It is proposed to construct two underground tunnels, one in Mutwal area to control floods in Colombo North and other one in Torrington area in order to mitigate floods by introducing new outfalls to the sea.The new Mutwal Tunnel, which will be built to control floods in Colombo North, will begin at the mouth of the Aluth Mawatha main drain, runs underground through the New Mutwal area and discharges the water to sea at Mutwal area near the Muthuwella fishing harbor.
New Mutwal Tunnel lined with a thick concrete inner layer is 3 meters in diameter and 760 meters long. The capacity through the tunnel is 15 cubic meters (15000 liters) per second.Final plans for the construction of the New Mutwal tunnel began last year. China Petroleum Pipeline Engineering Company Limited, an experienced foreign company will construct the tunnel. Construction supervision is done by Yooshin Engineering Co Limited under the implementation by the Sri Lanka Land Development Corporation.
The families living in the Aluth Mawatha Grama Niladhari Division in New Mutwal (Nawamutuwella) have been educated on this project. A land extent of 1,719 hectares belonging to 150 families will be taken over for the project and the government has already paid Rs. 548 million as compensation to those affected by the project.Another Rs. 252 million have been spent to provide housing to 63 unauthorized families who lost their houses due to the tunnel construction.
The MCUDP with the financial assistance of the World Bank commenced in 2013 with an objective of reducing flooding in the catchment of the Colombo water basin. It is financing large and complex flood management investments across the city.A dedicated Project Management Unit has been working to design and implement flood mitigation infrastructure. This infrastructure includes a network of pumping stations, canal bank protection, and small scale and larger scale drainage tunnels - such as Mutwal.The cumulative effect of this infrastructure will help meet the MCUDP objective of reducing flooding in Colombo, Darshini De Silva, Senior Environment Specialist representing World Bank Country Director for Maldives, Nepal and Sri Lanka said.
