Wisconsin v. Illinois
Headline: Court allows temporary diversion of Great Lakes water into Illinois Waterway and Mississippi River, authorizing up to an average 8,500 cubic feet per second through February 28, 1957 to ease navigation
Holding: In view of the continuing navigation emergency, the Court temporarily modified its 1930 decree to allow diversion up to an average of 8,500 cubic feet per second (plus domestic pumpage) through February 28, 1957, under Army Corps direction without prejudicing other legal rights.
- Permits temporary diversion of Great Lakes water into Illinois Waterway and Mississippi River.
- Empowers Army Corps to set timing and amounts up to 8,500 cfs.
- Order is temporary; original decree returns after February 28, 1957.
Summary
Background
Several States are involved: Wisconsin, Ohio, Michigan, and New York are listed as complainants; Illinois and the Metropolitan Sanitary District of Greater Chicago are listed as defendants; Mississippi intervened, and the United States filed a memorandum as amicus. The opinion references an existing decree issued April 21, 1930 and a continuing emergency in navigation caused by low water in the Mississippi River.
Reasoning
The Court considered whether to temporarily modify Paragraph 3 of its 1930 decree to respond to the navigation emergency. The Court issued a temporary modification allowing diversion from the Great Lakes–St. Lawrence System into the Illinois Waterway and the Mississippi River. The diversion is capped at an average of 8,500 cubic feet per second, in addition to domestic pumpage, and only in amounts and at times the Army Corps of Engineers decides will help navigation without seriously interfering with navigation on the Illinois Waterway. The order also states it does not prejudice any party’s legal rights about other diversions.
Real world impact
The order gives the Army Corps practical authority to move water to help ships and barges during the current low-water emergency, subject to the 8,500 cfs limit and attention to Illinois Waterway navigation. The change is explicitly temporary and expires on February 28, 1957, after which the original 1930 decree provisions remain in force until the Court says otherwise. This means the arrangement can ease immediate navigation problems but is not a final, permanent change to long-term water rules.
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