Changes

[[file:M31F13.jpg|thumb|300px|{{figure number|6}}Summary diagram illustrating the major characteristics of the abandoned distributary deposits in the lower delta plain.<ref name=Colemanetal_1981 />]]

[[file:M31F13.jpg|thumb|300px|{{figure number|6}}Summary diagram illustrating the major characteristics of the abandoned distributary deposits in the lower delta plain.<ref name=Colemanetal_1981 />]]

The [[distributary channel]] is the natural flume which accommodates and directs a part of the water and sediment discharged from the parent river system to the receiving basin. In most deltas, the distributary channels are rather stable and do not display a tendency toward lateral migration, thereby preventing the formation of [[point-bar deposit|point-bar]] or [[meander-belt deposit]]s. In some deltas, for example, with high bedload streams or in those environmental settings where tidal range is high, migration of the distributary channel can take place, resulting in formation of deposits similar to channel deposits described in the [[delta plain, upper|upper delta plain]].

The [[distributary channel]] is the natural flume which accommodates and directs a part of the water and sediment discharged from the parent river system to the receiving basin. In most deltas, the distributary channels are rather stable and do not display a tendency toward [[lateral]] migration, thereby preventing the formation of [[point-bar deposit|point-bar]] or [[meander-belt deposit]]s. In some deltas, for example, with high bedload streams or in those environmental settings where tidal range is high, migration of the distributary channel can take place, resulting in formation of deposits similar to channel deposits described in the [[delta plain, upper|upper delta plain]].

Although little research has been conducted, the lack of channel migration in the lower delta plain is undoubtedly due to the fact that most river channels scour down through their distributary-mouth-bar deposits into underlying [[marine clay]]s. This scouring provides an entrenchment of the distributary channel with minimal tendencies for lateral migration. Active distributary channels vary considerably in size, some only a few meters wide and 1 to 2 m deep, and others of a large major river delta system with channels reaching 1 km in width and 30 m in depth. Depth within the channel decreases rapidly as the river-mouth bar is approached, and water depths over most distributary-mouth bars rarely exceed 3 m.

Although little research has been conducted, the lack of channel migration in the lower delta plain is undoubtedly due to the fact that most river channels scour down through their distributary-mouth-bar deposits into underlying [[marine clay]]s. This scouring provides an entrenchment of the distributary channel with minimal tendencies for lateral migration. Active distributary channels vary considerably in size, some only a few meters wide and 1 to 2 m deep, and others of a large major river delta system with channels reaching 1 km in width and 30 m in depth. Depth within the channel decreases rapidly as the river-mouth bar is approached, and water depths over most distributary-mouth bars rarely exceed 3 m.