drainage pattern

(hydrology) The configuration of a natural or artificial drainage system; stream patterns reflect the topography and rock patterns of the area.

The pattern of a drainage network. This pattern is strongly influenced by geological structure. Anastomotic drainage shows a division of a river into several channels, and develops on nearly horizontal, coarse sediments. Annular, or radial drainage shows the major rivers radiating out from a centre with the tributaries arranged along a series of nested arcs. Annular drainage develops on domes, particularly where belts of resistant rock are separated by belts of weaker rock. Centripetal drainage shows a movement into a centre created by a crater or depression. Dendritic drainage shows a branching network similar to that of a tree, and is most commonly found on horizontally bedded or crystalline rocks where the geology is uniform. Parallel drainage develops in slopes of moderate angle. Rectangular drainage shows the tributaries running at right angles to the major river and occurs on rocks which have intersecting, rectangular joints and faults. Contorted drainage is a form of rectangular drainage on complex metamorphosed rocks. Trellised drainage resembles a trained fruit tree. It usually occurs on dipping or folded sedimentary or weakly metamorphosed rocks.