Drainage pattern and their significance

About the types of drainage present in the world wide and their significance.

1. Drainage Pattern and Their Significance Guided By Dr. Govindaraju Associate Professor Department of Applied Geology Submitted by Avinash B R II sem Geo-Informatics

2. Drainage Natural or artificial action of draining something or removal of surface or subsurface water remove from an area. The typical shape of a river course as it completes its erosional cycle is referred to as the Drainage Pattern of a stream. The drainage systems mainly depend upon the geological structure of the region and the resistance of the erosion capacity of the rock to erosion.

3. Drainage patterns are controlled by following factors: 1) Initial slope. 2) Lithology and lithological variation. 3) Structures. 4) Geologic and geomorphic history of the area. 5) Climate and rainfall of the area

4. Outlined Characteristics to Classify Degree of integration This element pertains to the degree of unity.it is an inductive of uniformity of various characters and the presence of modifying factors. Density The drainage density is already described is inductive of degree of erodibility slope on which erosion occurs and special climatic conditions.

5. Cont.….. Degree of Uniformity It is relatively homogeneity of pattern over an area.it indicates the boundaries between the area of different characteristics and uniformity of erosional history and the behaviour of the material of erosion. Orientation It refers to direction and indicates the control and effects due to the presence of geological factors like structural features and tectonic movements etc.

6. CONT…. Degree of control It is the most important feature in geological interpretation. The streams are shaped by the tectonic features like folding, faulting, fracturing etc. The tectonism products anomalies directional changes and adjustment which are useful in tectonic analysis of a terrain. Angularity It is abruptness of directional change furnished by the component streams of a drainage pattern. These serve as guides for revealing the hidden features like fractures, faults, shear zones and other features including underground structures.

7. CONT…. Angle of Junction Normally we find an acute angle in the upstream direction between stream and its tributary. It is a function of the channel slopes of two streams.

8. Consequent Are streams whose course is a direct consequence of the original slope of the surface upon which it developed, i.e., streams that follow slope of the land over which they originally formed Godavari, Krishna and Kaveri, descending from the Western Ghats and flowing into the Bay of Bengal, are some of the consequent rivers of Peninsular India.

9. Sub-sequent stream A stream that has developed on a weak substructure, such as a clay vale or in regional joint or fault pattern, at right angles to streams consequent to the dip of the slope.  The Chambal, Sind, Ken, Betwa, Tons and Son meet the Yamuna and the Ganga at right angles.

10. Obsequent stream A stream that flows in the opposite direction to a consequent stream, often against the direction of dip.

11. Inconsequent drainage Which is unrelated to the structure of the rocks over which the rivers flow. The show no relationship with the present structure and relief and cut right through the line of highest elevations.

12. Antecedent Drainage The river which is follow the path or course of the mountain without any modification in the topology. Drainage system where streams have maintained their valleys across tectonic mountains and across them in deep gorges are said to be antecedent because the river is older than or Antecedent to the deformation responsible for the present structure and relief. These drainages mostly found in regions of recent mountain movements.

13. Superimposed Drainage A stream formed on one surface and structure has science cut down through unconformity to flow over older rocks, which have structure discordant with that above the unconformity. Such a stream is then said to be superimposed on older rocks.

14. GEOMETRIC CLASSIFICATION Dendritic Pattern - This is the most common pattern and is characterised by tree like or fern like, irregular branching, haphazard orientation and irregular spacing of the tributaries Trellis Pattern - Trellised drainage patterns are formed by the network of tributaries and master consequent streams which follow the regional slope and are well adjusted to the geological structures.

15. Rectangular Pattern - In this pattern main stream and its tributaries display right angled bands. Streams are flowing in two directions at right angle each other. Parallel Pattern – A parallel drainage pattern consist of tributaries that flow nearly parallel to one another. Angulate Pattern - In this type the streams are developed equally in two directions, but streams meet at an acute angle rather than at right angle. Radial Pattern - This pattern develops from a central elevated tract such as volcano, dome or doubly plunging anticlines Inward Radial Pattern - is defined as the stream will diverge at one point or common point by the circular network channels. Outward Radial Pattern – Is defined as the stream will converge at common point where the central region is depression or dome like structure is present. Centripetal Pattern - This pattern is characterised by stream lines converging into a central depression. Found on sinkhole, craters and other basin like depressions.

16. Annular Pattern - Such pattern may be found around maturely dissected domes which have alternating bands of hard and soft rocks encircling them. Barbed Pattern - A drainage in which a stream suddenly bends back on itself and flows in an almost reverse direction often due to glacial blocking, suspended material river capture or local tectonic movement. Contorted Pattern - Tributaries are parallel but hng opposite flow direction than the main stream. Asymmetric Pattern – The pattern of the streams has more unequally tributaries are formed, most commonly observed in mountain region.

17. Yazoo Pattern - In hydrological or geological terms, a Yazoo stream is a tributary stream that lies within a single floodplain with a larger river and runs parallel to the river for a long distance and eventually joins it downstream. Reticular Pattern – The drainage pattern exhibits network or netlike structure of stream channels. Phantom Pattern – It is drainage pattern of seepage ways and looks cobweb like drainage. Illusory Pattern – It is nearly like phantom drainage expect that this is due to artificial drainage. soils are drained tiles is visible due to tonal contrast.

18. Complex and Compound Patterns – The group of drainage patterns dissimilar patterns which reflect different structural controls in adjoining areas. Deranged Pattern – this drainage knows as erratic, hap-hazard and disordered pattern, found in the glacial region and is very irregular. Pinnate Pattern - This pattern is characterised by long main stream and closely spaced short tributaries. It looks like feathers. Pectinate Pattern - Parallel gullies with pear shaped head water basins.

19. Kettle Hole Pattern – A kettle hole is formed by blocks of ice that are separated from the main glacier - perhaps the ice front stagnated or retreated or perhaps ice blocks were washed out from the glacier during a glacier flood. Swallow Hole - The swallow hole has been formed as the result of chemical weathering along a joint in the limestone bedding plane. Thermokarst - Thermokarst is a land surface characterised by very irregular surfaces of marshy hollows and small hummocks formed as ice-rich permafrost thaws. Elongate Bay Pattern – this drainage pattern is usually found in the coastal plains and deltas and is constituted of large elliptical and parallel depressions.

20. Anastomotic pattern - The anastomotic drainage pattern is characteristic of flood-plain drainage. Pincer like Pattern - Tributaries of 4th order and 3rd order show pincer like curved form. Develop on hard igneous rocks partly fracture controlled. Lacunate – The lakes are spaced at random and the individual tributaries connecting them may be dendritic drainage.

21. Significance: - If proper drainage is not existing in the land use area than flood can occurring capabilities will increase. Water can't store easily and places where rainfall is not adequate at their places water can't supply and canals, dam, stream, river, ponds, to ocean water level will decreases and ground water potential also decreases. Most of ground water is destroyed or waste due to improper drainage in the city and sometimes water logging occurs in monsoon and water remains logged and pollution of water will increase, and decreases will occur, and it's directly affects at national economical levels.

22. The drainage pattern and their flowing nature can encourage or increase the water storing capacity and water harvesting in the adjacent areas. The drainage pattern which helps to the green revolution due to the bunds created to the drainage pattern. These drainage pattern help the drainage which mainly increases the ground water potentiality. There are several concerns about the sustainability of irrigation and drainage projects, and there are water quality problems related to the disposal of drainage water. There have been instances where saline or high nutrient drainage water has damaged aquatic ecosystems.

23. Conclusion

24. Thank You