POLLUTION OF THE POTOMAC RIVER, 



By F. H. Newell, 



Clilcf IlydrograpJier, U. S. Geological Surveg 



The facts concerning the pollution of the Potomac river are 

 of peculiar concern to the residents of Washington because of 

 the fact that the supply for domestic and municipal use is de- 

 rived mainly from that stream, only a small portion being ob- 

 tained from wells or springs. This water we know to be polluted, 

 but opinions differ widely as to whether these pollutions are 

 negligible or may be sources of ever-present danger to the com- 

 munity. 



In order to discuss the subject intelligibly it is necessary to 

 have clearly in mind the situation of the catchment basin of the 

 river, as well as the relative position of the various tributaries 

 and of the principal towns and political divisions. We of course 

 know that the Potomac is one of the principal rivers of the At- 

 lantic slope, receiving the drainage from an area which lies about 

 midway of the eastern side of the United States. It rises in the 

 Alleghany mountains, its drainage basin embracing portions of 

 the states of Pennsylvania, Maryland, West Virginia, and Vir- 

 ginia. At this part of the system the mountains have a general 

 trend a little north of northeast, the narrow valleys between the 

 ridges are nearly parallel, and thus the streams coming from the 

 mountain sides unite in creeks or rivers flowing either north- 

 easterly or southwesterly. Taking the Potomac basin as a whole, 

 by far the greater number of the tributaries flow toward the north- 

 east, the streams coming from the northern part of the basin 

 being relatively small. The main river itself, receiving from 

 point to point the tributaries from each side, cuts directly across 

 the mountains, having a southeasterly direction, although in 

 detail its course is quite crooked. 



The absence of lakes, marshes, and broad valleys renders the 

 tributary streams rapid in their delivery of precipitation upon 

 the basin, the Potomac being subject to sudden floods, and the 

 dry season discharge being very small. For this reason the river 

 as a source of power is not so valuable as might be expected 

 from the size of its drainage area. At the points where the river 



