Kelani River (කැලණි ගඟ)
The Kelani River is a 145-kilometre-long (90 mi) river in Sri Lanka. Ranking as the fourth-longest river in the country, it stretches from the Sri Pada Mountain Range to Colombo. It flows through or borders the Sri Lankan districts of Nuwara Eliya, Ratnapura, Kegalle, Gampaha and Colombo. The Kelani River also flows through the capital of Sri Lanka, Colombo, and provides 80% of its drinking water. The Kelani River has two main tributaries in its upper reaches: the Kehelgamu Oya and the Maskeli Oya. These two contribute to hydro-electric production in Sri Lanka, housing several major reservoirs, ponds and power stations. Castlereigh Reservoir and Norton Reservoir are constructed across the Kehelgamu Oya, while Maskeliya Reservoir, Canyon Reservoir and Laxapana Reservoir are constructed across the Maskeli Oya. In its lower reaches, some more tributaries connect to the Kelani River, out of which the most famous are the We Oya at Yatiyanthota, the Gurugoda Oya at Ruwanwella, and the Seethawaka Ganga at Avissawella.
The Kelani supplies approximately 80% of the water used in Colombo. In addition, the river is used for transport, fisheries,sand mining and for production of hydroelectricity. Through these factors, many people depend on the river for their daily routine in life. At present, two main concerns in connection with the river are flooding during the monsoon and saline intrusion in the dry season. In addition, Kelani River water levels affect the flood risk to Colombo, capital of Sri Lanka, to a considerable extent. One reason is that part of the city and suburbs of Colombo lie on the lower flood plain of the river. Exposure of Colombo and the upper catchments of Kelani River to the South West Monsoon is another reason.
The problems are related: the saline intrusion is enhanced by the deepening of the river caused by the sand mining. Regulation in order to prevent the saline intrusion can reduce the water quality in other ways, and can increase the flood risk. Sand mining is economically important nationally and to the many people involved. Kelani River is connected closely with the Sinhala Buddhist culture of Sri Lanka, especially with the people living on the area identified as the Kelani Valley. This derives primarily from the fact that the Kelani River is associated with two of the most venerated Buddhist shrines and pilgrimages, i.e. Sri Pada Mountain and Kelani Raja Maha Viharaya.