May 20, 2012

Building in the Lake Travis Floodplain

If you are considering building on Lake Travis and probably on many other lakes, there are some things you need to know. Lake Travis is west of uptown Austin, Texas nearby 45 minutes. everything in this article will be exact to Lake Travis, but it may furnish some things to think about for anyone building on any lake.

The first thing a buyer of Lake Travis waterfront asset needs to learn about is the floodplain. The full level of Lake Travis is 681 feet above sea level. The floodplain is at 722 feet. Why the huge difference? Lake Travis rises and falls depending on rain and on water use. Lake Travis is the main flood control lake of the Highland Lakes and it is managed by the Lower Colorado River Authority (Lcra). The Lcra has obligations to publish water downstream because of water contracts. At times without rain, the lake will drop. When we get too much rain, the Lcra holds it back in Lake Travis to minimize or forestall downstream flooding.

Ok, so the level of Lake Travis can change. What does that have to do with building on lakefront property? With the floodplain at 722 feet, the requirement for building is that the first occupied floor of a house needs to be at 723 feet or higher. So the first thing you need to know is the elevation of the lot - the whole lot - and the location of the floodplain if part of the lot is in it. Most lots on Lake Travis slope and the slope can be polite or it can be very steep. If the lot is low to begin with, you probably want to build as close to toe highest level of the lot as possible.

Some lots are obviously very much in the floodplain. Many of the houses will be built on stilts. Some leave the area under the house open. The constructor of other houses enclose large garages under much of the house with brick or stone.

Many of these houses will have many flights of stairs. Others will setup ramps. You may be wondering about an elevator instead of stairs or a ramp. My understanding is that this is just one more mechanical law that will be damaged when the water rises and an elevator would probably be pretty expensive to replace or repair.

Other things to think about that get more detailed are the septic system, the location of air conditioning compressor, a propane tank if you will have gas, the electrical service panel (breaker box) and water law tool if not on city or other incommunicable water. To minimize damage, these items should be elevated. Lake Travis has been above 700 feet three times and above 690 four times since 1990. As the lake has never been higher than 711 feet, placing these at 715 feet or higher would probably fine, but there would still be some risk.

Many of the available lots you will find with frontage on Lake Travis will not have collective water or sewer. Septic systems are quite common. There are two types you can install. If there is sufficient room, a gravity law can be used. These septic systems have next to nothing mechanically so they are less susceptible to damage by flood waters. Aerobic septic systems have many mechanical parts. Aerobic systems are commonly installed when there is less room for a large incommunicable septic drain field.

Here is the problem with a septic system: when the lake floods, the septic tank cannot function properly. If it is an aerobic system, the electricity will not be working and the tool will not work. If it is a gravity system, the tank won't be able to drain. In other words, when the lake floods and your law is under water, you can't count on using plumbing. This may be fine if you have a weekend house, but what about living there full time. When Lake Travis floods, the water commonly is back down in a week or so, but even being unable to use a house for a week may be a problem.

The Lcra has exact rules about locations of septic systems. The basic rule is that the bottom point of the septic drain field must be at the elevation of 691 feet or higher. In some cases a keeping tank might be lower than this, but the effluent would need to be pumped to a higher drain field and this would need a variance from the Lcra. So once again, you need to know the elevation of the entire lot in order to know if a septic law can even be installed.

Regarding water, if the lot you are looking at does not have some sort of municipal water supply, you will need a well or to draw water out of the lake. The Lcra does allow pumping water from Lake Travis for household use and landscaping, but you need a ageement with the Lcra to do that. You will also need a keeping tank and purification equipment. All of this should also be settled at a high sufficient elevation so none of the tool is within easy reach of floodwaters.

So getting back to building on a Lake Travis waterfront lot, there are things you need to know before going out and looking at lots. If you work with a Lake Travis Realtor®, he or she should be able to furnish advice in these areas.

building in the Lake Travis Floodplain

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