Water Resources (India)

Water Resources Of India

India is endowed with a rich and diverse water resource base, comprising surface water from its numerous rivers and groundwater aquifers. However, the availability and quality of this water are unevenly distributed across regions and seasons, leading to significant challenges.

Surface Water Resources

Surface water in India primarily comprises water flowing in rivers, lakes, ponds, and reservoirs.

• Rivers: India has a vast river network. Major river systems include the Ganges-Brahmaputra-Meghna system, the Indus system, and the Peninsular river systems like Godavari, Krishna, Cauvery, Narmada, and Tapi. These rivers are crucial sources for irrigation, drinking water, hydropower, and navigation.
• Lakes and Ponds: Numerous natural and artificial lakes and ponds are scattered across the country, serving as sources for local water supply and irrigation.
• Reservoirs: Large dams store water from rivers, creating vast reservoirs used for multi-purpose projects (irrigation, power, flood control).
• Estimated Potential: India's estimated annual surface water potential is about 1,723 billion cubic metres (BCM), of which only about 1,123 BCM can be utilized due to topographical and other constraints.

Groundwater Resources

Groundwater is a critical source of water, especially in regions with low surface water availability or erratic rainfall. It is accessed through wells, tube wells, and borewells.

• Availability: Groundwater constitutes a significant portion of India's utilizable water resources. It is particularly important for irrigation in states like Punjab, Haryana, Uttar Pradesh, and parts of Rajasthan.
• Estimation: The estimated groundwater potential in India is about 433 BCM.
• Over-exploitation: In many parts of the country, groundwater is being extracted at a rate faster than its natural replenishment, leading to declining water tables, drying up of wells, and increased extraction costs. This is a major concern, especially in the Indo-Gangetic plains and parts of the Deccan Plateau.

Lagoons And Backwaters

Lagoons and backwaters are coastal bodies of water, often brackish, formed where rivers meet the sea or through coastal geological processes. While primarily brackish, they hold significant water resources.

• Location: Found along India's long coastline, most notably in Kerala (where they form an extensive network), Tamil Nadu, Andhra Pradesh, Odisha, and West Bengal.
• Resources: Hold substantial water resources, though largely brackish. They are vital for local ecosystems, fisheries, and, in some areas like Kerala, for inland navigation and tourism.
• Potential: Potential exists for their use in aquaculture and, in some cases, for desalination or specific industrial uses, though preservation of their unique ecosystems is also critical.

Water Demand And Utilisation

Water demand in India is driven by various sectors, with agriculture being the largest consumer. Efficient management of this demand is crucial for sustainable development.

Demand Of Water For Irrigation

Irrigation accounts for the largest share of water utilization in India, typically around 80-85% of the total water demand. This is due to the country's reliance on agriculture, which is often dependent on monsoon rains.

• Necessity: Irrigation ensures crop yields, protects against drought, and allows for multiple cropping seasons in many regions.
• Methods of Irrigation:
• Canals: Major source of irrigation in northern plains, drawing water from rivers and dams.
• Dug Wells: Traditional method, common in peninsular India.
• Tube Wells: Increasingly popular, tapping groundwater for irrigation, especially in areas with shallow water tables.
• Other Sources: Tanks, ponds, rainwater harvesting.
• Challenges:
• Over-extraction of Groundwater: Leading to declining water tables.
• Inefficient Use: Traditional irrigation methods often lead to significant water loss through evaporation and seepage.
• Water Logging and Salinization: Improper irrigation practices can lead to waterlogging and accumulation of salts in the soil, reducing fertility.
• Promoting Efficient Use: There is a growing emphasis on promoting water-saving irrigation techniques like drip irrigation and sprinkler systems, especially in water-scarce regions.

Emerging Water Problems

India faces significant and growing challenges related to water resources, stemming from increased demand, pollution, and the impacts of climate change.

Deterioration Of Water Quality

The quality of both surface and groundwater resources in India is deteriorating rapidly due to various human activities.

