In order to alleviate water damage on the shoreline of Lake Michigan and others of the Great Lakes during periods of abnormally high water levels in the Great Lakes, and to improve the water quality of the Illinois Waterway, the Secretary of the Army, acting through the Chief of Engineers, is authorized to carry out a five-year demonstration program to temporarily increase the diversion of water from Lake Michigan at Chicago, Illinois, for the purpose of testing the practicability of increasing the average annual diversion from the present limit of three thousand two hundred cubic feet per second to ten thousand cubic feet per second. The demonstration program will increase the controllable diversion by various amounts calculated to raise the average annual diversion above three thousand two hundred cubic feet per second up to ten thousand cubic feet per second. The increase in diversion rate will be accomplished incrementally and will take into consideration the effects of such increase on the Illinois Waterway. The program will be developed by the Chief of Engineers in cooperation with the State of Illinois and the Metropolitan Sanitary District of Greater Chicago. The program will be implemented by the State of Illinois and the Metropolitan Sanitary District of Greater Chicago under the supervision of the Chief of Engineers.
During the demonstration program a controllable diversion rate will be established for each month calculated to establish an annual average diversion from three thousand two hundred cubic feet per second to not more than ten thousand cubic feet per second. When the level of Lake Michigan is below its average level, the total diversion for the succeeding accounting year shall not exceed three thousand two hundred cubic feet per second on an annual basis. The average level of Lake Michigan will be based upon the average monthly level for the period from 1900 to 1975.
When river stages approach or are predicted to approach bankfull conditions at the established flood warning stations on the Illinois Waterway or the Mississippi River, or when further increased diversion of water from Lake Michigan would adversely affect water levels necessary for navigational requirements of the Saint Lawrence Seaway in its entirety throughout the Saint Lawrence River and Great Lakes-Saint Lawrence Seaway, water shall not be diverted directly from Lake Michigan at the Wilmette, O’Brien, or Chicago River control structures other than as necessary for navigational requirements.
The Chief of Engineers shall conduct a study and a demonstration program to determine the effects of the increased diversion on the levels of the Great Lakes, on the water quality of the Illinois Waterway, and on the susceptibility of the Illinois Waterway to additional flooding. The study and demonstration program will also investigate any adverse or beneficial impacts which result from this section. The Chief of Engineers, at the end of five years after October 22, 1976, will submit to the Congress the results of this study and demonstration program including recommendations whether to continue this authority or to change the criteria stated in subsection (b) of this section.
For purposes of this section, controllable diversion is defined as that diversion at Wilmette, O’Brien, and Chicago River control structures which is not attributable to leakage or which is not necessary for navigational requirements.