• The Walawe River basin, located in the southeast, has an area of 2,500 km2 and covers 4% of the total landmass of the Sri Lanka, it is one of the nation’s biggest basins.
• Recent water resources development has linked some adjacent small river basins to the Walawe basin. Thus, the total area covered in this study is 3,300 km2 and includes the Malala Oya, Kachchigal Oya and Karagan Oya.
• The annual flow of the Walawe River is 1.5 billion m3, or 3% of the country’s total renewable water resources.
• In the Walawe basin, more than 95% of the total volume of water diverted is for irrigation.
• There are four hydroelectric power plants in the Walawe basin, with total installed capacity of about 130 MW, representing about 10% of the country’s overall installed hydropower capacity.
• District values indicate that access to safe drinking water in the Walawe basin ranges from 73% to 83%, which compares well with the national average of 85%. However, as piped water is not available around the clock in several locations and there are quality problems during dry periods, those percentages represent an optimistic upper limit.

The section “Did You Know…?” is taken from the 3rd World Water Development Report “Water in a Changing World“.