The 30 -meter contour line designates the outer 

 margin of the deep basin, which is limited to the 

 eastern area, and forms only 9 percent of the total 

 area of the lake. The Deep Hole, bounded by the 

 40 -meter contour, comprises but 4. 5 percent. The 

 deeper portion of the western basin is indicated by 

 the 25 -meter contour with an area of approximately 

 593 square miles. The eastern area at this depth is 

 approximately 1, 013 square miles. 



The lake empties into the Niagara River dis- 

 charging 206, 000 cubic feet per second at mean 

 height (572.42 feet above the sea level). The dis- 

 charge increases at a rate of 22, 000 feet per second 

 with each rise of 1 foot. There is an average rainfall 

 of 34 inches in this region and an annual variation of 

 the lake level of approximately 1 foot, the maximum 

 being in June and the minimum in January (Uspensk: 

 1928). 



Table 1. --Area of Lake Erie at different depths 



