Types of Streams
On the basis of development and origin, the streams have been classified into four groups: (i) consequent streams, (ii) subsequent streams, (iii) antecedent streams, and (iv) superposed streams.
(1). Consequent Streams:
Consequent Streams are those which follow the slope of the initial land surface. The course the consequent streams is the direct consequence of the original slope of the surface upon which the stream is flowing. For example, streams that follow slope of the land over which they originally formed.
(2). Subsequent Streams:
Subsequent stream is the type of streams which are tributary streams that develop on the sloping sides of a stream valley. Subsequent streams generally take their course along the weak and easily erodible zones, such as rock boundaries, fault zone, joints, etc. These weak zones are discovered and eroded after the development of the consequent streams.
(3). Obsequent Streams:
They are also called Antecedent streams. Antecedent streams are those which are able to maintain their original course across the area of uplift.
(4). Superimposed Streams:
Geologic events may strongly control the course of a stream. Streams flowing in a dendrite pattern on horizontal bedded younger formation may erode through it to expose the underlying, strongly folded and faulted older rocks of varying hardness. Over the older rocks the stream course will not easily adjust to form a wholly new drainage pattern appropriate to the structure of rocks. Such streams are called “Superimposed Streams”. Superimposed streams do not show any relation to the structure of the underlying rocks.