Role of Environmental Factors in Managing Flood Risk Perception of Vulnerable Communities: A Study of Kelani River Basin, Colombo, Sri Lanka

Abstract

Floods are one of the catastrophic disasters causing human and property loss while hindering the economic growth of cities. Colombo city, the commercial capital of Sri Lanka, is located in a coastal low-lying area within the Kelani River Basin, the third largest river in Sri Lanka. Residents in Colombo and suburbs around the Kelani River faced significant losses due to floods and extreme weather events in the recent past. By considering the frequent effects of floods, this study evaluates the association of socio-demographic and physical environmental factors on flood risk among vulnerable communities living in Colombo city and suburbs. A questionnaire survey of 100 flood-affected communities was conducted with a photographic review of adaptation and mitigation measures among the residents living along high flood-risk regions. Flood risk factors were analyzed using Ordinal Logistic Regression (OLR) for eight variables selected from covariant analysis. OLR results revealed that employment type, property ownership, waste management, and safe sanitation are significantly associated with flood risk among vulnerable communities. At the same time, physical mitigation measures allowed people to cope during a flood event. Moreover, observations revealed that community cooperation and local-level mitigation strategies are comparatively high among most affected communities within the flood risk zone. The results show socio-demographic and infrastructure factors influencing flood damage and risk, often overlooked beyond floodwater removal in Colombo. Urban planning and disaster management agencies should prioritize community perception and socio-demographic factors to improve recovery through optimal resource allocation during flood disasters.

Keywords: Flood Risk, Physical and Social Factors, Community Recovery