Water Resources Class 12 Notes Geography Chapter 6 - CBSE
Chapter : 6
What Are Water Resources ?
- Water is a cyclic resource with abundant supplies on the globe. Approximately, 71% of the earth’s surface is covered with it but freshwater constitutes only about 3% of the total water.
- The assessment, efficient use, and conservation of water are necessary to ensure the development of mankind.
- India accounts for about 2.45% of the world’s surface area, 4% of the world’s water resources and the total utilizable water resource in the country is only 1,122 cubic km.
- There are four major sources of surface water. These are rivers, lakes, ponds and tanks.
- Water flow in a river depends on the size of its catchment area or river basin and rainfall within its catchment area.
- Much of the annual water flow in south Indian rivers like the Godavari, the Krishna, and the Kaveri.
- The groundwater utilization is very high in the states of Punjab, Haryana, Rajasthan, and Tamil Nadu.
- India has a vast coastline and the coast is very indented in some states. Due to this, a number of lagoons and lakes have formed.
- Development of irrigation to increase agricultural production has been assigned a very high priority in the Five-Year Plans and multipurpose river valleys projects.
- Agriculture accounts for most of the surface and groundwater utilization, it accounts for 89% of the surface water and 92% of the groundwater utilization.
- In agriculture, water is mainly used for irrigation as it is difficult to practice agriculture without assured irrigation during dry seasons and in drought-prone areas.
- Irrigated lands have higher agricultural productivity than unirrigated land. In Punjab, Haryana, and western Uttar Pradesh, more than 85% of their net sown area is under irrigation. Wheat and rice are grown mainly with the help of irrigation in these states.
- The over-use of groundwater resources has led to the decline in groundwater tables in Punjab, Haryana, Rajasthan, and Maharashtra.
- The available water resources are getting polluted with industrial, agricultural, and domestic effluents, which is limiting the availability of usable water resources.
- Water gets polluted by foreign matters, such as micro-organisms, chemicals, industrial and other wastes. Such matters deteriorate the quality of water and render it unfit for human use.
- Ganga and the Yamuna are the two highly polluted rivers in the country.
- There is a need to encourage watershed development, rainwater harvesting, water recycling and reuse, and conjunctive use of water for sustainable water supply in long run.
- In plains, river water is used intensively for irrigation, drinking, domestic and industrial purposes. The drains carrying agricultural (fertilizers and insecticides), domestic (solid and liquid wastes), and industrial effluents join the rivers.
- Groundwater pollution has occurred due to high concentrations of heavy/toxic metals, fluoride, and nitrates in different parts of the country.
- We can improve fresh water availability by recycle and reuse of water. Water after bathing and washing utensils can be used for gardening. Water used for washing vehicle can also be used for gardening. This would conserve better quality of water for drinking purposes.
- Watershed management basically refers to the efficient management and conservation of surface and groundwater resources. The success of watershed development largely depends upon community participation.
- The Central and State Governments have initiated many watershed development and management programs in the country, such as Haryali, Neeru-Meeru, and Arvary Pani Sansad.
- Watershed development projects in some areas have been successful in rejuvenating the environment and economy.
- Rainwater harvesting is a method to capture and store rainwater for various uses. It is a low-cost and eco-friendly technique for preserving every drop of water by guiding the rainwater to borewells, pits, and wells.
- Traditional rainwater harvesting in rural areas is done by using surface storage bodies, like lakes, ponds, irrigation tanks, etc.
- There is a wide scope to use rainwater harvesting techniques to conserve precious water resources. It can be done by harvesting rainwater on rooftops and open spaces.
- The issue of desalinization of water particularly in coastal areas and brackish water in arid and semi-arid areas, transfer of water from water surplus areas to water deficit areas through inter-linking of rivers can be important remedies for solving water problem in India.