These bays have an elliptical shape and generally a northwest to southeast orientation. They are found primarily in Georgia and the Carolinas, but range from Florida to Delaware. As many as 300 Carolina bays exist on the Savannah River Site.
Water levels are normally lowest in autumn and highest in early spring.
Some Carolina bays are wet all year, while others fill with water, then dry up, depending on the season. The amount of time a typical bay holds water can vary greatly from year to year depending upon rainfall. For example, during a 13-year period, Rainbow Bay on the Savannah River Site held water only five days one year and about 280 days another year. Although many Carolina bays are temporary ponds that hold water only part of the year, these wetlands host a variety of wildlife, providing valuable habitat for such animals as frogs, salamanders, turtles, snakes and alligators. Many birds, such as herons, egrets and migratory waterfowl, live in Carolina bays.