Considerations

• A properly built levee takes a lot of space. Its sheer mass keeps it from moving. Long, gentle side slopes increase stability and provide for easier maintenance. A typical levee 3 feet high should be 21 feet wide. If the inner edge is 4 feet from the building, its outer edge will be 25 feet from the building.
• Where the property line is too close to allow an adequate levee, a floodwall or other floodproofing technique can be used in combination with a partial levee to provide a complete barrier system.
• For a given height of flood protection, a permanent earthen levee is about half the cost of a floodwall and slightly more than a commercial water-inflatable dam.
• It is easier to increase your flood protection level with a levee than with other permanent systems. When built with a broad, well-compacted base, levees can be topped with sandbags or water-inflated dams.
• To keep the permanent levee at a low or variable height, you may choose to build the system to protect against frequent, low-level floods, but design the base so the levee safely can be topped with temporary barriers for the less frequent, higher floods.
• If the depth of flood risk increases in the future, a well-founded levee can be topped with a permanent floodwall or additional earthen material.
• Neighbors often view levees as aggravating their own flood situations. Protecting the area right around a building may be less objectionable than excluding water from your entire lot.

Things to Remember

• Levees must be built to withstand the forces of standing water and flowing water. The potential effects of water currents should be analyzed by an engineer.

• Levees may require underground extensions to prevent seepage through the soil, depending on soil type, water depth and flood duration.

• You must provide drainage for rain that falls inside the levee system when it's NOT flooding and when it IS flooding.

• It's very hard to add drains once the levee is built, so make sure the number, size and locations are right before you pile on the dirt.

• A pump is needed inside the protected area. Water can seep under or through the levee, and rain will fall on the inside. You have to pump it out during a flood. Placing the levee closer to the building may reduce your dependence on pumps.

• Levees have natural enemies: burrowing creatures and tree roots. Check your levee each year for signs of tunneling.

• Check with the local building or permit office to see if a permit is required. Some communities review plans to be sure the levee will not interfere with drainage and will not diminish flood storage capacity in violation of local law.

• Avoid damaging underground gas, water and electrical lines or your sewer line during construction. In Louisiana, call 811 (LA One Call) to get help with locating these lines.

• When water goes over the top or breaks a levee, the protected area may fill with water rapidly. Rushing water and debris may come crashing into the building.

• Plan for your safety. Decide in advance when you will abandon a flood fight and save your life.