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Water Resources

• We need water for drinking, cooking, washing, coolant in machines, electricity (hydel power plant),  product manufacturing drinking products.
• We obtain water from various sources such as river, springs, lakes, ponds, oases.

Water is a renewable resource

• Hydrological Cycle – Water passes through different phases in its life cycle . Due to Sun rays water from ocean rivers and other sources get evaporated . Since the evaporated water is lighter than the atmospheric air. hence it get lifted up. in atmosphere water vapours comes together and forms clouds these clouds are transferred by wind in various places . water then comes to the earth in the form of rain and snow which then gathered in various water sources such as ocean , rivers ,etc. This cycle continues called Hydrological cycle.

Water Scarcity and the need for Water Conservation and Management
Reason for bad quality of water :
1.Urbanisation and industrialisation
2.Chemicals
3.Pesticides and fertilisers used in agriculture
4.Population growth
5.Domestic and industrial wastes
Need of Water Conservation and Management :
1.To protect ourselves from health hazards.
2.To protect our basic needs for food, continuation of our livelihoods and productive activities
3.To prevent degradation of our natural ecosystems.
4.To prevent ecological crisis
5.To prevent over-exploitation and mismanagement of water resources,which in turn prevents
  water scarcity.
Reasons for Water Scarcity:

• Seasonal Rainfall
• Growing Population
• Over-Exploitation
• Industrialisation
• Urbanisation
• Water Pollution

Multipurpose river project -Dams

• A dam is a reservoir created to obstruct the way of river water so that water can be stored at one place.
• This stored water can be used for
• Irrigation
• Electricity generation
• Water supply for domestic and industrial use
• Recreation
• Inland navigation
• Fish breeding

Since dams are used for these multiple purposes hence these are called multipurpose river projects.

• Examples of such projects are Bhakra-Nangal project in Sutlej-Beas river basin. Hirakud project in Mahanadi basin.

Advantages of Multipurpose river projects

• Beside the main functions there are various advantages of Dams these are
• Commercial Farming: Since plenty of water is available farmers can now take commercial crops that requires large amount of water.
• Removal of Salinity: Accumulation of salts in soil is called salinisation. It causes poor growth of crop. This  condition can be removed by irrigating large amount of water such that salts go deep in the soil out of reach from roots.

Disadvantages of Dam Multipurpose river projects:

• Even if these projects are very helpful still these are opposed due to various reasons such as
• Poor Aquatic Habitat – Sediments are the particulate matter that move this along river . It accumulate over aquatic plant in the dam and hence spoil living conditions of aquatic life.
• Riverwater carry particulate matter at the bottom called as sediment. Building a dam obstructs the way of sediment flow and thus it get accumulated at the bottom in the dam. due to which useful soil and thus aquatic plants get buried under the rockier surface resulting into their decomposition. Hence dams causes poorer living conditions for aquatic life.
• Sediments are particulate matter that moves along river. It accumulate over aquatic plants in the dam and hence spoil living conditions of aquatic life.
• Reduction of water capacity: Over time the rockier layer increases and thus reduces the capacity of the water.
• Not Beneficial to all: With these projects rich landowners, large farmers, industrialists and some urban areas get benefited but on the other hand poor peoples have to sacrifice their land and resources. Hence these projects are opposed through movements like ‘Narmada Bachao Andolan’ and ‘Tehri Dam Andolan.’
• Increases social Gap: With plenty of available water rich such as industrialists, landowners become richer and poor live as it is, this lead to increases in social gap.
• Conflicting Demands: Different people’s need water for different purposes. Hence these conflicting demands can cause violent conditions in the society. Also on political sense it becomes inter-state disputes

Rainwater Harvesting Techniques

• Guls or Kuls: The diversion channels built in hilly areas for irrigation is called guls or kuls.
• Rooftop Rainwater Harvesting: Rainwater from roof is transferred through pipe to underground tanks or wells.
• Inundation Channels: These are the canals from large rivers around the farm. During flooding these canals get filled and hence supply water to the farm.
• Khadins and Johads: In the low rainfall regions rainwater is stored in storage structures in the agricultural fields and used for irrigation.
• Underground Tanks or Tankas: Most of the houses in Rajasthan has underground tanks or tanks that are usually big rooms. During rainy season these collect water using rooftop water harvesting system and store it for drinking and daily water needs.