Definition: A tract of alluvium formed at the mouth of a river where the deposition ofsome of its load exceeds its rate of removal, crossed by the divergent channels (distributaries) of the river.
Definition: A desert biome is a terrestrial biome which loses more liquid water by evapotranspiration than is supplied by precipitation and includes communities adapted to these conditions.
Definition: A landform that extends above the surrounding terrain in a limited area. A mountain is generally steeper than a hill, but there is no universally accepted standard definition for the height of a mountain or a hill although a mountain usually has an identifiable summit and a local relief of more than 300m.
Definition: A landform that extends above the surrounding terrain in a limited area. A mountain is generally steeper than a hill, but there is no universally accepted standard definition for the height of a mountain or a hill although a mountain usually has an identifiable summit and a local relief of more than 300m.
Definition: A depression caused by erosion by water or ice. Low-lying land bordered by higher ground; especially elongate, relatively large gently sloping depressions of the Earth's surface, commonly situated between two mountains or between ranges of hills or mountains, and often containing a stream with an outlet.
Definition: An isolated hill with steep sides and a small flat top, smaller than mesas and plateaus. Buttes are formed by erosion when a cap of hard rock, usually of volcanic origin, covers a layer of softer rock that is easily worn away. This hard rock avoids erosion while the rock around it wears down.
Definition: An area of land of low topographic relief that historically supported grasses and herbs, with few trees, and having generally a mesic (moderate or temperate) climate. Dominated by tall grasses (contrast steppe).