• Sources of Pollution:
• Untreated Sewage: A large proportion of domestic wastewater is discharged into rivers and water bodies without adequate treatment, introducing pathogens, organic matter, and nutrients.
• Industrial Effluents: Industries release toxic chemicals, heavy metals (mercury, lead, arsenic), and other pollutants into water sources.
• Agricultural Runoff: Pesticides, herbicides, and chemical fertilizers used in agriculture are washed into rivers and groundwater, contaminating them.
• Solid Waste: Improper disposal of urban and industrial solid waste, often dumped in or near water bodies, leads to land and water pollution.
• Thermal Pollution: Discharge of hot water from power plants and industries into water bodies can harm aquatic life.
• Impacts:
• Health Hazards: Contaminated water is a major cause of waterborne diseases like cholera, typhoid, dysentery, and hepatitis, leading to significant public health problems.
• Ecological Damage: Pollution harms aquatic ecosystems, reduces biodiversity, and can lead to eutrophication (excessive nutrient enrichment).
• Reduced Usability: Polluted water is unfit for drinking, irrigation, and industrial use, increasing the cost of water treatment.
• Government Initiatives: Efforts like the National River Conservation Plan (NRCP) and the National Mission for Clean Ganga (NMCG) aim to tackle river pollution, but challenges remain in effective implementation and enforcement.

Other emerging problems include increasing water scarcity due to over-extraction and climate change, and conflicts over water sharing among states and nations.

Water Conservation And Management

Effective water conservation and management are critical for ensuring sustainable water availability for all uses and protecting water resources from pollution and degradation.

Prevention Of Water Pollution

This involves controlling the discharge of pollutants into water bodies:

• Treatment of Wastewater: Mandatory treatment of domestic sewage and industrial effluents before discharge into rivers or land.
• Regulation of Industrial Discharge: Strict enforcement of norms for industrial pollution control, including the use of ETPs (Effluent Treatment Plants) and zero-liquid discharge (ZLD) policies where feasible.
• Control of Agricultural Runoff: Promoting sustainable agricultural practices, reducing the use of chemical fertilizers and pesticides, and encouraging organic farming.
• Proper Waste Management: Scientific disposal of solid waste to prevent it from polluting water sources.
• Legislation and Enforcement: Strong environmental laws and their effective enforcement are crucial.

Recycle And Reuse Of Water

Recycling and reusing water can significantly reduce the demand for fresh water.

• Industrial Reuse: Many industries can treat their wastewater and reuse it for cooling, washing, or other non-potable purposes.
• Domestic Reuse: Treated wastewater can be used for gardening, flushing toilets, or recharging groundwater.
• Wastewater Treatment Plants: Establishing and improving the capacity of wastewater treatment facilities is key.

Watershed Management

Watershed management is the process of coordinating the development and management of water, land, and related resources in a watershed to maximize the resultant economic and social welfare in an equitable manner without compromising the sustainability of vital ecosystems.

• Objectives:
• Conservation of Soil and Water: Implementing measures like contour bunding, terracing, check dams, and afforestation to conserve soil and rainwater.
• Recharge of Groundwater: Building structures that promote the infiltration of water into the ground.
• Sustainable Land Use: Ensuring land is used appropriately based on its capability and the availability of water.
• Community Participation: Involving local communities in the planning and implementation of watershed development projects.
• Examples: Watershed management projects are crucial for improving water availability and agricultural productivity in rain-fed and drought-prone areas.

Rainwater Harvesting

Rainwater harvesting is the process of collecting and storing rainwater for various purposes, thereby reducing reliance on groundwater and surface water sources.

• Traditional Methods: India has a rich history of rainwater harvesting, including tanks, kunds, ahals, nadis, and inundation channels, adapted to local conditions. (See previous elaboration for details on Tankas in Rajasthan).
• Modern Techniques:
• Rooftop Rainwater Harvesting: Collecting rainwater from rooftops and storing it in tanks or recharging groundwater through percolation pits/wells.
• Surface Runoff Harvesting: Collecting runoff from paved surfaces via channels to storage or recharge structures.
• Groundwater Recharging Structures: Digging pits, trenches, creating recharge wells, and building check dams to replenish aquifers.
• Importance: Crucial for augmenting water supplies, recharging groundwater, preventing floods, and reducing water scarcity, especially in urban areas and arid regions.
• Government Initiatives: Schemes like the 'Jal Shakti Abhiyan' promote rainwater harvesting across the country.