- Rainfall in India is uncertain and uneven, so irrigation is necessary to protect crops from failure.
- Different crops and crop seasons (Kharif, Rabi, Zaid) require different amounts of water, which can be ensured only through irrigation.
- Many rivers are seasonal and carry water mainly during the monsoon, so irrigation helps in using river water effectively throughout the year.
- Soil type and land slope affect water needs—sandy and sloping areas require more frequent irrigation than clayey and plain areas.
- Irrigation increases agricultural productivity, supports multiple cropping and is essential to meet the food needs of the growing population.
Key Points
Key Points: Sources of Water
- Water resources include surface water (rivers, lakes, ponds) and groundwater (water stored below the earth).
- 97% of Earth’s water is saline (oceans); only 0.03% is available as fresh surface water for direct use.
- Surface water mainly comes from rainfall and melting of glaciers, but is easily polluted.
- Groundwater forms by percolation of rainwater and is stored in aquifers; it is the largest usable freshwater source.
- India depends on monsoon rains, and proper water management is essential for agriculture and economic growth.
Key Points: Need to Conserve Water
- Rising demand for water due to population growth, irrigation and industrialisation has reduced groundwater levels.
- Overexploitation of groundwater leads to a lowering of the water table.
- Loss of vegetation reduces rainfall and increases drought conditions.
- Agriculture uses more than 90% of freshwater, increasing pressure on water resources.
- Pollution of rivers, lakes and groundwater makes water unfit for direct use, increasing water scarcity.
Key Points: Water Conservation Practices > Rainwater Harvesting
- Rainwater harvesting is an eco-friendly method of collecting and storing rainwater to conserve water in India.
- It helps recharge groundwater, raise the water table, and improve water quality.
- Ancient communities developed region-specific harvesting methods based on rainfall, soil, and local needs.
- In hilly areas, channels like guls and kuls were used, while arid regions used khadins, johads, and tankas.
- Rooftop rainwater harvesting was widely practised, especially in Rajasthan, to store drinking water.
- Rainwater harvesting reduces floods, soil erosion, drain blockage, and surface runoff.
- It is compulsory in states such as Tamil Nadu and is widely used in places such as Shillong and Meghalaya, including in bamboo drip irrigation systems.
Key Points: Water Conservation Practices > Watershed Management
- A watershed is a geographical area from which water drains to a common point like a river, lake or pond.
- Watershed management means the planned conservation of soil and water resources in a watershed area.
- It includes preventing surface run-off by building small embankments and barriers.
- It helps in storing rainwater and recharging groundwater through percolation pits, recharge wells, borewells and dugwells.
- Watershed management ensures efficient use of water, reduces soil erosion and supports agriculture.
Key Points: Water Conservation Practices > Rooftop Rainwater Harvesting
- Rooftop rainwater harvesting collects rainwater from rooftops through pipes into storage tanks.
- The stored water is filtered and purified before use.
- Water quality improves as sediments settle at the bottom of the tank.
- The stored water is mainly used during summer water scarcity.
- It provides clean water for domestic use and promotes self-sufficiency in water supply.
Key Points: Water Conservation Practices > Recharging Groundwater Aquifers
- Recharge structures help rainwater percolate into the ground instead of flowing away as runoff.
- Borewells and dugwells collect filtered rooftop rainwater to raise the groundwater level.
- Recharge pits and percolation pits allow rainwater to seep slowly into the soil.
- Recharge trenches filled with porous materials help recharge groundwater from surface runoff.
- Permeable surfaces like grass and porous tiles reduce runoff and increase water infiltration.
Key Points: Irrigation
- Irrigation means supplying water to crops through artificial methods like canals, wells and tube wells.
- About 91–92% of freshwater in India is used for agricultural purposes.
- Rainfall in India is uneven and irregular, so irrigation is essential for stable farming.
- Nearly 55% of the net sown area still depends on rainfall for crop production.
- Proper irrigation ensures sustained agricultural production and supports overall economic development.
Key Points: Need for Irrigation
Key Points: Means of Irrigation
- Means of irrigation depend on factors like availability of water, soil type, crops, climate and relief.
