Last reviewed 16 Sept 2026 · Facts as of 16 Sept 2026 · 8 min read
Water resources of India
- Average annual water resource potential of India's river basins: about 1869 BCM (earlier assessment), revised to about 1999 BCM in the Central Water Commission's 2019 reassessment.
- Utilisable surface water has been estimated at about 690 BCM.
- Per-capita water availability: about 1816 m³ (2001) and about 1545 m³ (2011) — it falls as population rises.
- Indicators widely used: per-capita availability below 1700 m³/year indicates water stress; below 1000 m³/year, water scarcity (Falkenmark indicator).
- Rainfall and runoff are highly uneven in space (Brahmaputra and west-flowing Ghat rivers are water-rich; western Rajasthan and Saurashtra are scarce) and time (most runoff in the monsoon months).
National Water Policy
India's National Water Policy was adopted in 1987 and revised in 2002 and 2012. Main principles:
- Water as a scarce, precious national resource to be planned and managed on an integrated basis with the river basin as the unit.
- Priority for drinking water (the 2002 policy's order: drinking water, irrigation, hydropower, ecology, agro- and non-agro-industries, navigation and other uses).
- The 2012 policy emphasises water for basic human needs and ecological flows, treating water as an economic good beyond these, water-use efficiency, water pricing, conjunctive use, groundwater regulation, and adaptation to climate change.
- Participation of users (participatory irrigation management, water users' associations), maintenance of existing infrastructure, data sharing and flood/drought management.
Water resources planning
Objectives
Meeting demands for drinking water, irrigation, industry, hydropower, navigation, recreation and ecology; flood and drought mitigation; economic efficiency, regional development and social equity; environmental sustainability.
Levels and stages
- Levels: national, state/regional, river basin, project.
- Stages: reconnaissance → pre-feasibility → feasibility → detailed project report → implementation → operation and evaluation.
- Data: hydrological, meteorological, topographic, geological, soil, land use, demographic, economic, environmental.
Multipurpose projects
A multipurpose project serves two or more purposes (irrigation, hydropower, flood control, water supply, navigation, fisheries, recreation). Example uses of reservoir storage:
| Use | Reservoir requirement |
|---|---|
| Flood control | Keep reservoir low before and during the flood season (empty flood cushion) |
| Irrigation / water supply | Keep reservoir full at the end of monsoon |
| Hydropower | High head (full reservoir) and regulated releases throughout the year |
| Navigation | Steady minimum releases |
| Recreation / fisheries | Stable levels |
Conflicts: flood control vs conservation storage; hydropower release pattern vs irrigation demand; consumptive uses vs navigation and ecological flows. They are reconciled by zoning storage (dead storage, live/conservation storage, flood cushion) and rule curves for reservoir operation.
Compatible uses: hydropower with navigation and water supply downstream (non-consumptive releases), irrigation with fisheries.
Integrated Water Resources Management (IWRM)
A process that promotes coordinated development and management of water, land and related resources to maximise economic and social welfare equitably without compromising ecosystems. Features: river-basin approach, stakeholder participation, demand management, conjunctive use of surface and groundwater, environmental flows, institutional coordination (river basin organisations).
Economic analysis
- Benefit–cost ratio: — a project is economically justified if .
- Net present value: — justified if .
- Internal rate of return (IRR): discount rate at which — justified if IRR exceeds the opportunity cost of capital.
- Capital recovery factor (annual instalment to repay a present sum over years at rate ):
- Present worth factor (single payment):
Irrigation projects in India have traditionally been evaluated by B/C ratio (with different thresholds for normal and drought-prone areas) and by IRR; intangible and environmental costs should also be assessed.