336 A NATIONAL PLAN FOR AMERICAN FORESTRY 



posure, the more nearly are conditions reduced to those existing on 

 clean-tilled land. 



Erosion is unquestionably responsible for the major part of the 

 expenditure to maintain channels in the Delaware River, as has been 

 previously described. Erosion has its effect on water storage, for 

 municipal supplies and power. In 1915 the State forester of Mary- 

 land described as follows the results of erosion along the Patapsco 

 River in his State : 



Between Relay and Alberton, a distance of 11.4 miles, there are 10 water- 

 power developments, 8 of which are now in operation. Power for these plants 

 is furnished by the Patapsco River, and its value for that purpose is measured 

 by the evenness of flow and freedom from silt * * *. The steep slopes 

 along the river that have been cultivated in years past have largely contributed 

 to the accumulation of silt which has collected behind the dams built for storage 

 purposes and has clogged the river channels, increasing the frequency of floods 

 and carrying immense quantities of silt into the upper Patapsco near Baltimore, 

 requiring the expenditure of large sums of money for dredging. 



Another erosion problem of considerable local importance in the 

 northeast is not created by water, but by wind. The shores of 

 both the Atlantic Ocean and the sheltered bays behind sandy spits 

 are used for recreation by enormous numbers of people. In places 

 drifting sands have seriously interfered with this use. Efforts have 

 been made to control the dunes on Cape Cod and at various other 

 places along the coast, but individual effort has not been effective 

 in the face of a problem common to many owners of shore properties. 

 The need for studied and concerted effort is emphasized by the 

 constant increase in number of the recreationists. Not less than 

 500 miles of coast line is involved in varying degree. 



FLOODS 



Low water during the summer in streams used for municipal 

 supplies, for generation of power, and for navigation, is scarcely 

 more of a problem in the region than is high water at other times 

 of the year. Parts of the northeast have suffered very greatly 

 from floods. The 1907 report of the Water Supply Commission of 

 Pennsylvania stated that: 



Pennsylvania is one of the worst sufferers from floods among the eastern 

 States * * *. It is not alone the large streams on which damage has been 

 wrought, for many of the smaller streams overflow their banks with disastrous 

 results, and in such cases the damage has been increased by the failure of dams 

 or embankments, thus releasing the additional water into the already over- 

 flowing channel. 



The North Branch of the Susquehanna River has repeatedly in- 

 undated the city of Wilkes-Barre, and the floods of 1902 and 1904 

 in this stream destroyed $1,300,000 worth of bridges alone, as well 

 as millions of dollars worth of other property. According to a report 

 made in 1931 by the New Jersey State Water Policy Commission, 

 a repetition of the 1903 flood in the Passaic River would today cause 

 a damage of over $42,000,000. Such floods in the Passaic may be 

 expected only about once in 200 years, but a flood causing $1,000,000 

 worth of damage will occur on the average once every 5 years, and 

 one causing over $2,500,000 damage every 10 years. The com- 

 mission concluded that the values at stake in this watershed justify 

 the expenditure of $93,000,000 on channel improvements. The 

 New England flood of the fall of 1927 took 88 lives and caused 



