Irrigation is the mainstay of agriculture. Availability of irrigation facilities increases crop yields, contributes to food security and helps increase exports of agricultural products, thus resulting in a favourable trade balance. Development of agriculture contributes to the industrial sector because agriculture provides raw materials for the industry. In Nepal, agriculture contributes around one-third to the gross domestic product. It employs over 70 per cent of the total labour force. When it comes to the rural labour force, the percentage is around 80 per cent.