Overview
The Kelani River is a 145-kilometre-long 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.
Description
Kelani Ganga is not the largest river of Sri Lanka, but one of the most important. It covers 80 percent of the water supply to Colombo. In addition, it is used for hydropower production, transport, irrigation, fisheries, and sewage disposal, and sand is extracted from its bed. In these ways, many people depend on the river for their daily life.
The flow varies between 800-1500 m³/s during the monsoon and some 20-25 m³/s in the dry season, depending on the operation of 3 reservoirs in the catchment. There is no regulation at the mouth.
The annual sand extraction is 600-800,000 m³ per year. The sand is mined exclusively by hand. From a moored barge, people dive to the river bed, from where the sand is lifted to the barge in a bucket. When the barge is full, it is taken to the bank, and the sand is unloaded by a separate team.
The sand mining causes the river bed to sink by some 10 cm per year.