Mahanadi

The Mahanadi is one of the major rivers of peninsular India, flowing through the states of Chhattisgarh and Odisha before emptying into the Bay of Bengal. The river holds immense geographical, historical, and economic importance, sustaining millions of people through irrigation, drinking water, and hydroelectric power. Known in Sanskrit as “The Great River”, the Mahanadi has been a cradle of ancient civilisation and remains vital to the socio-economic development of eastern India.

Origin and Course

The Mahanadi River originates from the Sihawa Hills near Pharsiya village in the Dhamtari district of Chhattisgarh, at an elevation of about 442 metres above sea level. It flows for approximately 851 kilometres, of which about 357 kilometres lie in Chhattisgarh and 494 kilometres in Odisha.
The river’s course can be divided into three major segments:

1. Upper Course (Chhattisgarh Plateau): The Mahanadi flows eastwards through narrow valleys and forests of the Raipur and Sambalpur regions. Here, it receives tributaries such as Seonath, Hasdeo, and Mand.
2. Middle Course (Odisha Plains): Emerging from the highlands, the river widens into an extensive deltaic plain in Cuttack and Puri districts, where it branches into distributaries.
3. Lower Course (Delta and Estuary): Finally, it forms a fertile delta, shared with rivers like Brahmani and Baitarani, before draining into the Bay of Bengal near Paradeep.

The total catchment area of the Mahanadi is about 141,600 square kilometres, covering parts of Chhattisgarh, Odisha, Jharkhand, Maharashtra, and Madhya Pradesh.

Major Tributaries

The Mahanadi system includes numerous tributaries and distributaries:

• Left-bank tributaries: Seonath, Hasdeo, Mand, Ib.
• Right-bank tributaries: Ong, Tel, Jonk.

Among these, the Seonath and Hasdeo rivers are the most significant in Chhattisgarh, while the Tel and Ong rivers contribute major flows from western Odisha.

Physiographic and Climatic Characteristics

The river flows through diverse landscapes—from forested highlands and rolling plateaus to fertile alluvial plains. The Mahanadi basin receives heavy monsoonal rainfall, averaging about 1,400 mm annually, with over 80% of its discharge occurring between June and September.
Because of this, the river is sometimes referred to as the “River of Sorrow” for Odisha, as seasonal floods historically caused immense damage to life and property in the delta region. However, modern irrigation and flood-control projects have mitigated these effects considerably.

Major Projects and Dams

The Mahanadi has been extensively harnessed for irrigation, hydroelectricity, and flood control through several large-scale projects.

• Hirakud Dam:
  • Located near Sambalpur, Odisha, it was completed in 1957 and is one of the longest earthen dams in the world, spanning about 4.8 kilometres.
  • The dam creates the Hirakud Reservoir, covering 746 square kilometres.
  • It provides irrigation to about 7.5 lakh hectares of land and generates 347 MW of hydroelectric power.
  • It also controls floods in the lower Mahanadi delta, transforming the region’s agriculture and economy.
• Ravishankar Sagar (Gangrel Dam):
  • Built on the Mahanadi near Dhamtari, Chhattisgarh, it serves irrigation, drinking water, and power generation needs.
• Hasdeo Bango Dam:
  • Constructed on the Hasdeo River, a major tributary of Mahanadi, it supports irrigation and electricity generation in Chhattisgarh.

These projects form part of a network of multipurpose schemes contributing to the industrial and agricultural development of central and eastern India.

Irrigation and Agricultural Importance

The Mahanadi basin is one of India’s most agriculturally productive regions. The fertile alluvial soils of its delta support extensive cultivation of:

• Rice (the staple crop)
• Pulses
• Oilseeds
• Sugarcane
• Vegetables and fruits

The irrigation systems built along the river, especially from the Hirakud and Mahanadi Delta projects, have made Odisha and Chhattisgarh major contributors to India’s food production.

Hydroelectric and Industrial Significance

The river supports several hydroelectric power plants, including those at Hirakud, Champa, and Korba. The energy generated aids industrial centres such as:

• Bhilai Steel Plant (Chhattisgarh)
• NALCO Aluminium Plant (Angul, Odisha)
• Thermal power stations in Sambalpur and Talcher

The Mahanadi basin is also rich in coal, bauxite, and iron ore, making it a key industrial corridor in eastern India.

Environmental and Ecological Aspects

The Mahanadi basin hosts diverse flora and fauna. The river’s upper catchment is forested, home to teak, sal, and bamboo, and supports wildlife including elephants, leopards, and migratory birds.
However, rapid industrialisation and deforestation have caused ecological challenges:

• Pollution from mining and industrial effluents.
• Siltation of reservoirs and riverbeds.
• Altered flow patterns due to dams and barrages.
• Threats to aquatic life, including declining fish populations.

Conservation efforts are underway, focusing on sustainable water management, pollution control, and ecosystem restoration.

Water Disputes

The Mahanadi water dispute between Odisha and Chhattisgarh has been a major inter-state issue. Odisha alleges that upstream dams and barrages in Chhattisgarh have reduced water flow into its territory, affecting agriculture and ecosystems in the delta.
In response, the Central Government established the Mahanadi Water Disputes Tribunal in 2018 to adjudicate the issue under the Inter-State River Water Disputes Act (1956). The tribunal’s deliberations continue, with both states seeking equitable sharing and cooperative water management.

Historical and Cultural Importance

The Mahanadi has been central to the historical and cultural life of eastern India. Ancient settlements and trade routes developed along its banks, and archaeological remains from sites such as Sirpur and Sambalpur testify to its long habitation and cultural continuity.
In mythology, the river is associated with various Hindu traditions and is revered as sacred. Pilgrims visit the confluence of the Mahanadi and its tributaries for rituals and festivals, especially during Makar Sankranti and Magha Mela.
The city of Cuttack, one of Odisha’s oldest urban centres, and the state capital Bhubaneswar, both owe much of their development to the fertile Mahanadi delta.

Delta and Estuary

The Mahanadi Delta, one of the largest in India, spans across Cuttack, Puri, and Jagatsinghpur districts. It merges with the Brahmani and Baitarani rivers, forming a combined deltaic region known as the Mahanadi–Brahmani–Baitarani Delta, renowned for its fertility and biodiversity.
The delta also includes parts of the Chilika Lake, Asia’s largest brackish water lagoon, and the Bhitarkanika Mangrove Forests, a UNESCO-recognised biodiversity hotspot that shelters endangered species like the saltwater crocodile and olive ridley turtle.