Archimedes‘ principle states that the upward buoyant force that is exerted on a body immersed in a fluid, whether fully or partially submerged, is equal to the weight of the fluid that the body displaces and acts in the upward direction at the center of mass of the displaced fluid. – Wikipedia
In relation to oil tanks and other objects that are placed over groundwater, the application of the Archimedes Principle regarding the Buoyant Force is very important. Engineers need to calculate how much force would be needed to cause the tanks to be lifted and displaced or damaged by water. Avoiding leaking storage tanks is very important. Displacement potential must be respected.
Most fuel storage tanks are affected by groundwater. Groundwater can cause oxidation to the metal tank, leading to erosion that will eventually leak and damage the environment. The Archimedes principle applied to Underground Storage Tanks are used to prevent a larger problem than the oxidation of tanks. What engineers are trying to prevent when implementing the principle is the displacement and destruction of the tank by rising groundwater. A displaced tank will move and collapse spilling all contents, which might require the need for spill containment products.
Knowing that all underground tanks are affected by the presence of groundwater is important. Engineers study water tables and actuarial data regarding rainfall predictions and the past history of floods etc. as they plan to install a new tank keeping the Archimedes Principle in mind.