Many lakes, such as the Great Lakes, were formed by glaciers--large, thick sheets of ice that slowly moved across the land long ago. Glaciers scooped out holes in the land. These areas, called “basins,” filled with water when the glaciers melted.
There are many other ways in which nature creates lake basins. But people can also create basins that fill with water. These are called “reservoirs,” which is a French-sounding way of saying “man-made lakes.”
Some lakes are created by people. Other lakes have been created naturally by glaciers.
Photo: USDA NRCS