528 DISCUSSION: FORESTS, RESERVOIRS, AND STREAM FLOW 
Mr. Chitten- a measurement to be made at Sioux City. The result was 6920 cu, 
den. ft. per sec., or about sy cu. ft. per sec. per sq. mile. The water, 
though much clearer than ever seen without the ice covering, was still 
so turbid that it could not properly be called transparent. An inter- 
esting feature was the appearance of the underside of the blocks of 
ice removed to admit the current meter. Glassy as is the ice formed 
on still-frozen water, it was nothing to the polished smoothness of the 
nether surfaces of these cakes resulting from the continual sand- 
papering by the fine sediment in the water. 
Concerning the Upper Mississippi reservoir system, the writer reiter- 
ates his statement that he considers it of great public importance, 
and is an advocate of its extension; but that does not blind him to 
the fact that its value for industrial use far exceeds in importance, 
under present conditions, its value for either flood protection or navi- 
gation, or both. 
Mr. Leighton’s explanation of the flood of 1905 on the Upper Mis- 
sissippi is quite unnecessary. The writer’s point is’ very simple, viz., 
that a stream emerging from a natural lake never rises as high or falls 
as low in discharge as it would if the lake were not there. If, there- 
fore, the lake be dammed up at its outlet, but cannot be allowed to 
rise beyond a certain elevation, and if that elevation is once reached, 
any subsequent storm finding the lake in that condition must be run 
out as fast as it comes in. If it is a heavy, flood-producing storm, it 
may and probably will cause a greater outflow than it would in the 
natural condition of lake and river. To that extent, it may enhance 
flood conditions in the valley below. 
In like manner, the lengthy discussion of the writer’s remarks about 
wave propagation down the Ohio River does not affect in the least the 
simple point involved, viz., that if a reservoir cuts off the peak of a 
flood wave on any stream, the resulting diminution of discharge at 
any point below will never be as great as at the reservoir, because of 
the flattening out and lengthening of a wave as it moves down stream. 
The writer thought that Mr. Leighton had calculated the full reser- 
voir effect at all points below, and is still uninformed that he did not. 
If he did, his deductions were to some degree in error. 
Mr. Pinchot’s lengthy explanation of his illustration before the 
House Committee on Judiciary is quite irrelevant because it does not 
touch the point of the writer’s criticism, viz., that he had used an 
illustration to explain to a responsible body of public men the bene- 
ficial influence of forests upon stream flow, and in so doing omitted 
to apply it to the conditions of flood and drought, the conditions of 
paramount importance, and confined it to medium conditions, mid- 
summer showers, so to speak. His illustration, therefore, was incom- 
plete and misleading, and his explanation leaves the matter in no bet- 
ter shape than it was before, 
