Master Drainage During Deglaciation

As occupying the middle of the main lobe of the Ashawa glaciation, the upper Des Moines River held strategic position in one of the strangest drainage recoveries and reversals, during ice-cap retreat, that has ever been recorded. While melting of this Keewatin ice-cap, of the Last Glacial cycle, was going on. the Des Moines River played a curious part. It carried off the major volume of melt-waters for an interval of 300 years, until the ice had melted back to Blue Earth, Minnesota, on the drainage divide between the Des Moines and the Minnesota rivers