Why rivers, the lifeline of the nation, must flow

India is blessed with galore rivers that supply its colonisation with resources for irrigation, industry, home purposes, hydroelectricity, transportation, fishing, fertile onshore for agriculture, etc.

There are assorted ways of classifying Indian stream systems, specified arsenic based connected catchment size, root and predisposition to the sea. Broadly, they are classified into Himalayan rivers, which see the Indus, Ganga and Brahmaputra and their tributaries, and the Peninsular rivers based connected their origin. 

There are differences betwixt the 2 stream systems based connected their root of water, regime, travel etc. Himalayan rivers are perennial, fed by glaciers and monsoon, and have 2 maxima oregon highest travel periods – one during summertime owed to glacial melt and the 2nd during the southwest monsoon. They person comparatively larger basins and meandering courses arsenic they walk done soft sedimentary rocks. 

On the different hand, Peninsular rivers are mostly seasonal and person lone 1 maxima oregon highest travel during the monsoon, but for the Kaveri, which besides receives water from the northeast monsoon. These rivers person smaller basins and comparatively straighter courses owed to the beingness of hard peninsular rocks. 

Evolution of the Himalayan rivers

The improvement of the Himalayan rivers is explained by theories similar the Indo-Brahma/Siwalik River mentation of E.H. Pascoe and the Multiple River theory. The Indo-Brahma River mentation suggests that a ample stream erstwhile flowed from Assam to Punjab and perchance extended to Sind.

The mentation besides postulates that the present-day Indus and Brahmaputra rivers were portion of this ancient stream system and were separated later. The separation happened owed to geological events similar the Potwar Plateau upheaval successful the occidental Himalayas during the Pleistocene age, headward erosion by tributaries of the Indo-Brahma River, and the improvement of the Malda trough.

Many geological events person besides contributed to the existent drainage signifier of Peninsular India. The subsidence of the occidental flank of the Peninsula during the precocious Tertiary play and the tilting of the peninsular landmass towards the southeast resulted in the asymmetrical drainage of the Peninsular rivers chiefly towards the eastbound flank.

What theories connected the enactment of rivers say

Theories related to the enactment of rivers and the morphological features they make are portion of broader scenery improvement theories. One of the astir influential theories is W.M. Davis’s Cycle of Erosion (1889), which laid accent connected the relation of structure, process, and signifier (time) successful scenery evolution. Davis proposed that aft an archetypal accelerated uplift, the scenery goes done a implicit rhythm of improvement consisting of 3 stages: youth, maturity, and aged age.

However, Davis’s mentation was contested by W. Penck, who rejected the relation of clip and stated that geomorphic forms are shaped by the signifier and complaint of uplift successful narration to the complaint of degradation. Other notable theories see G.K. Gilbert’s Equilibrium Concept, L.C. King’s Uniform improvement of landforms successful varying biology conditions, J.T. Hack’s Dynamic Equilibrium Theory, and Morisawa’s Tectono-geomorphic model. 

Stages of stream landform development

True stableness of geological conditions is uncommon owed to factors similar complications of geological structure, diastrophic history, and climatic variations. However, successful lawsuit of the perfect fluvial (river) cycle, a wide series of processes and landform improvement is followed. It is important to enactment that the duration of antithetic stages is not uniform. 

Youth Stage  

In this stage, the enactment of V-shaped valleys, wherever vale deepening is much ascendant than vale widening, occurs. Fluvial erosion chiefly involves downcutting (valley deepening) and lateral erosion (valley widening). Both of these hap done solution/corrasion, abrasion, attrition, and hydraulic action.

Landforms similar canyons (such arsenic Grand Canyon successful Colorado) and gorges are immoderate of the features of this stage. Lakes and swamps whitethorn signifier successful areas adjacent section basal levels of erosion. The beingness of rapids and waterfalls is besides emblematic of this signifier owed to the presence of resistant rocks.

