Why is it important to check groundwater levels before dewatering a large treatment tank?

Checking groundwater levels before dewatering a large treatment tank is critical to ensure the tank will not float. When a tank is emptied of its contents, the buoyant force exerted by the groundwater can exceed the weight of the tank itself, leading to a situation where the tank might lift or "float" out of the ground. This occurrence can result in damage to the tank and surrounding infrastructure as well as pose safety hazards. Ensuring that the groundwater levels are adequately assessed helps in determining the potential for flotation and allows for proper precautions to be taken, such as implementing a dewatering plan or bolstering the tank's foundations if necessary.

The other aspects of the question, such as electrical power, structural integrity, and tank capacity, while important in many contexts of tank management, do not directly relate to the specific concerns prompted by a change in the tank's water levels during dewatering.