290 FORESTS, RESERVOIRS, AND STREAM FLOW 
storage reservoirs as an aid to navigation was originally proposed by 
General G. K. Warren, and was first put into definite shape by the late 
Colonel F. U. Farquhar, M. Am. Soe. C. E., of the Corps of Engineers. 
The plan then embraced a large number of lakes in Minnesota and 
Wisconsin, but only five sites have actually been improved. The dams 
were first built of timber cribs, but have recently been rebuilt in con- 
crete, as shown on Plate XLII. The combined storage is about 93 billion 
cu. ft. It is about twice the mean annual run-off from the water-shed, and 
the system is probably the only one, except the Great Lakes, which 
equalizes periodic as well as annual fluctuations of flow. That is, it 
carries over the surplus from wet years to help out in dry years, and 
its utility is, therefore, of the most comprehensive character. The 
cost of the five reservoirs ig remarkably low, although it is not now 
possible to tell the exact cost of the present structures on account of 
the mixture of old and new work; but it probably does not exceed 
$750 000, including a lock in the Sandy Lake Dam. This is only $8 
per 1000000 cu. ft., or 35 cents per acre-foot on the basis of total 
capacity. It would be about twice this on the basis of the mean annual 
run-off from the water-sheds. 
A large portion of the original project has been abandoned because 
public sentiment did not support its continuance. The writer has 
always regretted this backward step, as he believes in developing to 
the fullest extent the exceptional opportunities here offered for the 
storage of water. The available reservoir sites which could be cheaply 
improved in Minnesota and Wisconsin are sufficient to control abso- 
lutely the floods of the Mississippi within the danger line, for a long 
distance below St. Paul, and to improve the navigation of the upper 
river very materially, while their value for industrial purposes is almost 
beyond estimate. 
In spite of the great and obvious advantages of this system, it has 
not yet received the popular approval that might be expected of it. 
In fact, about three years ago, there arose a widéspread sentiment in 
the community around the reservoirs that the system was, on the whole, 
injurious, that its disadvantages far offset its advantages, and a strong 
movement was organized to have it abolished altogether. For the 
purpose of investigating this matter, a Board-of Engineers was ap- 
pointed, of which the writer was a member. The Board found that 
there was a general belief among the people below the dams that 
