Abstract:
Floods are one of the most frequent and destructive natural hazards in river
basins, causing serious consequences for the community and regional development. The
intensity of seasonal monsoon rainfall and the dynamics of land use practices have
accelerated the flood events in the Deduru Oya basin. The intensity and frequency of flood
occurrences expand the exposure and vulnerability of the community. Therefore, this
study aims to assess the flood risk zonation in Deduru Oya basin and propose Flood Risk
Reduction (FRR) strategies by integrating the holistic approach. This study used the Multi Criteria Decision Analysis (MCDA) approach with Analytical Hierarchical Process (AHP)
combination of physical and socioeconomical parameters. Structured questionnaire
survey conducted to identify the FRR strategies from the communities in the high risk zone
in Deduru Oya basin. AHP technique, descriptive statistics and thematic analysis methods
were used as data analysis techniques. Flood risk map indicated that 290 km2 is very high
risk,1226.56 km2 high risk, 820.40 km2 moderate risk, 255.51 km2 low risk and 83.30 km2
risk free, respectively. The thematic analysis proposes to manage the reservations of the
river, develop proper land use practices, identify and map out the flood inundation areas,
enhancing technology for real-time flood monitoring and early alerts, develop community
preparedness, and upgrade the drainage systems and flood defences can reduce
vulnerability. In addition, legal power should be vested in local governments with legal
frameworks that define responsibilities and protocols for flood risk management, and the
weaknesses of the current legislation should be removed
