<P> In geomorphology, drainage systems, also known as river systems, are the patterns formed by the streams, rivers, and lakes in a particular drainage basin . They are governed by the topography of the land, whether a particular region is dominated by hard or soft rocks, and the gradient of the land . Geomorphologists and hydrologists often view streams as being part of drainage basins . A drainage basin is the topographic region from which a stream receives runoff, throughflow, and groundwater flow . The number, size, and shape of the drainage basins found in an area vary and the larger the topographic map, the more information on the drainage basin is available . </P> <P> According to the configuration of the channels, drainage systems can fall into one of several categories known as drainage patterns . Drainage patterns depend on the topography and geology of the land . </P> <P> A drainage system is described as accordant if its pattern correlates to the structure and relief of the landscape over which it flows . </P> <P> Dendritic drainage systems (from Greek δενδρίτης, dendrites, "of or pertaining to a tree") are the most common form of drainage system . In a dendritic system, there are many contributing streams (analogous to the twigs of a tree), which are then joined together into the tributaries of the main river (the branches and the trunk of the tree, respectively). They develop where the river channel follows the slope of the terrain . Dendritic systems form in V - shaped valleys; as a result, the rock types must be impervious and non-porous . </P>

Differentiate between the drainage system of north india and that of south india