Bed (Bottom) Topography

Bed topography represents the shape and features of the riverbed. The shape of a riverbed is largely determined by the relief of the terrain through which river crosses. Riverbed topography varies due to local controls imposed by boulder, log, and gravel bar obstructions. Increased flow, as during a flood or high rainfall season, can make permanent changes to the riverbed by displacing rocks and boulders or by deposition of alluvium. In a meandering river, the riverbed topography is modified by the development of point bars at the inner side of each bend because of the localized deposition and erosion processes.

The riverbed topography affects the flow characteristics of a river. The frictional effects related to the riverbed topography make the flow of water in a river cross-section nonuniform. The river water may exhibit strong turbulence caused in part by certain features of the river topography. Riverbed topography is considered as a primary factor in creating rapids. Variation in...