The
Kelani River (
Sinhala Kelani Ganga) is a 145&_160;km (90&_160;mi) 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 covers approximately 80% of the water supply to Colombo. In addition to that, the river is used for
transportation,
fisheries,
sewage disposal,
sand mining and for production of
hydroelectricity. Due to these, many people depend on the river for their daily routine in life. Depending on the operation of three
reservoirs, the river flow varies from 20&_160;m
3 (706&_160;cu&_160;ft) to 25&_160;m
3 (883&_160;cu&_160;ft) in the dry seasons, and 800&_160;m
3 (28,252&_160;cu&_160;ft) to 1,500&_160;m
3 (52,972&_160;cu&_160;ft) during the
Monsoon season. The annual sand extraction from the river is approximately 600,000&_160;m
2 (6,458,346&_160;sq&_160;ft) to 800,000&_160;m
2 (8,611,128&_160;sq&_160;ft) per year. From a
barge, people dive to the river bed, from where the sand is lifted to the barge in a bucket, and when the barge is full, it is taken to the
river bank unloaded by a separate team. The sand mining causes the river bed to sink by approximately 10&_160;cm (4&_160;in) per year. At present, two main concerns in connection with the river are
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 for both nationally and to the many involved people.
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