Irrigation in Nepal: Coverage, Surface vs Groundwater, Provinces

Nepal has 3,557,764 hectares of agricultural land, of which 2,536,319 hectares — about 71 percent — is classed as potentially irrigable, according to the Irrigation Master Plan 2019 (Updated 2024) prepared by the Department of Water Resources and Irrigation (DWRI). Irrigation infrastructure of all kinds commands a gross area of about 1,435,302 hectares. That equals roughly 40 percent of all agricultural land and about 57 percent of the irrigable area. The Ministry of Energy, Water Resources and Irrigation reported a slightly higher figure of 44.63 percent of agricultural land with access to irrigation facilities as of mid-March 2024 (Falgun 2080 BS), reflecting schemes completed after the master-plan inventory.

Household-level data tell a similar story. The National Sample Census of Agriculture 2021/22 (2078/79 BS), conducted by the National Statistics Office, found that 54.5 percent of the land operated by farm holdings — about 1.21 million of 2.22 million hectares — was irrigated, and that 2.89 million holdings, or 70 percent of all 4.13 million holdings, used some form of irrigation. The irrigated share of holdings' land rose by only about 2.5 percentage points over the preceding decade.

The different percentages are not contradictions; they measure different things. 'Command area' counts land that infrastructure is designed to serve (gross 1,435,302 ha; net cultivable command about 1,076,477 ha), while the census counts land farmers actually reported irrigating within their holdings, and ministry coverage figures track equipped area against total agricultural land. For exams and research, always note which definition a source uses. For comparison, the Food and Agriculture Organization's AQUASTAT database recorded 1,168,349 hectares equipped for irrigation based on the 2001/02 agricultural census.

Nepali farmers have built and run gravity canals (kulo) for centuries, and farmer-managed systems still dominate by number. State-built 'modern' irrigation began with the Chandra Canal (Chandra Nahar) in Saptari district, constructed in 1922–1928 AD (1979–1985 BS) from the Triyuga River with a command area of about 10,000 hectares — the first modern irrigation system in Nepal.

Today the DWRI inventory groups irrigation into four broad types. Agency-managed irrigation systems (AMIS) are large canal networks built and operated by the government, mainly in the Terai. Farmer-managed irrigation systems (FMIS) are community-run canals, most numerous in the hills. Groundwater irrigation relies on shallow and deep tubewells, overwhelmingly in the Terai. Non-conventional systems cover ponds, tanks, drip, sprinkler and lift schemes, mostly in the hills and mountains. In addition, an estimated 12,000 very small community schemes covering up to 150,000 hectares operate outside the main inventory.

Of the 1,435,302 gross hectares commanded by irrigation infrastructure, surface-water systems (agency and farmer-managed canals combined) account for 928,658 hectares, or about 65 percent. Groundwater irrigation covers 493,830 hectares — roughly one-third of the total — and non-conventional systems about 12,814 hectares, under 1 percent. In net terms the split is 696,494 hectares surface, 370,373 hectares groundwater and 9,611 hectares non-conventional, for a net irrigated area of 1,076,477 hectares.

Nepal is water-rich on paper but water-poor in the dry season. The master plan estimates annual surface-water availability at 172,900 million cubic metres (at 80 percent reliability) plus about 13,215 million cubic metres of annually replenishable groundwater — enough in total to irrigate 6.9 million hectares, nearly three times the irrigable land. However, based on lean-season (March) river flows, dry-season surface irrigation potential is only about 0.75 million hectares. This is why the plan prioritises storage dams, inter-basin transfer projects and groundwater development over new run-of-river canals alone.

Groundwater irrigation in Nepal is almost entirely a Terai phenomenon, drawing on the thick alluvial aquifers of the Gangetic plain. The DWRI inventory counts 152,766 shallow tubewells irrigating 444,841 hectares and 1,278 deep tubewells irrigating 48,989 hectares nationwide. Of these, 149,521 shallow and 1,250 deep tubewells are in the Terai; the hills have only about 3,273 tubewells on some 7,953 hectares. Shallow tubewells are typically drilled to about 50 metres and run by individual farmers or small groups with portable diesel or electric pumpsets, while deep tubewells are larger community or agency-built installations.

Because aquifers do not dry up seasonally the way rivers do, groundwater is effectively year-round irrigation, and the master plan treats it as such. The Groundwater Resources Development Board (GWRDB) investigates and licenses development, and recent programmes — including solar-powered pumping promoted by the government and development partners — aim to cut diesel costs that have historically limited pumping in the dry season. Localised concerns about falling water tables in parts of the eastern and central Terai are prompting calls for recharge management and monitoring.

