Water Resources(Unit - III, Chapter 2, Indian Geography)

1. Water Resources of India: Availability and Distribution

India receives nearly 4,000 cubic km of precipitation annually from various sources . However, the total available surface water and replenishable groundwater is estimated at only 1,869 cubic km . 

Due to topographical, hydrological, and other constraints, only about 60 per cent (1,122 cubic km) of this available water can actually be put to beneficial use .

I. Surface Water Resources

Surface water exists in four primary sources: rivers, lakes, ponds, and tanks .

• River Systems: There are approximately 10,360 rivers and their tributaries in India, each longer than 1.6 km .

• Catchment Potential: The mean annual flow in all the river basins in India is estimated to be 1,869 cubic km . However, the distribution is highly uneven.

• Regional Variation: The Ganga, Brahmaputra, and Indus basins, which account for about one-third of the total catchment area, contain 60 per cent of India’s total surface water resources .

• Utilization Constraints: In many Peninsular rivers like the Godavari, Krishna, and Kaveri, a much larger proportion of the water potential has been utilized compared to the Himalayan rivers, which still have vast untapped potential .

II. Groundwater Resources

The total replenishable groundwater resource in the country is about 432 cubic km .

• Distribution: The Ganga and Brahmaputra basins have about 46 per cent of the total replenishable groundwater resources .

• Utilization Levels: The level of groundwater utilization is relatively high in the river basins of north-western India (Punjab, Haryana, Rajasthan) and parts of South India (Tamil Nadu) .

• State-wise Trends: States like Punjab, Haryana, and Rajasthan utilize a very high proportion of their groundwater, primarily for agriculture . Conversely, states like Chhattisgarh, Odisha, and Kerala utilize only a small fraction of their potential . If the current trend of high withdrawal continues, it will lead to severe water scarcity and environmental issues in high-utilization states .

III. Lagoons and Backwaters

India has a long coastline and a very indented coast in some states, leading to the formation of many lagoons and lakes .

• States: These are most prominent in Kerala, Odisha, and West Bengal .

• Usage: While these water bodies are generally brackish (salty), they are vital for fishing and irrigating certain varieties of paddy crops and coconut trees .

2. Water Demand and Utilization

India has traditionally been an agrarian economy, and about two-thirds of its population has been dependent on agriculture . Consequently, development goals post-Independence focused on expanding irrigation to ensure food security .

I. Sectoral Consumption

• Agriculture: This is the dominant user of water in India. It accounts for 89 per cent of surface water and 92 per cent of groundwater utilization .

• Industrial and Domestic: Currently, these sectors account for a small share (9% surface/5% ground for domestic; 2% surface/3% ground for industries) . However, as the country industrializes and urbanizes, their share of water demand is projected to rise significantly .

II. Demand for Irrigation

Irrigation is essential in India due to the spatio-temporal variability of rainfall .

• Need: Large parts of the country are deficient in rainfall and drought-prone (e.g., North-western India and the Deccan Plateau) . Even in high-rainfall areas like West Bengal and Bihar, breaks in the monsoon or its early retreat can be detrimental to crops .

• Green Revolution Support: The success of the Green Revolution in Punjab, Haryana, and Western Uttar Pradesh was entirely dependent on the expansion of irrigation .

• Multi-cropping: Irrigation has made it possible to grow multiple crops in a year. In West Bengal and Bihar, farmers grow three crops of rice—aus, aman, and boro—in a single year provided irrigation is available .

3. Emerging Water Problems

The increasing demand for water, coupled with a growing population and deteriorating quality, has created a multifaceted crisis .

I. Deterioration of Water Quality

Water quality refers to the purity of water or water without unwanted foreign substances . Water becomes "polluted" when its concentration of suspended particles and organic/inorganic substances increases to the point where its self-purifying capacity is exceeded .

• Sources of Pollution:

  • Industrial Effluents: Discharge of toxic chemical residuals, heavy metals, and dust from industries like leather, pulp, and chemicals .

  • Agricultural Runoff: Modern agriculture uses vast amounts of inorganic fertilizers, pesticides, and herbicides, which wash into rivers and lakes .

  • Domestic Sewage: Untreated waste from urban centers is often dumped directly into water bodies .

• Highly Polluted Rivers: The Yamuna is the most polluted river in India between Delhi and Etawah . The Ganga faces severe pollution at Kanpur and Varanasi .

II. Scarcity and Depletion

Over-extraction of groundwater has led to a falling water table in many states .

• Chemical Contamination: Depletion has increased the concentration of toxic substances. For example, over-withdrawal has led to high fluoride levels in parts of Rajasthan and Maharashtra, and arsenic contamination in West Bengal and Bihar .

• Per Capita Availability: Due to population growth, the per capita availability of water is declining steadily .

4. Water Conservation and Management

Given that the supply of fresh water is limited and the demand is increasing, there is an urgent need for conservation .

I. Prevention of Pollution

Strict enforcement of environmental laws like the Water (Prevention and Control of Pollution) Act 1974 is necessary . However, effective implementation remains a challenge. Public awareness and community participation are critical for reducing ritualistic and domestic pollution in rivers .

II. Recycle and Reuse

Encouraging the use of low-quality water for purposes other than drinking can save vast amounts of fresh water .

• Examples: Using reclaimed wastewater for cooling in thermal power plants, fire-fighting, or gardening .

III. Watershed Management

Watershed management involves the efficient management and conservation of all natural resources—land, water, plants, and animals—within a single hydrological unit (watershed) .

• Objective: To bring about a balance between natural resources on one hand and society on the other .

• Key Programs:

  • Haryali: A central government-sponsored project executed by Gram Panchayats with people’s participation .

  • Neeru-Meeru: (Water and You) program in Andhra Pradesh .

  • Arvary Pani Sansad: (Alwar, Rajasthan) involved the construction of various water-harvesting structures like johads and check dams .

IV. Rainwater Harvesting

Rainwater harvesting is a method to capture and store rainwater for various uses and to recharge groundwater aquifers .

• Benefits: It is low-cost and eco-friendly; it stops soil erosion, improves water quality (by diluting pollutants like fluoride), and provides water security during dry seasons .

• Traditional Methods: Include storage in tanks (tanka or kund) in Rajasthan .

• Modern Compulsion: Tamil Nadu is the first state in India to make rooftop rainwater harvesting structures compulsory for all buildings .

V. National Water Policy 2012

The policy emphasizes the following priorities:

• Treating water as an economic good to promote conservation .

• Providing potable water to all human beings and livestock .

• Promoting community-based management of water resources .

• Prioritizing social equity and integrated water resource management .

5. Case Study: Success in Water Management

Ralegan Siddhi (Ahmadnagar, Maharashtra): 

This village provides a classic example of transformation through watershed development .

• The Problem: The village suffered from extreme poverty, illegal liquor trade, and severe water scarcity .

• The Solution: Led by Anna Hazare, the community built percolation tanks and check dams to trap every drop of rain .

• Outcome: The groundwater level rose significantly, allowing for multiple crops and the cultivation of diverse vegetables . The village became self-sufficient, and social evils like untouchability and alcoholism were eradicated through collective community action .

Summary Table for CUET Aspirants