Calaveras Lake and Victor Braunig Lake are artificial lakes that provide cooling water for nearby power plants. The lakes are also popular fishing and boating destinations. Two of the power plants can be seen in the images, in the crooks of the two larger lakes (Calaveras is on the right).
By contrast, Mitchell Lake, west of Braunig Lake, is a natural lake. The shallow lake is on a migratory bird route and is used by over 300 species as a resting point. Because it is shallower than Braunig Lake and Calaveras Lake (average depth less than 8 feet), Mitchell Lake appears slightly blue in some images.
You’ll also notice a major change just west of Mitchell Lake between the 2002 and 2013 images. The smattering of white along the western edge of the 2013 image is Toyota Motor Manufacturing Texas, a manufacturing plant for Toyota pickup trucks. The plant began operations in 2006.