Water Resources Of India

Water Resources Of India

water resources in India, including rivers, lakes, oceans, and underground aquifers, are under stress in many regions. Humans need water for drinking, sanitation, agriculture, and industry; and contaminated water can spread illnesses and disease vectors, so clean water is both an environmental and a public health issue. In this unit, learn how water is distributed around the globe; how it cycles among the oceans, atmosphere, and land; and how human activities are affecting our finite supply of usable water.

Types Of Soil Water(Water Resources Of India)

Three basic types or forms of soil water. 

1. 1. Gravitational water: free water that moves through the soil due to the force of gravity. 
      • Gravitational water is found in the macropores. It moves rapidly out of well drained soil and is not considered to be available to plants. 
      • It can cause upland plants to wilt and die because gravitational water occupies air space, which is necessary to supply oxygen to the roots. 
      • Drains out of the soil in 2-3 days
   2. Capillary water: Water in the micropores, the soil solution. 
      • Most, but not all, of this water is available for plant growth 
      • Capillary water is held in the soil.against the pull of gravity 
        Forces Acting on Capillary Water is held in the soil.against the pull of gravity 
        Forces Acting on Capillary Water.
      • micropores exert more force on water than do macropores 
        Capillary water is held by cohesion (attraction of water molecules to each other) and adhesion (attraction of water molecule to the soil particle). 
      • The amount of water held is a function of the pore size (cross-sectional diameter) and pore space (total volume of all pores) 
      • This means that the tension (measured in bars) is increasing as the soil dries out. 

3. Hygroscopic water: This water forms very thin films around soil particles and is not available to the plant. The water is held so tightly by the soil that it can not be taken up by roots. 

• not held in the pores, but on the particle surface. This means clay will contain much more of this type of water than sands because of surface area differences. 
• Hygroscopic water is held very tightly, by forces of adhesion. this water is not available to the plant. 
• Gravity is always acting to pull water down through the soil profile. However, the force of gravity is counteracted by forces of attraction between water molecules and soil particles and by the attraction of water molecules to each other.

Water Resources Of India

Surface Water(Water Resources Of India)

India’s average annual surface run-off generated by rainfall and snowmelt is estimated to be about 1869 billion cubic meter (BCM). However, it is estimated that only about 690 BCM or 37 per cent of the surface water resources can actually be mobilised. This is because

(i) over 90 per cent of the annual flow of the Himalayas rivers occur over a four month period and

(ii) potential to capture such resources is complicated by limited suitable storage reservoir sites.

Rivers(Water Resources Of India)

In India, rivers have been the lifelines of growth and culture. India is drained by twelve major river systems with a number of smaller rivers and streams. Major river systems in the north are the perennial Himalayan rivers – Ganga, Yamuna, Indus and Brahmaputra. The south has the non-perennial but rain fed Krishna, Godavari, and Cauvery while central India has the Narmada, Mahanadi and Tapti.

The Ganges-Brahmaputra and the Indus systems are the largest as they drain almost half of the country carrying more than 40% of the utilisable surface water from the Himalayan watershed to the ocean. Over 70% of India’s rivers drain into the Bay of Bengal, mostly as part of the Ganges-Brahmaputra system. The Arabian Sea receives 20% of the total drainage from the Indus and other rivers. The remaining 10% drains into interior basins and natural lakes.

Lakes(Water Resources Of India)

Apart from rivers, India is house to some of the most beautiful lakes of the world, some natural, others artificial. They are there in the high Himalayas under the ice sheath, in the virgin northeast, semi-arid deserts of Rajasthan, coastal zones, or in metros, small towns and villages.

In India, lakes serve as source of water for drinking, agriculture, and even industries. It acts as sewage absorbers, flood cushions and recharge zones for groundwater aquifers. It is an ecosystem where a variety of birds and animals breed; pisciculture, and aquaculture thrive leading to a source of income for people. Lake tourism is an immensely profiting sector. In India, there are urban and rural lakes along with natural water bodies which have been categorized under the Ramsar Convention on Wetlands (1971) and are important mostly from ecological sustenance and as a source of livelihood for many people.

Rainfall(Water Resources Of India)

The average annual rainfall in India is about 1170 mm. This is considerable variation in rain both temporarily and spatially. Most rain falls in the monsoon season (June-September), necessitating the creation of large storages for maximum utilisation of the surface run-off. Within any given year, it is possible to have both situations of drought and of floods in the same region. Regional varieties are also extreme, ranging from a low value of 100 mm in Western Rajasthan to over 11,000 mm in Meghalaya in North-Eastern India. Possible changes in rainfall patterns in the
coming decade, global warming and climate change and other predicted or observed long-term trends on water availability could affect India’s water resources.

Ground Water(Water Resources Of India)

India’s rechargeable annual groundwater potential has been assessed at around 431 BCM in aggregate terms. On an all India basis it is estimated that about 30 per cent of the groundwater potential has been tapped for irrigation and domestic use. The regional situation is very much different and large parts of India have already exploited almost all of their dynamic recharge. Haryana and Punjab have exploited about 94 per cent of their groundwater resources. Areas with depleting groundwater tables are found in Rajasthan, Gujarat, most of western Uttar Pradesh and in all of the Deccan states. Occurrence of water availability at about 1000 cubic meters per capita per annum is a commonly threshold for water indicating scarcity (UNDP). Investment to capture additional surface run-off will become increasingly more difficult and expensive in the future. Over time, both for surface and groundwater resources, a situation where resources were substantially under utilised and where considerable development potential existed, has transformed in little more than a generation to a situation of water scarcity and limited development options.