The Red River Basin has its origins in Glacial Lake Agassiz. About 14,000 years ago during the Ice Age, the continental glacier covered the Basin. As glacial ice retreated northward, Glacial Lake Agassiz formed about 12,000 years ago. The lake drained to the south through what is now the Minnesota River valley, to the west through northern Saskatchewan to Alaska, and to the east to the Great Lakes.

Where drainage occurred was dependent upon the level of the lake and ice coverage. About 11,500-11,000 yeas ago, drainage occurred through the Minnesota River valley, until the level dropped to a point where drainage was blocked by a moraine between the Red River and Minnesota River valleys.

As glacial ice retreated further north, an outlet opened to the Great Lakes. Ice again advanced southward and about 9,900 years ago, drainage again occurred through the Minnesota River valley until about 9,200 years ago when water levels dropped to a point where drainage to the south was blocked. The Great Lakes outlet closed about 8,500 years ago, and drainage since has occurred in a similar pattern to current drainage.

The Red River Valley exists in what was the southwestern portion of Glacial Lake Agassiz, and what is now the center of the Red River Basin. The Red River Valley extends over 315 miles from Lake Traverse in the south to Lake Winnipeg in the north. It is 60 miles wide at its widest point.

The elevation of the Red River falls 233 feet from the headwaters of the Red River to its mouth 545 river miles away, for an average slope of only about one-half foot per mile. The slope is greater near the headwaters and flattens toward the mouth. The elevation of the Valley in the south is 943 feet mean sea level (msl), while at the northern end, the elevation is 714 msl -- a change in elevation of 229 feet over its 315 mile length.

(Information Sources: "A River Runs North" by Gene Krenz and Jay Leitch, Red River Water Resources Council (1993), and "Aquatic Communities and Contaminants in Fish from Streams of the Red River of the North Basin, Minnesota and North Dakota" by Robert Goldstein, U.S. Geological Survey (1995). Map Source: "A River Runs North," Figure 1-2.)

More Information

For questions about the Red River Basin information available on this Web site, contact Molly MacGregor at 218-846-0494.