aggraded valley floor

aggraded valley floor

[ə′grād·əd ′val·ē ′flȯr]
(geology)
The surface of a flat deposit of alluvium which is thicker than the stream channel's depth and is formed where a stream has aggraded its valley.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.