Water covers three-fourths of the earth’s surface, yet only a small amount of it is fresh water that may be used. This freshwater is mostly acquired through surface runoff and groundwater, which are constantly refreshed and recharged by the hydrological cycle.

Water Scarcity: 

Water scarcity refers to less availability of water for fulfilling human and environment needs. 

Quantitative Aspects of Water Scarcity:

• Water availability changes over space and time due to seasonal and annual precipitation variations. Drought, for example, is widespread in Rajasthan
• Water scarcity is mostly caused by over-exploitation, excessive consumption, and unequal access to water among various social groups
• Growing Population: Increased domestic demand for food grains. Irrigation necessitates a large amount of water, and agriculture is the largest consumer of water
• Irrigation is one of the primary causes of falling groundwater levels. Falling groundwater levels may have a negative impact on people’s water supply and food security
• Increasing urbanisation and industrialisation: This has resulted in a massive increase in water demand as the number of urban centres with big and dense populations and urban lifestyles has not only increased water and energy requirements, but has also worsened the problem

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Qualitative Aspects of Water Scarcity:

• Water quality is degrading due to pollution from domestic trash, industrial waste, pesticides, and fertilisers used in agriculture, making it unsafe for human consumption.
• The Yamuna and Ganga rivers in India are heavily polluted, making them unfit for human consumption.

Water Conservation and Management

Multi-Purpose River Projects and Rainwater harvesting are some major techniques of Water Conservation and  Water Management.

Multi-Purpose River Projects:

• Dams made of stone rubble, reservoirs or lakes, embankments, and canals for irrigation were all created in ancient times
• Considered a Development Vehicle: They have been built since independence for conservation and integrated water management
• They are intended for irrigation, electricity generation, home and industrial water supply, flood control, recreation, inland navigation, and fish breeding
• Example of Multi-Purpose River Projects: The Bhakra-Nangal project in the Sutlej-Beas river basin and the Hirakud project in the Mahanadi river basin are two examples

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Issues with Large Dams and Multi-Purpose Projects:

• River regulation and damming alter their natural flow, resulting in poor sediment flow and excessive sedimentation at the reservoir’s bottom, resulting in rockier stream beds and worse habitats for the rivers’ aquatic species.
• Sedimentation also meant that the flood plains lost silt, a natural fertiliser that contributes to the problem of land degradation
• Dams break up rivers, making it impossible for aquatic life to migrate
• The reservoirs formed on the floodplains also submerge the existing plant and soil, causing it to decompose over time
• Large-Scale Displacement of Local Communities: It sparked environmental initiatives such as the ‘Narmada Bachao Andolan’ and the ‘Tehhri Dam Andolan’
• Irrigation has also altered cropping patterns in many areas, with farmers turning to more water-intensive and commercial crops. It had ecological effects, such as soil salinization
• Increased Social Inequality: Irrigation has also widened the social divide between wealthy landowners and landless poor
• Inter-State Water Disputes: These are becoming more widespread in terms of dividing the expenses and benefits of a multipurpose project
• Dams  have caused floods in the reservoir due to sedimentation. Furthermore, large dams have largely failed to prevent floods during periods of heavy rainfall
• They also produced earthquakes, water-borne diseases and pests, and pollution as a result of excessive water use

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Rainwater Harvesting:

It is a viable alternative, both socio-economically and environmentally.

• People in ancient India developed a wide range of strategies to capture rainwater, groundwater, river water, and flood water in accordance with local ecological conditions and water needs
• People developed diversion channels for agriculture in hill and mountainous regions, similar to the ‘guls’ or ‘kuls’ of the Western Himalayas
• ‘Rooftop Rainwater Harvesting’: This was a typical practice in Rajasthan to preserve drinking water
• In the Bengal Flood Plains, people created inundation channels to irrigate their land
• In dry and semi-arid regions, agricultural fields were transformed into rain-fed storage structures that enabled water to stand and saturate the soil, such as the ‘khadins’ in Jaisalmer and ‘Johads,’ as well as traditional underground water storage structures such as tankas in Rajasthan. Rainwater, or palar pani as it is known in these regions, is said to be the purest type of natural water

Conclusion

Our water resources, irregularly distributed in space and time, are under pressure due to major population change and increased demand. Access to reliable data on the availability, quality and quantity of water, and its variability, form the necessary foundation for sound management of water resources