Water is a critical natural resource essential for human survival, agriculture, industry, and ecological balance. India faces significant challenges regarding water availability, quality, and management due to population growth and industrial expansion.
Demand for Water
Water demand in India is broadly categorized into three main sectors:
1. Agricultural Sector
Agriculture is the largest consumer of water in India, accounting for nearly 80% to 90% of total freshwater extraction. High crop irrigation requirements, coupled with water-intensive crops such as paddy and sugarcane, drive this excessive demand.
2. Industrial Sector
Rapid industrialization increases water requirements for cooling, manufacturing processes, chemical operations, and waste disposal. Key water-intensive industries include thermal power plants, textiles, paper, and metallurgy.
3. Domestic Sector
Domestic demand includes water required for drinking, cooking, sanitation, cleaning, and municipal services. Urbanization, rising living standards, and population growth are steadily accelerating domestic water demand.
Overuse and Depletion of Surface and Ground Water Resources
Depletion of Surface Water Resources
Surface water sources include rivers, lakes, reservoirs, and streams. Over-extraction for irrigation, damming, pollution from untreated industrial effluents, and sewage discharge have depleted surface water levels and severely degraded aquatic ecosystems.
Depletion of Groundwater Resources
Groundwater is heavily exploited via tube wells and borewells for agricultural and domestic needs. When the rate of extraction exceeds the natural replenishment rate (aquifer recharge), severe groundwater depletion occurs.
- Lowering of Water Tables: Farmers must dig deeper wells to reach water.
- Saltwater Intrusion: Excessive pumping in coastal zones causes seawater to infiltrate freshwater aquifers.
- Land Subsidence: Compaction of soil layers following water removal leads to land sinking.
Water Quality Standards in India
The Bureau of Indian Standards (BIS) prescribes drinking water standards under IS 10500:2012 to ensure public safety.
| Parameter | Acceptable Limit | Permissible Limit (in absence of alternate source) |
|---|---|---|
| pH Value | 6.5 to 8.5 | No relaxation |
| Total Dissolved Solids (TDS) | 500 mg/L | 2000 mg/L |
| Turbidity | 1 NTU | 5 NTU |
| Nitrate (as NO3) | 45 mg/L | No relaxation |
| Fluoride | 1.0 mg/L | 1.5 mg/L |
| Total Hardness (as CaCO3) | 200 mg/L | 600 mg/L |
Wetlands
Definition of a Wetland
A wetland is an area of land whose soil is saturated with moisture either permanently or seasonally. According to the Ramsar Convention, wetlands are areas of marsh, fen, peatland or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or salt, including areas of marine water the depth of which at low tide does not exceed six meters.
Types of Wetlands
| Category | Sub-types | Key Features |
|---|---|---|
| Freshwater Wetlands | Riverine (rivers, streams), Lacustrine (lakes, reservoirs), Palustrine (marshes, bogs, swamps) | Low salt concentration; dependent on precipitation, runoff, or groundwater discharge. |
| Marine and Coastal Wetlands | Estuaries, mangroves, coral reefs, lagoons, salt marshes | High or variable salinity; strongly influenced by oceanic tides and coastal currents. |
Ecological Significance of Wetlands
- Biodiversity Hotspots: Provide crucial habitats, nesting sites, and feeding grounds for resident and migratory bird species, amphibians, and aquatic organisms.
- Water Purification: Act as natural filters by trapping sediments, heavy metals, and excess nutrients.
- Flood Mitigation: Function as natural sponges, absorbing excess storm water and reducing flood peaks downstream.
- Groundwater Recharge: Facilitate the slow infiltration of surface water into underground aquifers.
- Carbon Sequestration: Store vast amounts of organic carbon, aiding in climate change mitigation.
Threats to Wetlands
- Encroachment: Conversion of wetland areas for agriculture, housing, and industrial development.
- Pollution: Agricultural runoff loaded with fertilizers and pesticides, untreated industrial waste, and sewage leading to eutrophication.
- Hydrological Alterations: Construction of dams, dykes, and canalization that disrupt natural water flow.
- Biological Invasions: Spread of invasive plant species like Water Hyacinth (Eichhornia crassipes), which choke water bodies and reduce dissolved oxygen levels.
Ramsar Convention, 1971
The Ramsar Convention on Wetlands of International Importance is an intergovernmental environmental treaty established in 1971 in Ramsar, Iran, providing the framework for national action and international cooperation for the conservation and wise use of wetlands.
- Wise Use Principle: Sustainable utilization of wetlands for human benefit while maintaining ecosystem integrity.
- Montreux Record: A register of Ramsar wetland sites where changes in ecological character have occurred, are occurring, or are likely to occur as a result of technological developments, pollution, or human interference.
Major Wetlands and Wetland Resources of North East India
North East India is rich in freshwater ecosystems due to high rainfall and extensive river systems, serving vital socio-economic and ecological functions.
| Wetland Name | State | Ecological Importance & Key Characteristics |
|---|---|---|
| Loktak Lake | Manipur | Largest freshwater lake in NE India; famous for floating vegetation masses called phumdis and home to the endangered Sangai deer (Rucervus eldii eldii) in Keibul Lamjao National Park; Ramsar site. |
| Deepor Beel | Assam | A permanent freshwater lake and riverine wetland in the Brahmaputra valley; essential staging site for migratory birds and habitat for Asian elephants; Ramsar site. |
| Rudrasagar Lake | Tripura | A natural sedimentation reservoir fed by three streams; supports significant freshwater biodiversity and fisheries; Ramsar site. |
| Palak Dil (Palak Lake) | Mizoram | Largest natural lake in Mizoram, surrounded by tropical evergreen forests, sustaining rich avian and aquatic fauna. |
Key Resources Provided by North East Wetlands:
- Fisheries: Provide primary livelihoods and protein sources for local communities.
- Bio-resources: Yield aquatic plants, wild edible flora, medicinal species, and raw materials for traditional crafts.
- Flood Moderation: Act as natural flood retention basins during peak monsoon overflows in the Brahmaputra and Barak river basins.