WATER RESOURCES

Water facts

96.5% of the total volume of the world’s water is in oceans and only 2.5% is freshwater. 70% of this freshwater is in the form of ice. The remaining 30 % is stored in the ground. India receives only 4 % of the global precipitation. By 2025 India will face absolute water scarcity. 

1. Water scarcity and the need for Water Conservation and Management

Water scarcity is caused by overexploitation, excessive use and unequal access among different social groups. Indian rivers are turned into toxic streams Ganga and Yamuna are far away from being pure. The mixing of wastes from increased population, urbanization and industrialization, and agricultural modernization.

Hydraulic structures in ancient India

• In the first century B.C., a sophisticated water harvesting system ‘sringaverapura’ channelled the flood water of River Ganga.
• Under the rule of Chandragupta Maurya, dams, lakes and irrigation systems were extensively built.
• Evidences of sophisticated irrigation works found in Kalinga, [odisha], Nagarjunakonda [Andhra Pradesh], Bennur [Karnataka], Kolhapur [Maharashtra] etc.
• Bhopal Lake in the 11^th century was one of the largest artificial lakes when it was built.
• Hauz Khas tank was built in the 14^th century by lltutmish to supply water to the Siri Fort area.

Dams

• Dams were constructed across the rivers to control floods.
• Later, the stored water was supplied for domestic and industrial purposes; irrigating agricultural fields, electricity generation and inland waterways. Examples are the Bhakranangal project, the Hirakud project etc.
• These multipurpose projects cause damage to the environment and large-scale displacement of the local communities.
• The Narmada Bachao Andolan or Save Narmada Movement is against the construction of the Sardar Sarovar Dam.
• It creates a social gap between landowners and the landless poor.
• Dams create disputes between people and Sabarmati basin farmers because of the high priority given to the urban areas.
• Interstate disputes are quite common.
• Most of the dams are unsuccessful in controlling floods at the time of excessive rainfall.

Rainwater Harvesting

• It was widely used by the ancient Indian people according to their needs.
• People built diversion channels like Guys or rules of the western Himalayas for agriculture.
• Rooftop water harvesting was commonly practised in Rajasthan, Shilling, and Meghalaya, to store drinking water.
• Tamil Nadu is the first state in India that has made a rooftop rainwater harvesting structure compulsory for all. There is a legal provision to punish the defaulters.

Bamboo Drip Irrigation System

 It is a 200-year-old tapping stream and spring water using bamboo pipes in Meghalaya.18-20 litres of water enter into the bamboo pipe system, is transported over hundreds of meters, and finally reduces to 20-80 drops per minute at the site of the plant.