Chapter 6 Water Resources

Water is a vital resource that faces increasing scarcity challenges due to growing demand, over-utilization, and pollution. Despite being a cyclic resource with seemingly abundant global supply (covering ~71% of Earth's surface), only a tiny fraction (~3%) is freshwater, and only a very small portion of this freshwater is easily accessible and usable by humans.

The availability of freshwater is not uniform across space and time, leading to tensions and disputes over its sharing and control.

Effective assessment, efficient use, and conservation of water are therefore crucial for ensuring sustainable development.

This chapter explores India's water resources, their geographical distribution, how they are used by different sectors, and methods for conservation and management.

Water Resources Of India

India holds a significant share of global resources: about 2.45% of the world's surface area, 4% of its water resources, but about 16% of the world's population.

The total amount of water received from precipitation (rain, snow, etc.) in India annually is approximately 4,000 cubic km.

The estimated total availability from surface water and replenishable groundwater combined is 1,869 cubic km. However, due to geographical, hydrological, and other constraints, only about 60% (approximately 1,122 cubic km) of this can be effectively utilized by humans.

Surface Water Resources

The main sources of surface water in India are rivers, lakes, ponds, and tanks.

India has numerous rivers and their tributaries. The estimated average annual flow in all river basins is 1,869 cubic km. However, only about 690 cubic km (about 32%) of this surface water is considered utilizable due to various constraints.

The amount of water flowing in a river depends on the size of its catchment area (river basin) and the amount of rainfall received within that area.

Rivers like the Ganga, Brahmaputra, and Indus have vast catchment areas. The Ganga, Brahmaputra, and Barak river basins together cover only about one-third of India's total area but contribute 60% of the country's total surface water resources due to high precipitation in their catchments.

While much of the water flow in major South Indian rivers (Godavari, Krishna, Kaveri) has been harnessed for use, the potential in the larger Brahmaputra and Ganga basins is yet to be fully exploited.

Groundwater Resources

The total replenishable groundwater resources in India are estimated to be about 432 cubic km.

The level of groundwater utilization varies regionally:

• It is very high in states located in the northwestern region (Punjab, Haryana, Rajasthan) and parts of South India (Tamil Nadu).
• Some states, such as Chhattisgarh, Odisha, and Kerala, utilize only a small fraction of their groundwater potential.
• States like Gujarat, Uttar Pradesh, Bihar, Tripura, and Maharashtra utilize their groundwater resources at a moderate rate.

If current trends of groundwater extraction continue, the demand for water will likely exceed available supplies, potentially leading to developmental setbacks and social conflicts.

Lagoons And Backwaters

India has an extensive coastline, and in certain states, the coast is indented, leading to the formation of numerous lagoons and backwaters. States like Kerala, Odisha, and West Bengal possess significant surface water resources in these coastal water bodies.

While the water in lagoons is generally brackish (a mix of fresh and saltwater), it is still valuable and used for fishing and irrigating specific crops adapted to such conditions, including certain varieties of paddy, coconut, and others.

Water Demand And Utilisation

India has historically been an agrarian economy, with a large majority of its population dependent on agriculture. Consequently, increasing agricultural production through irrigation has been a high priority since Independence.

Major multipurpose river valley projects (e.g., Bhakra-Nangal, Hirakud, Damodar Valley, Nagarjuna Sagar, Indira Gandhi Canal Project) were undertaken to facilitate irrigation.

Currently, India's water demand is predominantly for irrigation purposes.

Utilisation of surface water and groundwater varies significantly across sectors:

• Agriculture: Accounts for the largest share, using 89% of surface water and 92% of groundwater.
• Industrial Sector: Utilizes a much smaller proportion, only 2% of surface water and 5% of groundwater.
• Domestic Sector: Accounts for 9% of surface water use and a smaller share of groundwater.

Overall, the agricultural sector's share in total water utilization is much higher than industries or domestic use. However, with future economic development and increasing urbanisation, the shares of the industrial and domestic sectors in total water demand are projected to rise.

Demand Of Water For Irrigation

Water is primarily used for irrigation in agriculture due to significant variations in rainfall across India, both spatially (different regions) and temporally (different seasons).

Large parts of India, particularly the northwest and the Deccan plateau, receive insufficient rainfall and are prone to drought, making irrigation essential for cultivation.

