<P> The lake's average surface elevation is 600 feet (183 m) above sea level . Until approximately 1887 the natural hydraulic conveyance through the St. Marys River rapids determined outflow from Lake Superior . By 1921 development in support of transportation and hydroelectric power resulted in gates, locks, power canals and other control structures completely spanning St. Marys rapids . The regulating structure is known as the Compensating Works and is operated according to a regulation plan known as Plan 1977 - A. Water levels, including diversions of water from the Hudson Bay watershed, are regulated by the International Lake Superior Board of Control which was established in 1914 by the International Joint Commission . </P> <P> Lake Superior's water level was at a new record low in September 2007, slightly less than the previous record low in 1926 . However, the water levels returned within a few days . </P> <P> Historic high water The lake's water level fluctuates from month to month, with the highest lake levels in October and November . The normal high - water mark is 1.17 feet (0.36 m) above datum (601.1 ft or 183.2 m). In the summer of 1985, Lake Superior reached its highest recorded level at 2.33 feet (0.71 m) above datum . The winter of 1986 set new high - water records through the winter and spring months (January to June), ranging from 1.33 feet (0.41 m) to 1.833 feet (0.559 m) above Chart Datum . </P> <P> Historic low water The lake's lowest levels occur in March and April . The normal low - water mark is 0.33 feet (0.10 m) below datum (601.1 ft or 183.2 m). In the winter of 1926 Lake Superior reached its lowest recorded level at 1.58 feet (0.48 m) below datum . Additionally, the entire first half of the year (January to June) included record low months . The low water was a continuation of the dropping lake levels from the previous year, 1925, which set low - water records for October through December . During the nine - month period October 1925 to June 1926 water levels ranged from 1.58 feet (0.48 m) to 0.33 feet (0.10 m) below Chart Datum . In the summer of 2007 monthly historic lows were set; August at 0.66 feet (0.20 m), September at 0.58 feet (0.18 m). </P>

There is enough water in lake superior to cover this much land