Tributary confluence bar (channel junction bar, eddy bar)
Formed at, and immediately downstream of, the mouth of tributaries. These delta-like features have an avalanche face. They generally comprise poorly sorted gravels and sands with complex and variable internal sedimentary structures. They represent a form of slackwater deposit (interbedded sands and mud) that is not elevated above the channel and is prone to reworking.
Typically form at high flood stage in reaches where a comparatively minor tributary enters the trunk channel. Flow separation and generation of secondary currents in the backwater zones promote sedimentation in sheltered areas under low flow velocity conditions.