so, about 20 to 40 million acre feet are oxygen 
deficient. 
An alternate calculation based on a 270 million 
pound oxygen deficit suggests that 20 million acre 
feet could be seriously depleted.’* These values 
are in sufficient agreement for purposes of this 
analysis. 
The conclusion, then, is that artificial destratifi- 
cation of Lake Erie will require displacement of 
about 40 million acre feet of bottom water, which 
must be brought to the surface to be replaced with 
surface water during the summer months (i.e., 
about 100 days). 
Artificial destratification is not a new concept, 
but application on the scale represented by Lake 
Erie requires new considerations. Numerous de- 
stratification tests have been conducted in the 
United States, Great Britain, and Europe. Whether 
any permanent installations have been made is 
unknown. 
Results of these experiments have not always 
been predictable, probably due to the nature of 
sediments and the initial oxygen content. This 
experience emphasizes the obvious need for 
caution in any major effort to change the environ- 
ment. A direct parallel can be seen in large-scale 
weather modification programs. 
The use of airlift recirculators has been de- 
scribed, and detailed design methods have been 
developed. Airlift recirculators (vertical, open- 
ended pipes with compressed air introduced near 
the bottom end and discharging below the surface) 
are extremely efficient movers of water against 
essentially zero head. For example, air consum- 
ption rates are approximately one-hundredth of a 
cubic foot per minute per gallon of water circu- 
lated per minute. Velocities issuing from the 
circulator will be from five to six feet per 
second.*® 
Application to the destratification of Lake Erie 
obviously requires considerable extrapolation. This 
is particularly true of the induced circulation that 
occurs outside the circulator. Another expert 
estimated that the net induced circulation may be 
14Commoner, B., “The Killing of a Great Lake,” The 
1968 World Book Supplement to the World Book 
Encyclopedia. 
1S Cook, M. W. and E. D. Waters, Operational Charac- 
teristics of Submerged Gas Lift Circulators, U.S. Atomic 
Energy Commission Report HW-39432, Dec. 1, 1955. 
VI-132 
as large as 20 times that calculated by the design 
method; however, for purposes of this analysis, 
this value is not applied. 
Using the design methodology of Cook and 
Waters!® and the aforementioned volume of water 
to be circulated (i.e., 40 million acre feet in 100 
days), the following values result: 
Engineering Parameters 
Volumetric water rate 200,000 CFS!” 
Diameter of circulators 10 feet 
Length of circulators 50 feet 
Number of circulators 500 
Compressed air volume 
(total) 1,300,000 SCFM?® 
Compressor horsepower 
(HP), total 600,000 
Cost Parameters 
Capital costs 
Circulators @ $200,000 $100,000,000 
Annual operating costs 
Fuel (diesel) 8,150,000 
Amortization (10 yrs. st. line) 10,000,000 
Maintenance and repair 5,000,000 
Personnel 5,000,000 
$28,150,000 
For contingency purposes, this total value can be 
rounded upward to $30 million per year. 
As presently conceived, airlift circulators would 
consist of vertical, open-ended riser tubes mounted 
on barges. Power for compressing the motive air 
introduced near the riser’s bottom would be 
provided by diesel engines—approximately 1,000 
hp per circulator. Each riser would be 50 feet in 
length with the upper end terminating about 10 
feet below the surface. Blowable ballast tanks at 
the lower end of the riser will allow the riser tube 
to be elevated for moving into shallow water for 
repair and storage. With the ballast tanks flooded, 
16 Ibid. 
'7CFS is cubic feet per second; 200,000 CFS is 
approximately equivalent to the average annual flow of 
the Columbia River at its mouth. 
18SCPM is standard cubic feet per minute; standard 
refers to the conditions of average atmospheric tempera- 
ture and pressure. 
