One of the major outfall of the Colombo Canal System is St Sebastian North Canal Outlet discharging water to Kelani River near Nagalagam Street. The width of opening at North Lock Gate is about 5m, whereas the upstream and downstream canals are 17-20 m wide and therefore existing Lock gate acts as a bottle neck for water flow during floods. These gates are closed during high floods in Kelani River in order to prevent river water entering to Colombo canal system. Since the opening at existing North Lock Gate is not adequate, it is proposed to widen this opening and to construct a new gate structure with two vertical gates with a combined width of 15m. Being a river outfall, North lock cannot function at high Kelani scenarios, and hence a pumping station with a capacity of 30m3/s will be installed adjoining the new gate structure in order to pump flood water from Colombo Canal system to Kelani River. This construction is carried out with the consent of the Department of Irrigation who is the responsible establishment for the river flooding.
