Water Resources — Important Questions

Answers

• Unequal distribution of rainfall across regions and seasons.
• Over-exploitation of surface and groundwater resources, particularly for irrigation.
• Growing population leading to increased demand for domestic use and food production.
• Pollution of water sources, rendering them unusable.
• Inefficient water management and unequal access.
  2. The key objectives of the Jal Jeevan Mission (JJM) are:
• To provide every rural household with an assured supply of potable piped water.
• To ensure this supply is available on a regular, long-term basis.
• To provide water at a service level of 55 litres per capita per day.
• To ensure the functionality of tap water connections in rural areas.
  3. Ancient India had a rich tradition of water management. Sophisticated hydraulic structures were built to harvest and manage water. Examples include:
• Sringaverapura (near Allahabad) had a sophisticated rainwater harvesting system in the first century B.C.
• During the Mauryan period, dams, lakes, and extensive irrigation systems were built.
• Evidences of sophisticated irrigation works are found in Kalinga (Odisha), Nagarjunakonda (Andhra Pradesh), Bennur (Karnataka), and Kolhapur (Maharashtra).
• The Bhopal Lake, one of the largest artificial lakes of its time, was built in the 11th century.
• The tank in Hauz Khas, Delhi, was constructed by Allauddin Khilji in the 13th-14th century for water supply.
  4. (a) 'Tankas' are underground tanks, often as large as a room, built in traditional homes in Rajasthan. They were a crucial part of rooftop rainwater harvesting, collecting and storing precious rainwater during the monsoon for use during the dry periods, making them a reliable source of drinking water in an arid region.
  (b) The practice is declining primarily because the availability of water from the perennial Indira Gandhi Canal has reduced the perceived need for traditional storage. Some villagers may also find maintaining these tanks labor-intensive compared to readily available piped water.
  (c) Neglecting traditional systems can lead to a loss of valuable indigenous knowledge and techniques. It makes communities vulnerable again to water scarcity if modern systems fail or if the canal water supply is disrupted. It also means losing out on the pure quality of 'Palar Pani' and the cooling benefits of underground rooms connected to tankas.
  5. Industrialisation and urbanisation contribute to water scarcity in several ways:
• Increased Demand: Both industries and growing urban populations require vast quantities of water for their operations and domestic needs, respectively.
• Over-exploitation of Groundwater: Industries and urban centres often rely on groundwater, leading to its depletion and falling water tables.
• Water Pollution: Industrial effluents, if not treated properly, pollute freshwater bodies, making the water unusable.
• Energy Needs: Industries require power, much of which is generated through hydroelectric projects, which themselves consume and alter water resources.
• Urban Lifestyles: Dense populations and modern urban lifestyles increase water and energy demands.
  6. The statement "Water, Water Everywhere, Not a Drop to Drink" highlights the paradox of abundant water on Earth, yet a severe shortage of safe, usable freshwater. This is largely due to water pollution. Various sources contaminate freshwater bodies:
• Domestic Waste: Sewage from households, if not treated, releases organic matter and pathogens into rivers and lakes.
• Industrial Effluents: Industries discharge chemical wastes, heavy metals, and other toxic substances.
• Agricultural Runoff: Pesticides, herbicides, and fertilisers used in farming are washed into water bodies, contaminating them and leading to eutrophication.
  This pollution renders large quantities of water unfit for drinking, agriculture, and other essential uses, leading to scarcity even in areas with high water availability.
  7. Multi-purpose river projects are large-scale projects where a river is dammed to serve multiple objectives.
  Benefits:
• Irrigation: They provide water for agriculture, especially in dry areas, increasing food production. For example, the Bhakra-Nangal project uses water for irrigation.
• Electricity Generation: Dams are used to generate hydroelectric power, which is a crucial source of energy for industries and households.
• Flood Control: By regulating the flow of rivers, dams can help prevent devastating floods.
• Other Uses: They also provide water for domestic and industrial supply, inland navigation, recreation, and fish breeding.
