(a) Effluent and influent river:
In case of effluent rivers, the regional water-table lies near the earth’s surface, as a result the river or stream is fed; whereas in case of influent rivers, the water-table is located at a great depth, a part of runoff is icheduled to percolat downwards.
Rivers existing before the surface relief was impressed upon the area.
The flow of the river occurs as a consequence to the existing surface relief.
The river which joins the consequent river arising later as erosion proceeds.
(iv) In sequent:
It displays no reason for its particular course, such as that upon homogeneous terrain.
Here the river drains in the opposite direction to the original consequent-river.
It drains in the same direction as the original consequent, but at a lower topographical level.
At some places, old rocks may be covered under a sheet of new deposits. Any river developed on such an area will follow the surface relief of the overlying cover and will not have any relation with the older rocks lying below. Gradual erosion removes the overlying cover and the river flows on the older rocks below. Here, the river is said to be super-imposed on the older rocks below.
The joining of the tributaries with the master stream produces a pattern termed drainage pattern. The common drainage patterns are:
This is characterised irregular branching of tributary streams in a similar pattern as that of a tree’s branches.
(ii) Parallel pattern:
Develops on steep slopes where the tributaries and the master stream flow parallel to each other.
(iii) Trellis pattern:
It develops in a topography created on a folded structure of synclines and anticlines, faults or joints etc.
(iv) Radial pattern:
It consists of drainage lines radiating from a central part as on a dome.