D numerical models

Flows in curved and braided channels and near in-stream structures usually exhibit complex three-dimensional features that significantly affect sediment transport and morphological evolution processes. Realistically simulating these complex near-field phenomena must rely on 3-D models rather than 1-D or 2-D models. Introduced in this chapter are 3-D modeling approaches for open-channel flows, sediment transport in general situations, local scour near in-stream structures, and headcut migration.