Spongy ground is a type of wetland that is characterized by its soft, spongy soil. It is made up of three main types of wetlands: bogs, swamps, and fens. Bogs are acidic wetlands that are fed by rainwater and have very little drainage. Swamps are wetlands that are fed by both rainwater and groundwater and have slow-moving water. Fens are wetlands that are fed by groundwater and have alkaline soils. All three types of spongy ground are home to a variety of plants and animals.