It flows through or borders the Sri Lankan districts of Nuwara Eliya, Ratnapura, Kegalle, Gampaha and Colombo.

These two contribute to hydro-electric production in Sri Lanka, housing several major reservoirs, ponds and power stations.

In addition, Kelani River water levels affect the flood risk to Colombo, the capital of Sri Lanka, to a considerable extent.

Regulation, in order to prevent saline intrusion, can reduce the water quality in other ways, and can increase the flood risk.

The Kelani stream flow was investigated just upstream of Ambatale at Hanwella, with engineers analyzing the river discharges from 1973 to 2004 (in million m3/month).