Headline coverage numbers hide the most important weakness of irrigation in Nepal: seasonality. The Irrigation Master Plan estimated that only about 39 percent of irrigated land received year-round irrigation as of 2020; the rest is served mainly during the monsoon (roughly June–September), when rivers are full but rain is abundant anyway. National cropping intensity on irrigated land was about 132 percent, far below the 200-percent-plus achievable with reliable dry-season water.

The agriculture census paints a rosier self-reported picture — holders said 72.7 percent of their irrigated land was 'irrigable throughout the year' — but this reflects farmers' judgment of possibility rather than measured reliable supply, and includes supplementary sources. The gap between monsoon and winter–spring service is the reason wheat and spring paddy areas remain vulnerable to drought even inside canal commands.

Closing this gap is the central goal of national policy. The Agriculture Development Strategy (ADS, 2015) targeted year-round irrigation on 60 percent of irrigated land by 2025 and 80 percent by 2030; the Irrigation Master Plan 2019 (Updated 2024) extends the target to 100 percent by 2045, alongside raising cropping intensity from 132 percent to 182 percent (2025), 205 percent (2030) and 230 percent (2045).

Geography dictates where irrigation works. The Terai, with flat land and deep aquifers, holds 1,171,374 gross hectares — about 81 percent of Nepal's irrigated area — while the hills hold 213,148 hectares (about 15 percent) and the mountains 50,779 hectares (about 4 percent). The master plan aims to eventually irrigate 100 percent of the Terai's 1.499 million irrigable hectares and has identified a further 566,000 hectares in the hills and mountains for gravity, pump, tank and solar-lift development.

Comprehensive official irrigated-area totals are still published by ecological zone rather than by province, but DWRI's Nepal Irrigation Management Information System (NIMIS) provides a live province-wise inventory of farmer-managed irrigation systems, which serve roughly 70 percent of the country's irrigated area. As accessed in 2026, NIMIS records 6,040 FMIS with a gross command area of about 668,677 hectares, distributed as below.

The agriculture census adds a useful provincial contrast: 94.8 percent of farm-holding land in Madhesh Province is wet land (khet), against just 27.6 percent in mountainous Karnali Province — the widest irrigation-readiness gradient in the country. Madhesh, Lumbini, Koshi and Sudurpashchim, with large Terai shares, dominate both canal commands and tubewell numbers, while Bagmati leads in the number of small hill FMIS.

The largest operating canal network is the Sunsari–Morang Irrigation System in the eastern Terai, commanding about 68,000 hectares from the Koshi River. Other major agency systems include Bagmati (Sarlahi/Rautahat), Sikta (Banke), Babai (Bardiya), Rani–Jamara–Kulariya (Kailali) and the Mahakali schemes (Kanchanpur). The Bheri–Babai Diversion Multipurpose Project, a 'national pride' project whose 12-kilometre tunnel broke through in 2019 (2075 BS), is designed to provide year-round water to about 51,000 hectares in Banke and Bardiya while generating hydropower; the Sunkoshi–Marin diversion, whose tunnel broke through in 2024 (2080 BS), will feed the Bagmati command to irrigate about 122,000 hectares in Madhesh.

For the next generation, the Irrigation Master Plan ranks inter-basin transfer and storage projects — Tamor–Morang, Sunkoshi Marin plus Kamala with the Sunkoshi-3 dam, Kaligandaki–Tinau, Naumure/Rapti, Kapilbastu diversion, Karnali transfer to Kailali and the Chatara Barrage — with an estimated capital investment of USD 9,823 million over 25 years for the priority set. Because these dams store monsoon water for winter release, they are the main instrument for converting seasonal commands into year-round irrigation.

At the federal level, irrigation sits under the Ministry of Energy, Water Resources and Irrigation (MoEWRI) and its Department of Water Resources and Irrigation (DWRI), created in the post-2015-constitution restructuring by merging the former Department of Irrigation with water-induced disaster management functions. Under federalism, large, technically complex and cross-province projects remain federal; provincial Ministries of Physical Infrastructure Development (MoPID) handle projects within one province; and local governments manage small schemes. Water users' associations (WUAs) operate transferred and farmer-managed systems, a management-transfer policy Nepal has followed since the 1980s.

The guiding sector document is the Irrigation Master Plan 2019 (Updated 2024), a 25-year plan running to 2044/45 (2101 BS) that sets the coverage, modernisation and year-round targets described above. Its goals include near-full (90 percent) development of irrigable land, full management transfer of agency systems, raising system efficiency above 50 percent and lifting irrigation service-fee collection to 75 percent. Progress data are consolidated in DWRI's NIMIS database, the best public entry point for scheme-level irrigation statistics in Nepal.