Fill terraces: Fill terraces are the result of an existing valley being filled with alluvium. The valley may fill with alluvium for many different reasons including: an influx in bed load due to glaciation or change in stream power which causes the valley, that was down cut by either a stream or river, to be filled in with material (Easterbrook). The stream or river will continue to deposit material until an equilibrium is reached and it can transport the material rather than deposit it. This equilibrium may last for a very short period, such as, after glaciation, or for a very long time if the conditions do not change. The fill terrace is created when the conditions change again and either a stream or river starts to incise into the material that it deposited in the valley. Once this occurs benches composed completely of alluvium form on the sides of the valley. The upper most benches are the fill terraces. As it continues to cut down through the alluvium the fill terraces are left above the river channel (sometimes 100 m or more). The fill terrace is only the very highest terrace resulting from the depositional episode; if there are multiple terraces below the fill terrace, these are called "cut terraces".