DISCUSSION: FORESTS, RESERVOIRS, AND STREAM FLOW 357 
and all villages, bridges, canals, and other structures along the banks mr. Harts. 
would be swept away in the general flood. One such disaster might 
easily be considered to outweigh all the benefits received or expected 
from the entire system. 
Let us now examine into the effectiveness of the system. In addi- 
tion to the statement of a board of engineers that the reservoir system 
on the head-waters of the Mississippi was producing benefits probably 
commensurate with its cost, and hence should not be abandoned,* 
we also have the statements of two former boards which, after mature 
consideration, recommended against the extension of the system to other 
rivers. Although the Mississippi reservoirs are the largest in the 
world used for such purposes, the increase in navigable depth at St. 
Paul, 350 miles down stream, is only a little more than 1 ft. at low 
water. In the Annual Report of the Chief of Engineers for 1881, 
p. 2758, is found the following: 
“In recapitulation, the conclusions of the Commission may be 
stated as follows: 
“First. The system of works in progress on the Mississippi River 
between St. Paul and the mouth of the I]linois River, with the modifi- 
cations which experience will suggest, is adequate for the improve- 
ment of navigation, and should be pushed rapidly to completion. 
“Second. A sufficient improvement of the river is not to be ex- 
pected from the action of a system of reservoirs alone. 
“Third. It is possible that on the completion of the observations 
now in progress, some of the proposed reservoirs which furnish water 
at the least cost, may be found to be economical aids to the principal 
system of channel contraction. But they should only be built when 
the works for channel contraction approved have been carried to the 
fullest economical development.” 
In the Annual Report of the Chief of Engineers for 1887, p. 1692, 
is found the following (referring to the Mississippi River): 
“The region already occupied by reservoirs is exceptionally well 
suited for the system, and the dams have accomplished all that was 
reasonably to be expected from them. They now ‘adequately improve 
navigation’ in the sense that they render a fair return for their cost; 
and in the opinion of the Board they should be completed by raising 
the Pokegama Dam 2 feet and by building a dam in the Sandy Lake 
district, as recommended by Major Allen, if more elaborate surveys 
there confirm present indications. 
“The Board does not favor the extension of the system to the 
St. Croix, the Chippewa, and the Wisconsin at present. It is believed 
that funds applied to the bed of the river in contraction works, dredg- 
ing crests of troublesome bars, etc., will yield a better return. That 
method has proved effective so far as applied to the Upper Mississippi, 
and it will be soon enough to consider the advisability of re- 
inforcing it by new reservoir systems when the necessity therefor has 
been demonstrated.” 
*Annual Report, Chief of Engineers, 1906, p. 1470 
