Canal irrigation techniques have existed in Sri Lanka since ancient times, and to this day, remain a popular method of irrigation in the country.
“This system involves harnessing and storing rainwater in large reservoirs. How it works now is that whatever the amount that gets collected in a reservoir every monsoon, then gets divided up and distributed to farmers in the region,” said Mohamed Aheeyar, a researcher at the International Water Management Institute (IWMI).
Under this system, farmers have to ration out the supply they are given. They do not have their own supply and are completely dependent on what is allocated to them.
Population pressure and increasing water competition in a changing climate require us to take stock of the availability and use of water across scales. Water availability not only influences farmers’ commercial prospects but also irrigation-related enterprises and agri-businesses. Greater water scarcity could jeopardize irrigation and agricultural markets while excessive water use can lead to declining ecosystems, water quality and soil health. IWMI advises development partners and the public and private sectors on all aspects of water resource availability and use through a variety of advanced modeling and remote-sensing products and tools, including 
The ability of farmers to engage in or expand irrigation depends on the prevailing socioeconomic, ecological and political contexts, which are often complex, non-linear and changeable. Overcoming systemic barriers to farmer-led irrigation development while taking advantage of existing opportunities 
A lack of affordable credit, particularly for women and resource-poor farmers, is one of the main barriers to expanding farmer-led irrigation in low- and middle-income countries. But 
Scaling farmer-led irrigation requires strengthening human capacity and knowledge exchange among all actors and stakeholders involved. IWMI takes an action research approach, working with national and international research institutions, governments, extension agents and public and private organizations to co-develop the scaling ecosystem and strengthen capacity to drive scaling networks and collective action. We support the