Forest Influences 307 



many of our rivers, disastrous spring floods have developed 

 in these streams that do a tremendous amount of damage 

 both to shore property and to navigation. Later in the 

 summer the water in these same streams reaches such a 

 low level that navigation is again impeded and water 

 power seriously disabled. The floods, formerly unknown, 

 that have of recent years become of annual occurrence in 

 the southern Appalachian mountains are said to damage 

 improved property alone to the extent of ten million 

 dollars annually. The spring flood and consequent sum- 

 mer drought in the Allegheny and Monongahela rivers 

 above Pittsburgh, besides the enormous damage done in 

 that city and in the Ohio valley, greatly impair the navi- 

 gation of the Ohio River for five months. Floods in the 

 spring make navigation dangerous, and in the summer 

 there is not sufficient water for the larger boats to get into 

 the upper stream. If the water that now flows down the 

 Ohio in a year were evenly distributed throughout the 

 seasons, the now coveted nine-foot level would be main- 

 tained the year round at Pittsburgh and the navigation 

 of the river would be perfectly safe for the largest boats at 

 all times. 



All these flood and drought phenomena are now proved, 

 as far as such a thing can be proved, and generally ad- 

 mitted to be the result of the removal of the forests from 

 the water-sheds. Moreover, as has been proved by many 

 observations in all parts of the world, springs are affected 

 in the same way as the rivers. There were very many ex- 

 amples of this in India. As the forests were cleared away, 

 the flow of the springs became less and less each dry season 

 until it was finally as dry as the remainder of the country. 



