Swale is a term used to refer to a low-lying area of land, especially one that is often wet or marshy. Other synonyms that can be used to refer to a swale are depression, hollow, dale, glen, or vale. A swale can also be called a trough, basin, or valley, depending on the context it is used. The word swale is often used in environmental science to describe a type of vegetated depression that is used for stormwater management and erosion control. In this context, it can also be referred to as a bioswale or a rain garden. Regardless of the term used to refer to it, a swale remains an essential feature in the natural landscape.