The sketch shows a reservoir that supplies water to a farm. It is made of wood and is reinforced with metal hoops. Why is it elevated? The reservoir is elevated so as to produce suitable water pressure in the faucets that it serves. It is elevated to keep it away from alien invaders. It is elevated to keep it away from bears and moose. If the reservoir was closer to the Earth's surface, the pressure inside would be too high to hold the water in