Basic water measurement instruments enhance irrigation management in Nepal

Share this to :

By Nilhari Neupane, Santosh Nepal, Dinesh Bhatt, and Jonathan Lautze

The International Water Management Institute (IWMI) is introducing basic water measurement instruments to an irrigation project in Western Nepal to improve agricultural productivity. This instrumentation, introduced in collaboration with the Department of Water Resources and Irrigation (DWRI), provides real-time data on water availability and usage, assisting irrigation managers in irrigation scheduling, to allocate water according to crop type and stage of plant growth. More efficient distribution will help resolve conflicts over water allocation and benefit farmers, irrigation managers, and Water User Associations (WUAs).

Agriculture plays a key role in Nepal’s food and nutritional security and national economy, contributing about a quarter of GDP and employing more than 60 percent of the economically active population. However, Nepal’s agricultural productivity currently lags behind neighboring countries, and around 7.8 percent of the population faces moderate to severe food insecurity.

Barriers to effective irrigation management

Under the CGIAR Initiative on NEXUS Gains, IWMI and the DWRI are working to identify irrigation management challenges in three irrigation schemes in Western Nepal.

A key obstacle is the absence of canal-level flow data, which hinders irrigation managers from achieving an efficient and equitable distribution of water among farmers. At the project scale, there is high seasonal variability in the total irrigated area, primarily due to inadequate water supply in winter and spring. There is also pronounced head–tail disparity in many irrigation systems due to poor water management and inadequate water regulating structures, with farmers located at the tail-end of the canal often facing unreliable access, particularly during the dry season. Another challenge identified by the researchers is the need for effective decision making at both farm and canal levels.

Introduction of simple instruments in the Babai Irrigation Project

One focus area of the NEXUS Gains study is the Babai Irrigation Project (BIP), which has a command area of 36,000 hectares, in which rice, wheat, and maize are the dominant crops. The study found that farmers typically obtain rice yields of 3 tons per hectare, which is slightly lower than the national average. The potential yield is 4.5 tons per hectare, which is being achieved in neighboring countries.

Currently, the project’s canal gates are operated manually and irrigation managers lack comprehensive data on water allocation and distribution across the fields. In response, IWMI and DWRI, through NEXUS Gains, have begun monitoring the irrigation flow in the project’s eastern canal. This supports irrigation scheduling and the timely distribution of water for crop type and growth stage, as if farmers know how wet their soils are and how much water is flowing in the channels, they are able to use water more efficiently. Tailenders will then benefit because upstream irrigators do not overwater their crops and more water remains in the channels. The project has installed 23 manual gauges in each branch canal and one automatic flow sensor in the main canal. In addition, six soil moisture sensors will be installed. The resulting data will be available to irrigation managers and farmers via an online dashboard.

On a recent field visit, researchers from NEXUS Gains observed that farmers at the tail-end of BIP experienced significant difficulties in accessing water to cultivate crops in spring and winter, while farmers situated near the primary and subsidiary canals received an adequate and more consistent supply. Furthermore, owing to discharge variability in the Babai River, flow in the main canal oscillates from a maximum of 57 cubic meters per second during the monsoon, to 5 cubic meters per second in the dry season, posing a substantial challenge in ensuring a stable water supply for irrigation. Climate change is anticipated to intensify this flow variation in future.

The integration of simple and cost-effective tools for water measurement could reduce the yield gap in BIP; even a modest change could result in the addition of thousands of tons of cereal. The cost of installing these instruments is small in comparison to the potential benefits, as demonstrated in Pakistan’s extensive Indus Basin irrigation network, where most canals have flow meters installed.

Mr Pratik Kandel, an engineer working on BIP’s eastern canal, has a positive outlook regarding the impact of new technology on improving efficiency and reducing the workload at the irrigation office. While acknowledging potential challenges related to the security of sensors and real-time data collection during the initial one to two months, he highlighted the importance of training gauge readers and WUA members to use the new instruments.

Likewise, Mr Bali Ram Chaudhary, the head of the WUA for the eastern canal, is optimistic about the potential of tools like flow meters and soil moisture meters to enhance the water allocation in the area. Despite his limited familiarity with these instruments, the ongoing pilot projects conducted by IWMI and DWRI are expected to help him and other WUA members understand the functionality of these tools, and how the data they generate can contribute to informed decision making.

Furthermore, with many men farmers leaving Nepal in search of employment, women are increasingly taking up the management of irrigation. Providing them with instruments that facilitate data-based decision making, supports them to make informed choices about irrigation scheduling (such as water use) and crop selection. Historically, women have been the main contributors to agriculture, but in more recent years, the power dynamics have consistently favored men farmers and their kinship in WUAs. Challenges persist in making WUAs more inclusive and improving the participation of women in decision making and benefit sharing. Installing simple instruments will not bring a substantial change to these persistent issues but it could be a small first step toward improving them.

Data gathering for efficient irrigation and empowerment

Nepal’s agricultural sector requires data-driven innovations for more efficient and equitable irrigation decision making. The deployment of simple, low-cost instruments can improve crop yields, minimize inequalities in the benefits derived from irrigation, reduce irrigation-related conflicts, conserve resources, and empower women and youth to make informed decisions regarding irrigation and crop selection. These small interventions can lead to substantial socio-economic benefits while aligning with government policies and addressing key challenges in the sector. Wider adoption of these interventions could contribute to achieving Nepal’s Sustainable Development Goal 2 targets. Instrumentation is a smart and affordable way to elevate the state of irrigated agriculture in Nepal and contribute to the country’s growth.

Nilhari Neupane is a National Researcher at IWMI Nepal; Santosh Nepal is a Researcher at IWMI Nepal; Dinesh Bhatt is Superintending Engineer at DWRI Nepal; and Jonathan Lautze is Research Group Leader – Integrated Management of Basins and Aquifers, IWMI South Africa.

This work was carried out under the CGIAR Initiative on NEXUS Gains, which is grateful for the support of CGIAR Trust Fund contributors:


Header image: Guage installation in a canal of the Babai Irrigation Project. Photo by Ammar Bahadur Kunwar.

Share this to :