There are 304 million natural lakes on continents and these natural lakes cover more than 2.8% of the land surface, not including temporary water bodies and wetlands. Impounded waters cover another 0.22% of the land area and the number of small impoundments is growing rapidly as human water needs increase. Although the largest, often deepest, lakes of the world are best known and understood, the area of lakes on continental surfaces is largely dominated by small water bodies. The amount of land surface covered by lakes depends upon regional hypsometry, or the form, undulation, and tilt of the land surface. Small lakes cover a range of depths; however, large lakes are very rarely shallow. Many past analyses have both underestimated the area of the world covered by lakes and the disproportionate role of small water bodies in aquatic environments.