Estimation of Runoff and Infiltration at Project Level

Colombo is highly vulnerable to flooding, and has experienced regular floods for the past 30 years, affecting over 1.2 million people annually. The recurrent floods in the Colombo Metropolitan Region (CMR) are due to a combination of factors including unauthorized constructions that increase surface runoff by reducing infiltration, dumping waste in the drainage canals, backwater build-up in the main canal system, lack of regular maintenance of the drainage system, and commercial development in wetland reservations.

In this study, an investigation has been carried out to identify and assess the effects of Urban and Peri-urban Agriculture and Forestry (UPAF) to enhance storm water infiltration and reduce the surface runoff of storm water to control the flood risk at Kesbewa Urban Council (KUC).