Lake Travis was created by the impounding of the Colorado River by the construction of Mansfield Dam in 1937- 41. It's main function is a flood control reservoir. That's the bad news - it's not a constant level lake. But, that's the good news, too. The fluctuation is what makes it so clean, and so rugged and so beautiful.
The lake is considered full at an elevation of 681' (above sea level). When you're looking at the lake, you can tell where 681' is - it's the top of the white band. But, it is often not "full". The highest its ever been level is 710' (December '91), and its lowest is 614' (August '51). That's a difference of 94 feet!
So, what this means, is that there will not be the manicured lawn right up to the shoreline, with the house set back nearby.
The lake is ~ 65 miles long. There are 270 miles of shoreline around the lake.