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. |