Even if you have insurance to cover repairs, bringing a damaged UST back up to code can be a lengthy process, particularly if the flooding is widespread and qualified UST contractors are in high demand. Furthermore, loss of product can lead to environmental pollution and the attendant remediation obligations and costs.
If You are in a Flood-Prone Area
In low-lying areas subject to flooding, UST systems should be designed and constructed in light of the flooding risk. For example:
- Increase the burial depth and/or amount of pavement above the UST. The extra weight of the backfill and pavement may be enough to keep the tank from floating. Burial depth should not exceed the manufacturer’s recommendation.
- Anchor the UST to counteract the buoyancy force exerted by saturated soil during a flood to prevent flotation. The guidance recommends that deadmen anchors be placed outside the tank diameter along the sides of the UST, with hold-down straps attached. A concrete collar can also be used for additional weight.
- Use hold-down straps to securely attach the tank to a bottom hold-down pad.
- Equip fuel lines below the flood elevation level with automatic shut-off valves. This will help prevent loss of fuel in case of line breaks or disconnects from the UST.
- Add an extension to the vent pipe if it appears the tank may be submerged in deep floodwaters. If water enters the vent pipe, it will settle at the bottom of the tank, pushing product out.
What to Do Before a Flood
If flooding is a near-term possibility, take the following steps:
- Turn off all electricity to the UST system, including power to dispensers, pumps, turbines, automatic tank gauging (ATG) consoles, lighting, and any other system components.
- Take product inventory and water level reading of all USTs to help account for possible product loss.
- Fill the tank to weigh it down so it will not float out of the ground.
- Secure all openings on top of the tank and make sure fill caps are in good condition and fastened securely in place and locked. If fill caps are not tightened, tanks will fill with water and release product. Empty or near-empty tanks may float up, destroying overlying concrete/asphalt and distribution lines, which can also release product.
- Make sure the seals on spill bucket plungers are operational so water cannot enter the tank.
- Close the shear valve on pressurized piping to prevent releases from product dispenser lines.
- Temporarily cap the vent pipes to prevent water from entering the tank and displacing product.
- Place a Dumpster, sand bags, or large containers full of sand or rock over the tank to reduce the chance of a tank floating out of the ground.