Build up

• Fill, as with silt
• Build up a slope
• One's learned in time to raise the surface level

WordNet Word definitions in WordNet
v. build up to a level by depositing sediment [ant: degrade ]

Wiktionary Word definitions in Wiktionary
vb. (context transitive geology English) to raise the level of a river bed by the deposition of sediment

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Aggrade \Ag*grade"\, v. t. [imp. & p. p. Aggraded ; p. pr. & vb. n. Aggrading .] (Phys. Geog.) To bring, or tend to bring, to a uniform grade, or slope, by addition of material; as, streams aggrade their beds by depositing sediment.