Water management
- Introduction
- Water is one of the most essential natural resources for sustaining life, agriculture, and ecosystem balance. Efficient water management is crucial for ensuring adequate supply for agriculture, industries, domestic use, and maintaining environmental sustainability.
- Agriculture is the largest consumer of water globally — using nearly 70% of all freshwater withdrawals, making efficient management a key factor for food and water security.
- Meaning of Water Management
Water management refers to the planning, development, distribution, and optimum use of water resources for agriculture, domestic, industrial, and environmental purposes.
It involves:
- Conservation of water resources,
- Efficient irrigation practices,
- Harvesting and recycling of water, and
- Maintaining water quality and sustainability.
Objective: To ensure judicious use of water resources so that present and future needs can be met without causing ecological imbalance.
- Global Water Resources
3.1 Total Water on Earth
- Total water available on Earth: ~1,386 million cubic kilometers (M km³).
- Distribution of global water resources:
|
Source |
Percentage of Total Water |
Remarks |
|
Oceans (saline water) |
~97.5% |
Not usable for irrigation/drinking |
|
Freshwater |
~2.5% |
Only source for human and agricultural use |
|
— Glaciers and ice caps |
~68.7% of freshwater |
Locked, unavailable |
|
— Groundwater |
~30.1% of freshwater |
Major usable reserve |
|
— Surface water & atmosphere |
~0.3% of freshwater |
Lakes, rivers, soil moisture |
Usable freshwater = Less than 1% of total global water.
3.2 Global Water Distribution by Continent
|
Continent |
Share of Renewable Water Resources (%) |
Major River Basins |
|
Asia |
~36% |
Ganges, Yangtze, Mekong, Indus |
|
South America |
~26% |
Amazon, Orinoco |
|
North America |
~15% |
Mississippi, St. Lawrence |
|
Europe |
~8% |
Volga, Danube |
|
Africa |
~9% |
Nile, Congo, Niger |
|
Australia & Oceania |
~6% |
Murray–Darling, Fitzroy |
- Water Resources in India
4.1 Overview
India accounts for ~4% of the world’s freshwater resources but supports ~18% of the global population.
Hence, India faces severe pressure on water resources.
Total annual precipitation (rainfall + snowfall): ~4,000 billion cubic meters (BCM)
Usable water resources (surface + groundwater): ~1,123 BCM
- Surface water: 690 BCM
- Groundwater: 433 BCM
4.2 Distribution of Water Resources in India
|
Source |
Total Water (BCM) |
Usable (BCM) |
Percentage (%) |
|
Precipitation (rain + snow) |
4,000 |
— |
— |
|
Surface water (rivers, lakes, etc.) |
1,869 |
690 |
61% |
|
Groundwater |
432 |
433 |
39% |
|
Total usable |
— |
1,123 BCM |
100% |
4.3 Major River Basins of India
India has 20 major river basins — the most important include:
|
River Basin |
Catchment Area (sq. km) |
Major Rivers |
|
Ganga |
8,61,000 |
Ganga, Yamuna, Ghaghara |
|
Brahmaputra |
1,94,000 |
Brahmaputra, Barak |
|
Godavari |
3,13,000 |
Godavari |
|
Krishna |
2,59,000 |
Krishna |
|
Narmada |
98,000 |
Narmada |
|
Mahanadi |
1,41,000 |
Mahanadi |
|
Cauvery |
81,000 |
Cauvery |
|
Indus (Indian part) |
3,21,000 |
Sutlej, Beas, Chenab, Ravi, Jhelum |
4.4 Water Use Sector-Wise (India)
|
Sector |
Percentage of Total Water Use |
|
Agriculture |
78–80% |
|
Industry |
8–10% |
|
Domestic |
6–8% |
|
Others (power, environment) |
2–4% |
By 2050, water demand is projected to rise to 1,447 BCM, of which agriculture will account for ~70%.
4.5 Groundwater in India
- India is the largest user of groundwater in the world.
- Accounts for ~25% of global groundwater extraction.
- Overexploitation has led to declining water tables in several states (Punjab, Haryana, Rajasthan, UP, Tamil Nadu).
- Central Ground Water Board (CGWB) monitors and manages groundwater resources.
- Water Resources of Uttar Pradesh (Example of a State)
5.1 Geographical Overview
- Total geographical area: 240.9 lakh ha
- Net irrigated area: ~175 lakh ha
- Average annual rainfall: ~990 mm
- Total renewable water resources: ~249 BCM (surface + groundwater)
5.2 Major River Systems
- Ganga River System: Ganga, Yamuna, Ramganga, Ghaghara, Gomti, and Sone.
- Other Rivers: Betwa, Ken, Chambal, and Gandak.
5.3 Water Availability and Use
|
Type |
Availability (BCM) |
|
Surface Water |
~169 |
|
Groundwater |
~80 |
|
Total |
249 BCM |
5.4 Irrigation Sources in U.P.
|
Source |
Percentage Contribution |
|
Tube wells and wells |
~74% |
|
Canals |
~18% |
|
Tanks and others |
~8% |
- Challenges in Water Management
- Uneven distribution of rainfall and rivers across regions.
- Overexploitation of groundwater resources.
- Low irrigation efficiency (average only 35–40%).
- Waterlogging and salinity in irrigated areas.
- Pollution of surface and groundwater.
- Climate change leading to altered rainfall patterns.
- Conflict among states over river water sharing.
- Strategies for Effective Water Management
- Integrated Water Resources Management (IWRM): Coordinated use of surface and groundwater.
- Rainwater Harvesting: Collection and storage of rainwater for later use.
- Watershed Management: Conservation of soil and water in a defined area.
- Use of Efficient Irrigation Methods: Drip, sprinkler, and subsurface irrigation.
- Adoption of Water-Saving Crops: Drought-tolerant and short-duration varieties.
- Reuse and Recycling: Using treated wastewater for agriculture and landscaping.
- Community Participation: Involvement of Water User Associations (WUAs).
- Policy and Institutional Reforms: Pricing, regulation, and efficient governance.
- Important Facts and Data
- Global freshwater availability: Only 0.5% of total water.
- Per capita water availability (India, 2020): ~1,486 m³/year (Water-stressed condition).
- Projected (2050): <1,000 m³/year — approaching water-scarce condition.
- Major irrigated states: Uttar Pradesh, Punjab, Haryana, Andhra Pradesh, Tamil Nadu.
- Average irrigation efficiency:
- Surface irrigation: 30–40%
- Sprinkler irrigation: 60–70%
- Drip irrigation: 80–90%
