Upper Ganga Plain

The Upper Ganga Plain is a distinct physiographic sub-division of the Great Northern Plains of India. It represents a vast, low-relief aggradational plain formed by the depositional action of the Ganga River and its numerose Himalayan and Peninsular tributaries.

Geographical Extent and Boundaries

• Latitudinal and Longitudinal Extent: The plain lies approximately between 26° N to 30° N latitudes and 77° E to 82° E longitudes.
• Political Coverage: It encompasses the western and central parts of Uttar Pradesh, alongside the National Capital Territory (NCT) of Delhi and parts of Uttarakhand.
• Boundaries: It is bounded by the Shivalik Range to the north, the Yamuna River and the Delhi Ridge to the west (which forms the structural water divide separating it from the Indus-Punjab plains), the Bundelkhand and Vindhyan plateaus to the south, and the Middle Ganga Plain (marked roughly by the 100-cm annual rainfall isohyet) to the east.

Topographic Features and Slope

• Elevation: The elevation varies from approximately 300 meters above sea level in the north-west near the Shivalik foothills to about 100 meters in the east at the confluence zone of Allahabad (Prayagraj).
• Slope Gradient: The general slope of the plain is from north-west to south-east. The terrain exhibits a remarkably gentle gradient, sloping at an average of less than 25 centimeters per kilometer.
• Geological Origin: Structurally, it occupies the western part of the Himalayan foredeep basin, filled with thick layers of Pleistocene and Holocene alluvium. The depth of the alluvial deposits is greatest near the Shivalik margins and thins out progressively toward the southern Peninsular edge.

Morphological Zones and Micro-Geomorphology

The Upper Ganga Plain displays a classic succession of four-fold macro-morphological zones from north to south, punctuated by micro-relief features created by fluvial processes.

The Bhabar and Terai Belt

• Bhabar: This is a narrow, porous belt running parallel to the Shivalik foothills. It is composed of unassorted boulders, gravels, and coarse sediments brought down by fast-flowing piedmont streams. Rivers often sink and flow underground within this zone due to high porosity.
• Terai: Located immediately south of the Bhabar, this zone features the re-emergence of underground streams. It is characterized by damp, marshy conditions, alluvial clay soils, and historically dense jungle cover, which has now been largely cleared for intensive agriculture.

Bangar and Khadar Formations

• Bangar Uplands: This represents the older alluvium of the Pleistocene epoch that forms the higher structural terraces of the interfluves, lying well above the reach of annual floods.
• Khadar Lowlands: This consists of the younger, lighter-colored alluvium deposited along the active floodplains. Locally termed as Khola or Bet in specific pockets, it is regularly renewed during the monsoon seasons.

Micro-Relief Nomenclature

• Bhur: These are isolated, wind-blown sand ridges or low hillocks found accumulated in the dry tracts of the Bangar uplands, particularly prominent along the eastern banks of the Ganga and Ramganga rivers.
• Dhaya: These are broad, elevated river bluffs or structural terraces formed where older river courses have shifted away, leaving distinct cliff-like banks.
• Kankar: Calcareous nodules composed of calcium carbonate precipitates that accumulate within the sub-soil layers of the older Bangar tracts due to capillary action.

Regional Divisions and Interfluves

The Upper Ganga Plain is traditionally divided into three distinct physiographic and socio-cultural sub-regions based on drainage basins and micro-climatic variations.

Rohilkhand Plain

• Location: Occupies the north-western section of Uttar Pradesh, lying east of the Ganga River and stretching up to the Avadh Plain.
• Drainage: Mainly drained by the Ramganga, Sharda, and Gomti rivers.
• Characteristics: Features a prominent transition from the Terai swamp margin into rich Bangar uplands.

Ganga-Yamuna Doab

• Location: The classic interfluve lying between the parallel courses of the Yamuna River in the west and the Ganga River in the east.
• Sub-divisions: It is divided into the Upper Doab (Meerut region), Middle Doab (Agra-Aligarh tract), and Lower Doab (Kanpur-Fatehpur region).
• Characteristics: Formed of deep, highly productive alluvium, it constitutes the agricultural backbone of western Uttar Pradesh.

