The map shows major lakes in Georgia. Surely there are additional lakes in Georgia, but these encompass the major lakes.
All these lakes are man-made via the construction of a dam. None of them are natural lakes.
By clicking a lake name, additional information will become available. Almost all of the data is made available from "other sources". This site is mainly a compilation of existing information from other sources, mainly the project owner. The owner of some of the projects, particularly the Corps of Engineers, make data readily available. Other owners do not make much of their data available, particularly Georgia Power and the TVA. And, of course, a lot of the "water availability" data and flood data come from the USGS and the National Weather Service (Southeast River Forecast Center), respectively ... who also make their data readily available.