Major Irrigation Projects of Nepal: A Complete Guide

Irrigation is central to Nepal's economy because farming supports roughly two-thirds of the population, yet most fields still depend on the monsoon. The Department of Water Resources and Irrigation (DWRI), under the Ministry of Energy, Water Resources and Irrigation, plans and builds the country's large public irrigation schemes. Its long-term blueprint is the Irrigation Master Plan 2019 (Updated 2024), approved at ministerial level on 30 May 2024 (2081/02/17 BS).

According to that master plan, Nepal has about 2.5 million hectares of potentially irrigable land, of which roughly 1.5 million hectares already have some irrigation infrastructure. The plan targets year-round irrigation on the full 1.499 million hectares of irrigable Terai land, plus about 566,000 hectares in the Hills and Mountains served by gravity or pumping. The 'major' projects covered here are the large, multi-district schemes that dominate this national effort.

Most of these headline schemes lie in the Terai and Inner Terai, where flat, fertile plains and big perennial rivers make large gravity-fed canals possible. Six irrigation and river-diversion schemes carry the government's National Pride Project (Rastriya Gaurav Ayojana) label, marking them as strategically important and eligible for priority budgeting. This page profiles those flagship projects along with the older Sunsari-Morang system.

Nepal's National Pride Projects are a finite, officially designated set of nation-building schemes. Within that list, six are irrigation or inter-basin water-diversion projects managed through DWRI. They are the clearest reference point for what counts as a 'major' irrigation project, because their status is set by government decision rather than informal reputation.

The six national-priority irrigation and diversion projects, together with the large Sunsari-Morang system that predates the designation, form the backbone of Nepal's surface-irrigation network. Their command areas, river sources and provinces are summarised below.

The Sunsari-Morang Irrigation Project (SMIP) is the country's largest and one of its oldest surface-irrigation systems. It draws water from the Koshi River in eastern Nepal and was originally built with Indian government assistance about five decades ago, following the bilateral Koshi agreement. The scheme spans Sunsari and Morang districts in Koshi Province.

SMIP has a gross command area of roughly 112,000 hectares stretching between the Koshi River in the west and the Bakra River in the east. Its existing net command area is about 68,000 hectares, of which around 40,000 hectares lie in Sunsari district and 28,000 hectares in Morang. Because much of the original infrastructure has aged, large portions of the main and branch canals have needed rehabilitation to prevent collapse and water loss.

Modernisation has been carried out in phases with external support, including the World Bank-financed Second Sunsari-Morang Irrigation Project, which rehabilitated canals and structures and strengthened operation-and-maintenance systems. The aim is to convert an ageing, seasonally unreliable network into an efficient, year-round system while extending benefits to additional land.

The Sikta Irrigation Project sits on the Rapti (West Rapti) River in Banke district, Lumbini Province, where a 317-metre barrage at Agaiya in Rapti Sonari Rural Municipality feeds eastern and western canals. Its design command area is about 42,766 hectares (roughly 33,766 hectares west and 9,000 hectares east of the river). A National Pride Project, Sikta was launched in fiscal year 2062/63 BS (2005/06 AD) using the government's own resources, but it has become a byword for delay: physical progress was only around 42 percent after some 19 years, and the estimated cost has been revised repeatedly from about Rs 7.45 billion to roughly Rs 52.89 billion.

Sikta's troubles include a widely reported canal collapse during testing, contractor disputes, land-acquisition shortfalls and corruption allegations. Even so, sections of the system have begun delivering water to farmers, and completion has been re-scheduled toward the early 2030s (around FY 2032/33). The project illustrates both the promise and the risk of Nepal's large gravity-canal ambitions.

Nearby, the Babai Irrigation Project on the Babai River in Bardiya district is designed to irrigate about 36,000 hectares, split into an eastern command area of roughly 21,000 hectares and a western area of about 15,000 hectares. Construction began back in fiscal year 2045/46 BS (1988/89 AD), yet the scheme remained incomplete decades later, with physical progress reported above 80 percent and cost estimates climbing from about Rs 2.87 billion to nearly Rs 19 billion. It has nonetheless started supplying water to more than 27,000 hectares of farmland.

