Mr. Swain. 
372 DISCUSSION : FORESTS, RESERVOIRS, AND STREAM FLOW 
discharge of water from summer showers which will occur, first on one 
tributary and then on another, in such a way as to furnish to the main 
stream always a low-water flow greater than if the springs could all be 
kept up. The author objects to the illustration which Mr. Pinchot gave 
before the Congressional Committee, on the ground that he did not 
carry it far enough. If the author’s argument be carried to the very 
common case where no rain falls upon a given drainage basin for 
weeks, or for a much longer time than it takes for a drop of water to 
flow from the most distant source to the mouth, it would seem to lead 
to the conclusion that there would be no flow at all in the stream. In 
other words, the author would have the mills at Lawrence and Lowell 
depend for their summer flow, not upon keeping up the “springs and 
little streams” so far as possible by increasing, through the effect of 
forests, the percolation into the ground, but would have these mills 
trust to luck that the summer showers would be so distributed—coming 
first on the Nashua River basin, then on the Contoocook River basin, 
the Winnipesaukee basin, ete.—that there would be a good flow at 
Lawrence and Lowell. This would, of course, require most intelligent 
planning, for it would not do to have these summer showers, which 
are supposed to flow rapidly from the surface, come down the different 
tributary basins in such a way that the water would arrive at Law- 
rence and Lowell at the same time. They must be accurately timed 
and distributed with reference to the position and size of the tributary 
basin. 
Even a large drainage area, say 10000 sq. miles, may well have its 
main stream possess a length from most distant source to mouth, 
measured on the stream, of considerably less than 300 miles. If the 
average velocity of the stream is 1 mile per hour, which is low, it 
would take less than two weeks for a drop of water to pass from the 
most distant source to the mouth. Now, even in districts which have 
a summer rainfall, it frequently happens that an area as large as that 
mentioned is without rain in any part for months at a time, under 
which conditions, if the writer understands the author’s theory and 
his admission, even such a large stream would practically dry up. It 
would seem to be much more reasonable to depend upon some means of 
keeping up the springs and small streams, rather than upon the equal 
distribution of surface waters of summer showers from deforested areas. 
Of course, the larger the stream the greater the low-water flow per 
square mile, other things being equal, because the lowest flow from all 
tributaries will not arrive at a given point at the same time, partly 
owing, no doubt, to local rains; but it is illogical to argue from this in 
favor of deforestation, which admittedly reduces the lowest flow from 
these tributaries. The author here seems to be inconsistent. In dis- 
cussing floods, he considers an extreme condition, in which the floods 
from various tributaries arrive simultaneously at a given point, and 
from this he argues generally that forests increase the violence of ex- 