- The main means of irrigation in India are well irrigation, tank irrigation and canal irrigation.
- Well irrigation includes surface wells and tube wells and is common in areas with good groundwater.
- Tank irrigation is mainly used in the Deccan Plateau, where the soil is hard and rivers are seasonal.
- Canal irrigation includes inundation and perennial canals, and is best suited for alluvial plains like the Gangetic and coastal plains.
Key Points: Well Irrigation
- Well irrigation uses groundwater obtained by digging wells and is common where the water table is shallow (about 10–15 m) and soil is soft.
- There are two types of wells: surface wells (lined/pucca and unlined/kuchha) and tube wells, which are deeper and use pumps.
- Well irrigation is cheap and simple, suitable for small farmers, but wells may dry up if groundwater is overused.
- Tubewells are deep wells (20–30 m or more) operated by electric or diesel pumps and can irrigate larger areas.
- Tubewell irrigation is reliable and perennial, but it is costly, needs power supply, and excessive use can deplete groundwater.
Key Points: Tank Irrigation
- Tank irrigation stores rainwater in natural or artificial depressions by building earthen or masonry bunds.
- It is common in the Deccan Plateau (Tamil Nadu, Andhra Pradesh, Telangana, Karnataka) due to uneven land, hard rock and seasonal rivers.
- Advantages: It conserves rainwater, raises groundwater level, is cheap to construct and supports irrigation and drinking water supply.
- Disadvantages: Tanks lose water by evaporation, depend on monsoon, get silted quickly and are mostly non-perennial.
- Tank irrigation is useful where wells and canals are difficult, but needs regular desilting and proper maintenance.
Key Points: Canal Irrigation
- Canal irrigation supplies river water to distant agricultural fields through artificial channels and is the second most important means of irrigation in India.
- There are two types of canals:
Inundation (non-perennial) canals work only during floods, while perennial canals provide water throughout the year using dams or barrages. - Canal irrigation is highly developed in the Northern Plains due to perennial rivers, flat land and soft alluvial soil.
- Advantages: It supports farming in dry regions, helps flood control, supplies fertile silt and boosted the Green Revolution in Punjab and Haryana.
- Disadvantages: Excess water causes waterlogging, salinity, soil infertility and canal construction is costly and wastes cultivable land.
Key Points: Modern Irrigation Methods
- Modern irrigation methods are scientific techniques developed to use water efficiently and overcome the limitations of traditional irrigation systems.
- Furrow irrigation supplies water through narrow channels between crop rows and is suitable where plenty of water is available.
- Sprinkler (spray) irrigation sprays water over crops like rainfall; it saves water but is costly and suitable for small areas and low-water crops.
- Drip irrigation is the most efficient method, supplying water directly to plant roots, reducing evaporation, soil erosion and fertilizer wastage.
- Bamboo irrigation, used mainly in Meghalaya, is an eco-friendly traditional-modern method that carries stream water through bamboo pipes in hilly areas.
Key Points: India: A Land of Rivers Yet Water Scarce
- India has many rivers (12 major and 46 medium rivers) but possesses only 4% of the world’s freshwater despite supporting 17% of the world’s population.
- Over-extraction of groundwater has made India the largest user of groundwater in the world, causing wells, tanks and ponds to dry up.
- According to NITI Aayog, more than 600 million people face acute water shortage, and water demand may become twice the available supply by 2030.
- Unequal access to water has increased social burden, especially on women in rural areas, who spend long hours fetching water.
- Rapid population growth, pollution and poor water management have turned water scarcity into a serious national and global crisis.
Important Questions [52]
- Surface Water.
- Differentiate Between Surface Water and Ground Water.
- Which of the following is a ground water source?
- Name Any Two Methods of Water Harvesting in India.
- Give Two Reasons Why Peninsular Rivers Are Not Ideal for Navigation.
- Mention Two Reasons to Explain as to Why We Are Facing Water Scarcity in Most Parts of India.
- Give Two Main Reasons Why Water Scarcity Occurs in India.
