Deduru Oya (දැදුරු ඔය)
The Deduru Oya is the sixth-longest river of Sri Lanka. It measures approximately 142 km (88 mi) in length. It runs across four provinces and five districts.Its catchment area receives approximately 4,313 million cubic metres of rain per year, and approximately 27 percent of the water reaches the sea. It has a catchment area of 2,616 square kilometers.
Deduru Oya Dam
The Deduru Oya Dam is an embankment dam built across the Deduru River in Kurunegala District of Sri Lanka. Built in 2014, the primary purpose of the dam is to retain approximately a billion cubic metres of water for irrigation purposes, which would otherwise flow out to sea. Site studies of the dam began in 2006 and construction started in 2008. It was ceremonially completed in 2014, with the presence of the then President Mahinda Rajapaksa. The mouth of Deduru Oya, approximately 80km downstream of the dam. Site studies and design of the dam was done by engineers from the Ministry of Irrigation. The dam, which measures approximately 2,400 m (7,900 ft) wide, creates the Deduru Oya Reservoir, which has a capacity of 75,000,000 m3 (2.6×109 cu ft). Water from the reservoir is used to irrigate approximately 11,000 hectares (27,000 acres) of farmland, while also powering a 1.5 megawatt hydroelectric power station, operated by the Ministry of Power and Energy.
In addition to the eight sluice gates, water from the reservoir is channelled from the reservoir (for irrigation) via three canals, namely the Left Canal, Central Canal, and the South Canal. The South Canal is a trans-basin concrete canal measuring 33 km (21 mi), channelling water from the Deduru Oya Reservoir to the Inginimitiya Reservoir at a flow rate of 300 cu ft/s (8.5 m3/s).