"Medina Lake covers about 5,575 acres, has a length of 18 miles, a maximum width of three miles, and 110 miles of shoreline." From this site - Lake Medina
Lake Travis is 63.75 miles long, and its maximum width is 4.5 miles. The lake covers 18,929 acres, and its capacity is 1,953,936 acre-feet. The lake is considered full at an elevation of 681.1 msl. At this elevation the lake contains 382,092,882,600 gallons of water. There are 270 miles of shoreline around the lake. It has a maximum depth of 210 and an average depth of 62 feet. From this site - Lake Travis
Big difference in capacity between the two lakes and Travis is the main source for water for many cities and communities here.
Central Texas lakes slide show
Those islands are usually under water, but you can now drive across to the end. That boat ramp in the foreground is also closed.