1. (Land) - Building up of
land surfaces by sedimentation or deposition of mineral matter. The depositional
process itself. The growth of a permafrost area.
2. (Streambed) - A
progressive buildup or raising of the channel bed and floodplain due to sediment
deposition. The geologic process by which streambeds are raised in elevation and
flood plains are formed. Aggradation indicates that stream discharge and/or
bed-load characteristics are changing. Opposite of degradation.
3. (Streambed) - The process of building up surfaces, such as stream-beds or floodplains, by the deposition of sediment and/or colluvium. http://220.127.116.11/streamwatch/glossary.htm