Water Resource Availability & Irrigation Potential Notes

Last reviewed 1 Oct 2026 · Facts as of 1 Oct 2026 · 9 min read

NoteDated figures

Water statistics are revised in each assessment. The values below are rounded reference points with their source and year or are described qualitatively for Odisha. Check the latest Central Water Commission (CWC) "Water and Related Statistics", CGWB groundwater resource assessment, and the Odisha Water Resources Department reports before quoting.

Water resources of India

The national water budget

FormulaReference points

Average annual rainfall over the country about 1,170 mm, giving a precipitation volume of about 4,000 billion cubic metres (BCM) (CWC; a long-standing figure).
Average annual water resource potential (surface runoff + replenishable groundwater): about 1,999 BCM (CWC reassessment, 2019); earlier estimates were about 1,869 BCM.
Utilisable water resources: about 1,120 BCM (about 690 BCM surface + about 430 BCM groundwater — rounded; verify); the rest cannot be utilised because of topography, geology and the distribution of rainfall in time and space.

Aspect	Notes
Rainfall	About 75 % of rain falls in the four monsoon months (June–September); large variation across regions and years
Per-capita availability	Fell from about 5,200 m³ per person per year (1951) to roughly 1,500 m³ in the 2010s–2020s (about 1,545 m³ in 2011; verify the latest value); below 1,700 m³ is "water-stressed", below 1,000 m³ is "water scarce" (the Falkenmark indicators)
Surface water	Rivers (Ganga–Brahmaputra–Meghna system holds about 60 % of the flow), reservoirs and tanks
Groundwater	Replenished by rainfall and canal seepage; the largest source for irrigation
Water use	Agriculture uses the major share of withdrawals (commonly stated as about 80–85 % or higher — verify the year and source)

Groundwater assessment (CGWB)

The Central Ground Water Board (CGWB), with the states, estimates annually replenishable ("dynamic") groundwater resources, the extractable resource, extraction, and the "stage of extraction":

Stage of extraction = \frac{annual groundwater extraction}{annual extractable groundwater resource} \times 100

Categories of assessment units (block/mandal/taluka): Safe (below 70 %), Semi-critical (70–90 %), Critical (90–100 %), Over-exploited (above 100 %), plus saline areas.
National stage of extraction: about 60 % in the CGWB assessments for 2022 and 2023 (verify the latest), with severe over-exploitation in Punjab, Haryana, Rajasthan, Delhi and parts of Tamil Nadu and Gujarat, and low stages in the north-east and eastern states.

Worked ExampleExample — stage of extraction (hypothetical block)

A block has an annual extractable groundwater resource of 80 million cubic metres (MCM) and an annual extraction of 62 MCM.

Stage of extraction $= \frac{62}{80} \times 100 = 77.5 %$ — "semi-critical" (70–90 %).

Irrigation terms

DefinitionTerms

Gross Command Area (GCA): the total area bounded by the project's irrigation channels, including unirrigable land.
Culturable Command Area (CCA): the area within the GCA that is fit for cultivation (excludes land not culturable such as buildings, rocks).
Irrigable Command Area (ICA, in some usage): the part of the CCA that the project can irrigate with the water available.
Ultimate irrigation potential (UIP): the maximum area that can be irrigated from all sources, taking all available water.
Irrigation potential created (IPC): the area for which the facilities (canals, wells, pumps) have been built, counting multiple crops separately.
Irrigation potential utilised (IPU): the area actually irrigated in a year; the gap between IPC and IPU (a typical shortfall of 10–20 % or more) shows underuse (poor distribution, silting, lack of field channels, seepage, tail-end problems).
Net irrigated area (NIA): the area irrigated once during the year, regardless of the number of crops; Gross irrigated area (GIA): the area irrigated counted once for each crop.
Irrigation intensity $= \frac{G I A}{N I A} \times 100$ ; percentage of net sown area irrigated $= \frac{N I A}{N S A} \times 100$ .

Classification of irrigation projects (by culturable command area)

Class	CCA
Major	More than 10,000 ha
Medium	2,000 to 10,000 ha
Minor	Up to 2,000 ha (including minor surface (tanks, diversion structures, lift) and groundwater schemes)

Ultimate irrigation potential of India

Sector	Potential (Mha)
Major and medium irrigation (surface)	About 58.5
Minor irrigation — surface water	About 17.4
Minor irrigation — groundwater	About 64.1
Total ultimate irrigation potential	About 140 Mha

(Rounded; the standard figures from the Planning Commission/CWC documents.) The country's net sown area is about 140 Mha, so the UIP is essentially equal to the net sown area but, with multiple cropping, the irrigated gross area can be larger.

Net irrigated area by source (India)

Groundwater (tube wells and other wells) supplies the largest share — roughly three-fifths of the net irrigated area — followed by canals (about one-quarter), with tanks and other sources much smaller (verify the year).
A little over half of the net sown area is irrigated nationally (verify); the rest is rain-fed, so monsoon variation strongly affects output.

Worked ExampleExample — irrigation indicators (hypothetical state)

A state has NSA 6.0 Mha, GCA 8.4 Mha, NIA 3.0 Mha and GIA 4.2 Mha.

Percentage of NSA irrigated $= \frac{3.0}{6.0} \times 100 = 50 %$ .
Irrigation intensity $= \frac{4.2}{3.0} \times 100 = 140 %$ .
Cropping intensity $= \frac{8.4}{6.0} \times 100 = 140 %$ .
If the potential created is 3.6 Mha and the potential utilised is 3.0 Mha, the utilisation ratio is $\frac{3.0}{3.6} = 83 %$ , a gap of 0.6 Mha.

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