Two of Nepal's most ambitious projects are inter-basin water-transfer schemes that move water between river basins through long tunnels. The Bheri-Babai Diversion Multipurpose Project (BBDMP) diverts water from the Bheri River into the Babai through a 12.2-kilometre headrace tunnel — the first tunnel in Nepal excavated with a Tunnel Boring Machine (TBM). The TBM broke through in April 2019, roughly six months ahead of schedule, a landmark for Nepali civil engineering. Once fully operational, BBDMP is designed to provide year-round irrigation to about 51,000 hectares in Banke and Bardiya and to generate around 46 MW of hydropower.

The Sunkoshi-Marin Diversion Multipurpose Project (SMDMP) transfers water from the Sunkoshi River in the east into the Marin, a tributary of the Bagmati, through a 13.3-kilometre TBM tunnel — the second and longest such tunnel in the country. Its Robbins double-shield machine achieved breakthrough on 8 May 2024, about 11 months early. By augmenting the existing Bagmati Irrigation System, the project aims to bring additional year-round irrigation to roughly 122,000 hectares across Rautahat, Bara, Sarlahi, Mahottari and Dhanusha in Madhesh Province, and to add about 31 MW of installed hydropower capacity.

Both projects show a clear pattern: the technically demanding tunnel components have been delivered ahead of schedule, but the associated headworks, dams, canals and powerhouses have lagged. For Bheri-Babai, second-phase civil works missed successive deadlines, standing at roughly 57 percent completion in early 2026, while Sunkoshi-Marin's finished tunnel awaited construction of its headworks dam.

The Rani-Jamara-Kulariya Irrigation Project (RJKIP) modernises three historic farmer-managed canal systems in Kailali district, Sudurpaschim Province, taking water from the Karnali River near Chisapani. Originally covering about 11,000 hectares in their traditional form, the systems were re-engineered under a modernisation programme to deliver reliable, year-round irrigation to around 14,300 hectares. The World Bank has financed the work in phases — broadly Phase 1 from 2012 to 2017 and Phase 2 from 2018 to 2025 — and a further phase has been advanced to extend irrigation to additional thousands of hectares.

In the far west, the Mahakali Irrigation Project draws on the Mahakali River, with water released to Nepal from India's Tanakpur Barrage under the terms of the 1996 (2052 BS) Mahakali Treaty. The project has been developed in stages; Stage III is designed to irrigate about 33,520 hectares across parts of Kanchanpur and Kailali districts, including the Dodhara-Chandani, Brahmadev, Tribhuvanbasti and Malakheti areas. The main canal has been built and even test-run, but full water delivery has been held up by cross-border operational issues on the Indian side.

Together, these two schemes anchor irrigation development in Nepal's far-western plains, tying domestic canal-building to trans-boundary rivers shared with India. They also highlight how diplomacy and treaty implementation, not just engineering, shape whether water actually reaches farmers' fields.

A recurring theme across Nepal's major irrigation projects is chronic delay and ballooning cost. Schemes such as Babai and Sikta have run for decades past their original timelines, with budgets multiplying several times over. Common causes include difficult Himalayan and Terai geology, weak contractor performance, slow land acquisition, fragile funding, design revisions and, in some cases, allegations of irregularities.

These delays carry a real economic cost. Every year that a command area waits for water, farmers remain dependent on erratic monsoon rains, cropping intensity stays low, and land near completed canals is sometimes converted to housing before irrigation ever arrives. Completing these schemes is therefore central to Nepal's goals of food security, rural incomes and reduced reliance on food imports.

For readers researching a specific scheme, the practical facts to check are the same for each: the river source, the barrage or headworks location, the design command area in hectares, the districts and province served, the funder, and the latest physical-progress and completion-date figures. Because progress percentages, costs and deadlines change frequently, those live figures should always be confirmed against the latest DWRI project reports or credible news coverage.