, of forest shows a rate of 99, and the Pequannock, with 

 78 per cent, of forest, a rate of 115. The Pequannock shows 

 about the same maximum rate as the South Branch at High 

 Bridge, although the latter has only 30 per cent, of forest. 

 There are enough of such instances to entirely break the force 

 of the cases in the table which seem to show a higher rate for a 

 less percentage of forest, such as the Pompton and the south 

 branch of the Raritan, or the Whippany and Upper Musconet- 

 cong, and the conclusion is inevitable that any effect which 

 forest may have upon the maximum rate of discharge is entirely 

 subordinate to other controlling influences which we have stated 

 to be mainly topographic. 



The destructive character of the flood under consideratiton,. 

 which in most places seems to have been higher than any 

 previously recorded, has, as usual, been freely attributed tO' 

 deforestation. We repeat our caution that the mere fact that a 

 flood is higher at a given point than heretofore, does not mean, 

 necessarily, that its rate of discharge was greater, but may mean 

 that the valley has been artificially obstructed during recent 

 years by bridges, dams or embankments. Admitting, however, 

 that this flood generally had a higher rate of discharge, we must 

 bear in mind the absolute dearth of evidence either that the area 

 of forest is less, or that its condition is in any way inferior to 

 that of 1850. 