- Why is the World in Danger of Facing a Severe Water Shortage in the Coming Future? Give Two Reasons to Support Your Answer.
- State One Measure the Government Should Adopt to Handle the Present Water Crisis.
- Give Three Reasons for the Conservation of Water Resources.
- Name Two States Where Perennial Canals Are Widely Used.
- State a Reason Why the Northern Rivers Are More Suitable for Navigation than the Deccan Rivers.
- State Two Reasons Why Irrigation is Important to a Country like India.
- Name two modern methods of irrigation. State one important reason for their growing popularity.
- Why is well irrigation still a popular means of irrigation? Give two reasons to support your answers.
- State Two Reasons Why Tank Irrigation is Popular in South India.
- Mention Two Advantages that Surface Wells Have Over Inundation Canals.
- Give One Geographical Reason for Each of the Following Statements: Irrigation is Necessary Despite the Monsoon.
- Give One Geographical Reason for Each of the Following Statements: the Drip Method of Irrigation is the Best Among All Modern Methods of Irrigation.
- Give One Geographical Reason for Each of the Following Statements: Canal Irrigation Leads to the Ground Around It Becoming Unproductive.
- Name two states in which tube wells are extensively used. Give a reason to explain its importance as a source of irrigation.
- Briefly Explain Two Reasons for Perennial Canals Being a Popular Form If Irrigation in the Named States
- “The modern means of irrigation are gaining popularity.” Give two reasons to justify this statement.
- Mention Two Factors that Favour the Development of Tube Well Irrigation in Punjab.
- Most of the South Indian States Are Not Suitable for Development of Canal Irrigation.
- There is an Urgent Need for Water Conservation in India.
- Development of Irrigation is Essential for the Growth of the Agriculture Sector of India.
- Inundation Canal.
- Mention Two Factors Which Are Essential for the Development of Tube Well Irrigation.
- Give a Reason Why Traditional Means of Irrigation Are Still Important in Most Parts of India.
- Give a Reason for the Significance of Irrigation In Punjab
- Give a Reason for the Significance of Irrigation In Rajasthan
- Name a State Where Tube Wells Are Common
- Name a State Where Tank Irrigation is Popular
- Sprinkle Irrigation is Practised in Arid and Semi-arid Regions Because of Its High Water Use Efficiency.
- Give One Geographical Reason for Each of the Following: a Tube Well Should Be Installed in a Fertile and Productive Region.
- Give One Geographical Reason for Each of the Following: Canal Irrigation is More Suitable in the Northern Plains.
- “Without Irrigation, Development of Agriculture is Difficult in India”. Clarify the Statement by Giving Two Reasons.
- Name Three Traditional Means of Irrigation.
- Give One Reason for Each of the Following: Tank Irrigation is an Important Method of Irrigation in Karnataka.
- Give a reason for the following: Agriculture sector in India needs the support of irrigation.
- Give a reason for the following: Well irrigation is a popular means of irrigation in Northern India.
- Which means of irrigation can be developed with minimum expenditure?
- Mention one disadvantage of using tank irrigation.
- Mention one advantage of using tank irrigation.
- Where in India is Tank irrigation most widely used?
- Mention one advantage of using tank as a means of irrigation.
- Distinguish Between Inundation Canals and Perennial Canals Or Why Are Perennial Canals More Important than Inundation Canals?
- Give a reason to explain the following: North India has more area under canal irrigation.
- Why is Drip irrigation not practiced on a large scale in India?
- Give one reason for the following: Although expensive, yet, sprinkler irrigation is gaining popularity in recent times.
- What is the advantage of using Drip irrigation?
Concepts [14]
- Sources of Water
- Need to Conserve Water
- Water Conservation Practices > Rainwater Harvesting
- Water Conservation Practices > Watershed Management
- Water Conservation Practices > Rooftop Rainwater Harvesting
- Water Conservation Practices > Recharging Groundwater Aquifers
- Irrigation
- Need for Irrigation
- Means of Irrigation
- Well Irrigation
- Tank Irrigation
- Canal Irrigation
- Modern Irrigation Methods
- India: A Land of Rivers Yet Water Scarce