Winter and summer seasons are predominantly dry in most areas, necessitating irrigation for farming during these periods.

Even in regions with high annual rainfall (like West Bengal and Bihar), breaks in the monsoon or its failure can cause dry spells that are detrimental to agriculture.

Certain crops, such as rice, sugarcane, and jute, have very high water requirements that can only be met through irrigation.

Irrigation facilitates multiple cropping (growing more than one crop in a year) and leads to higher agricultural productivity compared to unirrigated land.

Modern high-yielding varieties (HYVs) of crops require a consistent supply of moisture, which is made possible by developed irrigation systems. This is why the Green Revolution strategy, which relied on HYVs, was largely successful in well-irrigated areas like Punjab, Haryana, and western Uttar Pradesh.

In these northwestern states, over 85% of the net sown area is irrigated, primarily using wells and tubewells (76.1% in Punjab, 51.3% in Haryana).

This high level of groundwater utilization has led to severe groundwater depletion in these states.

Excessive groundwater extraction in some states (like Rajasthan and Maharashtra) has increased fluoride concentration in groundwater, while in parts of West Bengal and Bihar, it has led to higher arsenic concentrations, posing serious health risks.

Emerging Water Problems

India faces critical water problems stemming from both quantity and quality issues.

The per capita availability of water is declining rapidly due to continuous population growth.

Compounding this problem is the increasing pollution of available water resources by industrial, agricultural, and domestic waste, which further limits the supply of usable water.

Deterioration Of Water Quality

Water quality refers to the purity of water, specifically the absence of unwanted foreign substances. Water becomes polluted when it is contaminated by materials like microorganisms, chemicals, industrial effluents, and other waste products.

These contaminants degrade water quality, making it unfit for human use and harming aquatic ecosystems.

Toxic substances entering water bodies (lakes, streams, rivers, oceans) can dissolve or remain suspended, causing widespread pollution. Pollutants can also seep underground and contaminate groundwater.

The Ganga and Yamuna rivers are among the most severely polluted rivers in India.

Water Conservation And Management

Given the declining availability of freshwater and increasing demand, conserving and efficiently managing water resources is essential for sustainable development.

Since desalination of seawater is expensive, especially for large-scale use, India must focus on effective conservation policies, laws, and measures.

Strategies involve developing water-saving technologies, preventing pollution, and promoting practices like watershed development, rainwater harvesting, water recycling and reuse, and conjunctive use of surface and groundwater to ensure long-term water supply.

Prevention Of Water Pollution

Water resources are degrading rapidly due to pollution.

Rivers in India are generally cleaner in their upper reaches, but as they flow through plains, they become increasingly polluted due to intensive use and the discharge of waste from agricultural (fertilizers, insecticides), domestic (sewage, solid waste), and industrial sources.

The concentration of pollutants is particularly high during the dry summer season when river flow is low.

Monitoring by the Central Pollution Control Board (CPCB) indicates that organic and bacterial contamination are major sources of river pollution.

Highly polluted stretches include the Yamuna between Delhi and Etawah, the Sabarmati at Ahmedabad, the Gomti at Lucknow, and parts of many other rivers (Kali, Adyar, Cooum, Vaigai, Musi, Ganga at Kanpur and Varanasi).

Groundwater pollution is also a concern, with high levels of heavy/toxic metals, fluoride, and nitrates found in various parts of the country.

Legislative efforts like the Water (Prevention and Control of Pollution) Act 1974 and the Environment Protection Act 1986 have not been fully effective in controlling pollution.

There is a strong need for public awareness campaigns about the importance of water and the impacts of pollution. Public action can be crucial in reducing pollutants from various sources.

Recycle And Reuse Of Water

Recycling and reusing water is another strategy to increase freshwater availability.

Using water of lower quality, such as treated wastewater, can be beneficial for industrial purposes like cooling and fire fighting, potentially reducing their water costs.

In urban areas, water used for bathing or washing utensils can be reused for gardening.

Recycling water used for washing vehicles can also be diverted for gardening purposes.

These practices conserve higher quality water for essential uses like drinking. While water recycling is currently limited, there is significant potential for expanding its use.

Watershed Management

Watershed management focuses on the efficient management and conservation of both surface water and groundwater resources within a specific drainage basin (watershed).

Key aspects include preventing runoff and promoting groundwater storage and recharge through methods like building percolation tanks, recharge wells, and check dams.