  8. Two practical measures a local community could implement to conserve water include:
• Promoting Water-Saving Fixtures: Encouraging the use of low-flow taps, showerheads, and dual-flush toilets in households and public spaces. Regular maintenance checks can be organized to fix leaky faucets and pipes promptly.
• Water-Wise Gardening and Landscaping: Educating residents on drought-tolerant plants and efficient irrigation techniques like drip irrigation for gardens. Promoting the use of recycled greywater for gardening where feasible and implementing community rainwater harvesting systems for public green spaces.
  9. Water pollution occurs when contaminants are introduced into natural water bodies, rendering them harmful.
• Domestic Wastes: Sewage from households contains organic matter, pathogens (bacteria, viruses), and nutrients. When discharged untreated into rivers, it depletes dissolved oxygen, harms aquatic life, and spreads diseases.
• Industrial Wastes: Industries release a wide array of pollutants, including heavy metals (like lead, mercury), toxic chemicals, acids, alkalis, and organic compounds. These can be acutely poisonous to aquatic organisms and humans, and can persist in the environment for long periods.
• Agricultural Runoff: Chemicals like pesticides, herbicides, and synthetic fertilisers applied to crops are washed off by rain or irrigation into nearby water bodies. Pesticides can directly poison aquatic life and accumulate in the food chain. Fertilisers lead to eutrophication, causing excessive algal growth, oxygen depletion, and fish kills.
  10. Large multi-purpose river projects, while offering benefits, also raise significant concerns:
• Environmental Impacts:
• Habitat Destruction and Fragmentation: Reservoirs submerge vast areas of land, destroying existing vegetation and habitats, and displacing wildlife. Dams fragment rivers, obstructing the migration of aquatic fauna, especially for spawning.
• Sedimentation: Dams trap sediment, leading to poor sediment flow downstream and excessive sedimentation in the reservoir. This can reduce the dam's storage capacity and make riverbeds rockier, affecting aquatic habitats.
• Altered Flow Regimes: Regulating river flow can alter natural ecological processes and affect downstream ecosystems.
• Water-borne Diseases: Stagnant water in reservoirs can become breeding grounds for disease vectors like mosquitoes (malaria, dengue).
• Induction of Earthquakes: Some large dams have been linked to induced seismicity.
• Social Impacts:
• Displacement of People: The creation of reservoirs often leads to the displacement of large populations, including tribal communities and farmers, causing loss of livelihoods, homes, and cultural heritage.
• Water Disputes: Diversion of water can lead to inter-state or international water disputes.
• Economic Impacts:
• High Costs: These projects involve massive financial investment.
• Ecological Consequences: Changes in cropping patterns due to irrigation can lead to land degradation like soil salinisation.
  11. (a) The vision was to use integrated water resources management approach to drive national development and progress, overcoming the challenges inherited from the colonial era.
  (b) Jawaharlal Nehru referred to dams as the 'temples of modern India' because he believed they would integrate the development of agriculture and the village economy with rapid industrialisation and the growth of the urban economy.
  (c) Modern criticisms include:
• Failure to control floods effectively due to sedimentation.
• Triggering floods because of excessive sedimentation in reservoirs.
• Causing poor sediment flow and rockier stream beds downstream.
• Fragmenting rivers and hindering aquatic fauna migration.
• Submerging vegetation and soil, leading to decomposition.
• Inducing earthquakes and causing water-borne diseases and pests.
• Altering cropping patterns towards water-intensive crops, leading to ecological consequences like soil salinisation.
  12. Rainwater harvesting is the technique of collecting and storing rainwater for various uses.
  Traditional Methods:
• Khadins and Johads: In arid and semi-arid regions of Rajasthan, 'khadins' (artificially constructed bunds or channels that hold rainwater and allow it to seep into the soil) and 'johads' (earthen check dams that collect rainwater) were used to allow water to stand and moisten the soil for agriculture.