Avadh (Oudh) Plain

• Location: Occupies the central and eastern portion of the Upper Ganga Plain.
• Drainage: Dominated by the Ghaghara, Sarda, and Gomti river systems.
• Characteristics: It is a low-lying, flat terrain that forms a transitional zone graduating into the Middle Ganga Plain.

Hydrological Framework and Soil Profiles

Drainage System

• Perennial Rivers: The Ganga and Yamuna are the major antecedent rivers originating from the Himalayan glaciers (Gangotri and Yamunotri) that enter the plain at Haridwar and Tajewala respectively.
• Himalayan Tributaries: The Ramganga, Ghaghara, and Sharda enter from the north, carrying high sediment loads.
• Peninsular Confluences: The Chambal, Sind, Betwa, and Ken rivers drain northward from the Malwa and Vindhyan plateaus, emptying into the Yamuna before its final synthesis with the Ganga at the Prayagraj Sangam.

Soil Characteristics and Environmental Degradation

• Soil Classification: The regional soils belong to the Alluvial category, typed structurally as Inceptisols and Alfisols. They are chemically rich in potash and lime but poor in nitrogen, phosphorus, and organic carbon.
• Reh and Kallar: In the arid and semi-arid tracts of the western doab, prolonged and unscientific canal irrigation has induced capillary action. This draws up dissolved salts to the surface, creating white, infertile alkaline efflorescences known locally as Reh, Kallar, or Usar.

Climate, Ecological Dynamics, and Human Interface

Climate Regime

• Classification: It experiences a Humid Subtropical climate with dry winters (Cwg under the Köppen climate classification).
• Precipitation Isohyets: Rainfall varies along an east-to-west declining gradient. The eastern border receives around 1000 mm annually, which drops to less than 700 mm near Delhi and the dry Aravalli margins.
• The Loo Wind: During May and June, the plain is subject to the Loo, which are intense, dust-laden, hyper-thermic westerly winds originating from the Thar Desert.

Agro-Economic Framework

• The Green Revolution Frontier: Alongside Punjab and Haryana, the Upper Ganga Plain (particularly the Western Doab) was the core beneficiary of the Green Revolution, adopting high-yielding varieties of seeds, chemical fertilizers, and mechanized farming.
• Cropping Pattern: The regional agricultural economy relies on a dual intensive system: Sugarcane and Rice during the Kharif season, and Wheat as the primary Rabi crop.
• Irrigation Infrastructure: The region is anchored by old, historically significant gravity canal networks, including the Upper Ganga Canal system, Lower Ganga Canal system, and the Eastern Yamuna Canal.

Key Facts and Trivia for UPSC Civil Services Examination

Regional Hydrographic Divide

The Delhi Ridge, which forms the northernmost extension of the ancient Aravalli Mountain Range, serves as the ultimate hydrographic divide of Northern India. It strictly isolates the Indus River drainage basin to the west from the Ganga River basin to the east.

The Asymmetry of Alluvial Filling

Geophysical surveys indicate that the floor of the Ganga foredeep basin is asymmetrical. The alluvial thickness increases systematically from south to north, hitting its deepest point right along the structural fault lines known as the Himalayan Frontal Thrust (HFT).

The Ancient Fluvial Track of Ramganga

Geomorphological mapping of palaeo-channels reveals that the Ramganga River has consistently shifted its course eastward over centuries, leaving behind wide, swampy abandoned channels that now form local fishing and wetland grounds in Rohilkhand.

The Bhur Formations of Ramganga

The sand ridges known as Bhur are distinctive to the Upper Ganga Plain. They were created during the dry phases of the Holocene epoch when strong southwest monsoon winds blew sand out of the dry river beds and piled it onto the adjoining older alluvium banks.