I had a call a few weeks ago from a guy who found a Lake Travis waterfront lot online for $160,000.  He was pretty excited about this as it is just about the least expensive waterfront lot you will ever see on Lake Travis.  When he gave me the address, I immediately know why.  The lot was deep in the Lake Travis floodplain.

To build in the Lake Travis floodplain, you need to build in such a way that the first floor of the structure that will contain interior living space will be one foot above the floodplain and the floodplain is 722 feet above sea level.  Knowing that the full level of Lake Travis is at 681 feet, that is quite a way above the water when the lake is full.  So what you need to do is something like this:

Lake Travis homes being built in the floodplain.

Just behind the small outbuilding you can see ramps leading up to the first floor of the house in the foreground.

other view of Lake Travis home being built in the floodplain

This is the view from one side of the houses.  The one in the background is obviously in the initial stages of being built.

So what you have with the first house is a nice looking place above where potential flood waters will be.  Rather than stairs, there is a ramp traversing to the front door.  The view from the deck you can see looks right out at the main body of Lake Travis.  One problem is that when the water covers the ground, the septic system will not be usable.  The other problem is access during a flood will be by boat.

What this clearly shows though is that building in the floodplain is very doable.  You just need to understand that if this is a year round house and the lake comes up, you will need to find a hotel or a friend to hang out with for a while.