In a broader sense, watershed management encompasses conserving, regenerating, and judiciously using all resources (land, water, plants, animals, human) within the watershed.

The goal is to balance resource use with the needs of the community and the environment. Community participation is vital for the success of watershed development projects.

Both Central and State Governments in India have launched numerous watershed development programs, some also implemented by NGOs.

Haryali is a Central Government sponsored project aimed at enabling rural communities to conserve water for various uses (drinking, irrigation, fisheries, afforestation) through Gram Panchayats and people's involvement.

State-level initiatives like Neeru-Meeru (Andhra Pradesh) and Arvary Pani Sansad (Rajasthan) have successfully implemented water-harvesting structures with community participation. Tamil Nadu has mandated rainwater harvesting structures in all new buildings.

While some watershed development projects have successfully revitalized local environments and economies (e.g., Ralegan Siddhi), the program is still developing nationwide. Raising awareness among the public about the benefits of watershed management and promoting an integrated water resource management approach are essential for ensuring sustainable water availability.

Answer:

Rainwater Harvesting

Rainwater harvesting is a technique to collect and store rainwater from rooftops, open spaces, or other surfaces for direct use or for recharging groundwater aquifers.

It is a cost-effective and environmentally friendly method to conserve water by directing rainwater into storage structures, pits, wells, or borewells.

Benefits of rainwater harvesting include:

• Increasing local water availability.
• Preventing the decline of the groundwater table.
• Improving groundwater quality by diluting contaminants like fluoride and nitrates.
• Reducing soil erosion and preventing urban flooding.
• Preventing saltwater intrusion into freshwater aquifers in coastal areas when used for recharge.

Traditional rainwater harvesting methods have been practiced in India for centuries using surface storage bodies like lakes, ponds, and tanks. In Rajasthan, traditional underground tanks called 'Kund' or 'Tanka' are used to store harvested rainwater.

There is significant potential for expanding rainwater harvesting, especially in urban areas where water demand often exceeds supply. Harvesting rainwater reduces reliance on groundwater, saving energy needed for pumping, as recharge helps raise the groundwater table. Rainwater harvesting is increasingly being adopted on a large scale in many states across India.

Other potential long-term solutions for water problems in India include desalination of water (especially in coastal areas or for brackish water in arid/semi-arid regions) and inter-linking of rivers to transfer water from surplus to deficit basins. However, these solutions involve significant technical, environmental, and economic challenges.

For individuals, households, and communities, the issue of pricing water is also becoming increasingly relevant in managing demand.

Highlights of India’s National Water Policy, 2002:

The policy prioritized water allocation in a specific order: drinking water > irrigation > hydro-power > navigation > industrial > other uses. Key approaches included:

• Including drinking water components in irrigation/multipurpose projects, especially where no alternative sources exist.
• Prioritizing drinking water for humans and animals.
• Regulating groundwater exploitation.
• Regularly monitoring water quality and implementing improvement programs.
• Improving water utilization efficiency across all sectors.
• Promoting awareness about water scarcity and conservation through education, regulation, incentives, and disincentives.

Jal Kranti Abhiyan (2015-16):

Launched by the Government of India, this campaign aims to ensure water security amidst growing population, economic development, and climate change. It recognizes traditional knowledge and involves local bodies, NGOs, and citizens.

Activities included selecting 'Jal Grams' (water-stressed villages) for intervention, identifying model command areas for efficient water use, focusing on pollution abatement, water conservation, artificial recharge, reducing groundwater pollution, constructing arsenic-free wells, and conducting mass awareness campaigns through various media.

The Abhiyan seeks to connect water security with livelihood and food security.

Exercises

This section includes exercises covering the availability, distribution, utilization, problems, and conservation methods of water resources in India, providing students with opportunities to review and apply their understanding.

Choose The Right Answers Of The Following From The Given Options

Multiple-choice questions testing recall of facts and understanding of key concepts related to water resources.

Answer The Following Questions In About 30 Words.

Short answer questions requiring brief explanations of factors causing water depletion, reasons for high groundwater development in certain states, expected changes in agricultural water use share, and potential impacts of contaminated water.

Answer The Following Questions In About 150 Words.

Longer answer questions prompting detailed discussions on water resource availability and distribution, how depleting resources can lead to conflicts, and the significance of watershed management for sustainable development.