806 FORESTS, RESERVOIRS, AND STREAM FLOW 
oping this power through public agencies and preserving it from private 
ownership and control. His present criticism is directed not at all at 
the principle involved, but at the extravagant expectations now being 
fostered as to the possible revenue which the Government may derive 
from such development. 
The quantity of power estimated in the publications of the Geo- 
logical Survey and the Agricultural Department are based upon an 
assumption that most engineers will question, viz., that 90% of the 
fall of our rivers can be utilized in effective head upon water-wheels. 
This is too great a figure. The most thoroughly developed river in the 
United States, namely, the Merrimac, in New Hampshire and Massa- 
chusetts, develops only 70% of the total head. Taking all the streams 
into consideration, it seems hardly possible that more than 50% of the 
fall can be utilized. When the fall of a river is uniform, even if quite 
steep, the cost of long canals or high dams necessary to concentrate it 
at one point often prohibits development altogether. From altitudes 
of 3.000 ft., the Missouri and Yellowstone, for example, descend to the 
sea with a total energy of possibly 5000000 h.p.; yet comparatively 
little of this can be developed advantageously. It is only in those 
places where Nature has helped out by concentrating the fall at cata- 
racts or rapids that water-power development is commercially profitable. 
At low dams, such as are ordinarily built at lock sites, the head is 
often nearly all obliterated during high water. How far storage may 
affect these drawbacks cannot be said, but it should, of course, help a 
great deal. The official estimates of flow for non-regulated streams 
are based on two weeks’ average lowest flow. This may probably. be 
extended materially with reservoir aid or supplementary steam power. 
Possibly the total estimated horse-power may ultimately be realized.* 
When it comes to the royalty which the Government may receive 
for these water-powers, if developed by private interests, the price of $20 
per horse-power, adopted by the Geological Survey and the Agricultural 
Department, is wholly out of the question under present conditions. 
Possibly the writer does not understand what the figure is intended 
to embrace. From Mr. Leighton’s articles, the inference has been 
drawn that wherever the work of the Government renders power 
*There has recently been invented a device called a fall increaser, an adaptation 
of the Venturi meter, by Clemens Herschel, M. Am. Soc. C. E., which promises to 
utilize the extra flow of streams in time of flood water and low heads to increase 
and maintain the head upon the wheels. If this invention proves a success, as 
seems probable, it will be an immense gain to all water-powers of low head subject 
to ae ca as would doubtless be the case in very many of those under 
consideration. 
