Irrigation Development
Sustainable Managable Models Essential

By Khilendra Basnyat

NEPAL, with more than eighty per cent of the people relying on farming is predominanly an agrarian country. It has been estimated that more than two-thirds of the country’s income comes from agro-products.

Although the government has been according high priority to agriculture, the achievement made in this sector is still far from satisfactory. One of the main impediments in our agricultural development is the lack of irrigation system.

Despite abundant water resources in Nepal, its large chunk of arable land in the country is yet to be irrigated and the farmers depend on monsoon rain for irrigation. Since agricultural production is directly linked with irrigation facilities, the lack of proper irrigation facilities has meant Nepal’s farm output has not augmented to the desired extent.

Only a few decades ago, Nepal used to be a food exporter country. However, it has now become a food importer country. Considering the need of irrigation for boosting agricultural production, the government has been making continuous endeavours to launch several irrigation projects in different parts of the country.

In order to provide more irrigation facilities to more farmers, the Department of Irrigation has launched some irrigation projects in various parts of the country. Likewise, the Agricultural Development Bank has launched some micro irrigation projects. Still Nepal’s large areas of cultivable land remain unirrigated. Consequently, it has not been able to jack up agricultural production.

Nepal’s water resources can irrigate over six million hectares of land. This is of special interest to our southern neighbours when one considers that Nepal’s total arable land is only about three million hectares.

Till now, medium level projects have been launched in hilly regions and the large level projects in the Terai. In some parts of the country, small irrigation projects have been found fruitful, being less expensive and easy to manage. The government has helped launch such projects through its own finance and through international organisations as well.

Due to the rugged terrain, poor economic condition and shortage of skilled manpower, our rivers have not been utilized to the fullest extent. If small irrigation projects a launched in different parts of the country, our reliance on rainwater can be reduced and more cultivable land can be created.

The irrigation sector performance is also not satisfactory. There is doubt in the quantitative achievement record because the quality of the public sector dam is very poor. According to the Economic Survey 1990/91, there has been no increase in productivity despite the increase in irrigated area. The Agricultural Sector Review (1990) also had made a similar observation.

In accordance with the Master Plan Study Second Cycle Report, only six and half per cent is the net command area. The Agricultural Sector Review (1990) has shown that only twenty-five per cent of the irrigated sector under the public managed system received water throughout the year. However, people managed small irrigation systems have been reported to be performing better than others.

It has been discovered that most of Terai can be irrigated by the groundwater as a complementary irrigation to surface or especially for conjunctive use.

Since most of the medium and small surface water sources have been diverted for supplementary irrigation to meet extra requirements during the rainy season, immediate addition in irrigation is possible only by tubewells. Most Terai districts contain shallow and deep aquifers to meet the irrigation needs, and groundwater use is sustainable. What is more, the conjunctive use of surface and groundwater can help to provide water round the year and also to lower the water table, thereby preventing water logging, salinity and alkalinity problems.

Some deep aquifers are in artesian condition and can provide irrigation without the use of energy. However in other areas shallow aquifers need energy in order to lift water. Instead of having several diesel engines, rural electrification can help develop irrigation.

Bheri, Babai and Sunkosi-Trijuga diversions have been playing a significant role to meet recharge demand as well as surface water needs for irrigation. Apart from these, Kaligandaki-Tinau, Rapti-Kapilbastu diversions may help to make even distribution of surface water in Terai.

Most of Nepal’s rivers, except those originating from the Terai and Siwalik, are perennial in nature. However, their discharge is reduced considerably in winter with the result that all irrigation schemes have not been useful all the year round. In order to make them year round, one has to build dams and use groundwater as well. In the midland area where valleys are wide and gradient is flat in certain areas, dams can be constructed for irrigation.

In fact, Nepal has technology and resources for the execution of irrigation projects especially for the diversion of small and medium rivers as well as digging of tubewells. The main problem is inadequate funds.

In the current fiscal year also the government has accorded due priority to irrigation projects in order to reduce dependency on monsoon. For this emphasis has been given to surface irrigation facilities as well as shallow and deep well schemes. This is expected to help small and marginal farmers to get benefit from irrigation projects launched by the government or otherwise. However, there are many complaints relating to delays in construction and completion of projects which have increased expenditure for them.

The recognition that irrigated farming can only be sustainable if farmers actively participate has caused an increase in projects aimed at transferring responsibility to water user groups. Novertheless, documented success stories are still rare because the approach also has its limitation. It has been proved by empirical studies that transferring responsibility to water user groups demand a high degree of mutual trust among farmers.

In fact, sustainable irrigation has become possible in relatively small irrigation projects with a population of a largely homogeneous ethnic composition. However, the challenge ahead lies in developing and testing sustainable managable models for large irrigation projects.

Other Stories

• A Question Of Balance
• Lost And Found