Maturity Stage 

In this stage, the stream attains a illustration of equilibrium, with vale widening becoming much ascendant than vale deepening, giving it a U-shape. Interstream disagreement becomes ridge-shaped. Depositional features similar alluvial fans (for illustration Kosi River Fan) and cones tin beryllium seen arsenic the stream enters the plains from the mountains.  Meanders and oxbow lakes (such arsenic Kanwar Lake) go salient successful this stage. 

Old Stage

Fewer tributaries are contiguous successful this stage. Very wide valleys with a gentle slope develop, and interstream areas are reduced successful height. The stream carries a finer load, and deposition becomes dominant. Lakes, swamps, and marshes are communal successful floodplain areas (such arsenic Ganga-Yamuna floodplains). Levee enactment and braided stream travel tin besides beryllium observed. Peneplanation and delta enactment (for illustration Sundarbans Delta) are communal features of this stage. 

However, fluvial cycles are seldom uninterrupted, arsenic assorted factors tin origin interruptions, including volcanic activity, climatic changes, and affirmative oregon antagonistic shifts successful the basal level of erosion. Rejuvenation of the fluvial rhythm tin besides instrumentality spot owed to factors similar subsidence of the oversea floor, glaciation, uplift of the landmass, oregon an summation successful h2o measurement of rivers.

Examples of rejuvenation see the improvement of nick points successful the stream illustration owed to tectonic activity, valley-in-valley topography, paired terraces, incised meanders, and uplifted peneplains. Such interruptions successful the fluvial rhythm pb to topographical discordance, wherever older landforms persist earlier the improvement of younger forms. 

Challenges and authorities initiatives 

Rivers of India look respective issues, similar pollution, flooding, h2o scarcity, and interstate disputes. Pollution is chiefly caused by the dumping of sewage, plastic, and municipal and concern waste. Flooding results from some earthy factors (such arsenic accrued rainfall owed to clime change) and quality activities (such arsenic deforestation, encroachment of floodplains, mediocre drainage, abrupt dam releases, and embankment failures).

Water scarcity chiefly occurs owed to vagaries of the monsoon, portion interstate disputes originate implicit water-sharing, specified arsenic successful stream basins similar Cauvery, Krishna, Godavari, and Narmada.

Various measures person been taken by the authorities to tackle these issues. To tackle contamination and cleanable rivers, schemes similar the National River Conservation Plan and Namami Ganga were launched. The Water (Prevention and Control of Pollution) Act, 1974 was besides enacted to modulate pollution. Programmes similar AMRUT and the Smart Cities Mission absorption connected improving sewerage infrastructure.

The Flood Management Programme was launched during the 10th Plan to code the issues of flood-affected states done measures similar drainage works and the operation of embankments. Government schemes similar Jal Shakti Abhiyan and MGNREGS (which see h2o conservation and rainwater harvesting structures) purpose to tackle h2o scarcity. The Inter-State River Water Disputes Act (1956) was enacted to resoluteness disputes implicit stream h2o sharing.

The National Waterways Act, 2016 was introduced to easiness the load connected roadworthy and obstruction transport by designating 111 waterways arsenic National Waterways. A National Perspective Plan for the interlinking of rivers was besides prepared by the Ministry of Irrigation successful 1980, though its implementation depends connected the statement of the acrophobic states.

Post Read Questions

How are Indian stream systems classified? What are the large differences betwixt Himalayan and Peninsular rivers?

What are the main theories related to the enactment of rivers and their morphological features?

What are the cardinal features of the youth, maturity and aged stages successful stream development?

What measures person been taken by the authorities to code contamination successful rivers?

What is the Inter-State River Water Disputes Act, and however does it resoluteness water-sharing conflicts?

How does the National Perspective Plan for the interlinking of rivers purpose to code h2o absorption issues successful India?

(Raj Shekhar is pursuing his Ph.D. successful Geography from Jawaharlal Nehru University.)

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