• Rooftop Rainwater Harvesting: In Rajasthan, houses traditionally had underground tanks ('tankas') connected to sloping roofs via pipes to store drinking water. The first rain was not collected to clean the roofs and pipes, followed by the collection of subsequent showers.
  13. (a) Any two of the following states: Gujarat, Haryana, Karnataka, Madhya Pradesh, Maharashtra, Rajasthan, and Uttar Pradesh.
  (b) The primary goal of the Atal Bhujal Yojana is to improve groundwater management and bring about behavioural changes in communities to conserve and manage water resources effectively in water-stressed areas.
  (c) Beyond infrastructure, the scheme aims to foster community participation and promote behavioural changes. It encourages a shift from a consumption-oriented approach to one of conservation and smart water management, empowering local communities to take ownership of their water resources.
  14. The Pradhan Mantri Krishi Sinchayee Yojana (PMKSY) aims to:
• Ensure physical access to water on the farm ("Har Khet Ko Pani" - water for every farm).
• Expand the area under assured irrigation.
• Improve on-farm water use efficiency to reduce wastage and increase water availability ("Per Drop More Crop").
• Introduce sustainable water conservation practices and irrigation technologies.
• Ultimately, promote rural prosperity by enhancing agricultural productivity through better water management.
  15. The bamboo drip irrigation system in Meghalaya is a 200-year-old technique that uses bamboo pipes to tap stream and spring water from hilltops. Water is transported over hundreds of metres via a network of bamboo channels and pipes by gravity. The flow is controlled by manipulating the pipes, eventually reducing to a trickle (20-80 drops per minute) at the plant's root. The final channel sections ensure water is dropped precisely near the plant's roots.
  16. (a) A potential reason for the dam's ineffectiveness could be excessive sedimentation in the reservoir, which reduces its storage capacity and ability to hold back large volumes of water during heavy rainfall. Alternatively, the dam might have been designed for a certain capacity, and the current rainfall event has exceeded that design limit.
  (b) Ecological consequences include:
• Submergence of existing vegetation and soil, leading to decomposition.
• Alteration of river habitats and disruption of aquatic life migration patterns (e.g., for spawning).
• Changes in downstream sediment transport, affecting riverbed composition and nutrient supply.
  (c) Any two other uses:
• Electricity generation (hydel power).
• Water supply for domestic and industrial uses.
• Recreation.
• Inland navigation.
• Fish breeding.
  17. Effect on Aquatic Life: Dams create barriers that fragment rivers, making it difficult or impossible for aquatic fauna, such as fish, to migrate upstream or downstream, especially for spawning. This disruption can significantly impact fish populations and the river's ecosystem balance. The altered flow regimes and sediment deposition can also create rockier stream beds, changing habitats.
  Effect on Sediment Flow: Dams trap a significant amount of sediment that would naturally flow downstream. This leads to a reduction in sediment load in the river downstream of the dam, which can cause erosion of riverbeds and banks. Internally, the accumulation of sediment in the reservoir reduces its storage capacity over time.
  18. (a) Tamil Nadu.
  (b) Shillong, Meghalaya.
  (c) The basic principle involves collecting rainwater that falls on the sloping roofs of houses using pipes. This collected water is then channelled, often filtered, and stored in underground tanks or sumps for later use. Excess water can also be directed to recharge wells or existing borewells to replenish groundwater.
  19. In Rajasthan, 'Palar Pani' is the term commonly used for rainwater, or surface runoff collected during the monsoon. It is considered the purest form of natural water and was traditionally stored in 'tankas' for drinking purposes, serving as a reliable source when other water sources dried up, especially during summers.
  20. Inter-state water disputes arise when the construction or operation of a water project by one state affects the water availability or flow in another state. The Krishna-Godavari dispute is an example where the Maharashtra government's plan for a multi-purpose project at Koyna, diverting more water, faced objections from the Karnataka and Andhra Pradesh governments. They argued that this diversion would reduce the downstream flow in their states, adversely impacting their agriculture and industries. Such disputes highlight the challenges of managing shared river resources among different states with competing demands.