Flood occurrence in relation to land use change and La-Niña events in Kota Marudu District, Sabah

Siti Nurhidayu Abu Bakar, Nancy Adoh

Tuesday 30 june 2015

16:00 - 16:15h at South America (level 0)

Themes: (T) Flood risk management and adaptation, (ST) Flood risk assessment

Parallel session: 7J. Floodrisk - Assessment

Poor land use management especially on hilly areas, inadequate drainage system coincide with La-Niña phenomenon frequently leads to flood events, and it has severe impacts on environment and socio-economy for the affected areas. This study analysed flood probability in Kota Marudu, Sabah based on rainfall and water level data in Kota Marudu between 2000 and 2012 in relation to land use change and Southern Oscillation Index (SOI). Small variability (p<0.005) from all stations with the higher average annual rainfall (AAR) for Ongkilan is the highest which demonstrates similar pattern during the study period. Flood occurrence was recorded twice per year in 2000, 2006 and 2009. While the longest day of flood recorded on 1st to 15th Jan 2007 (16 days). Significant relationship was observed between SOI with flood occurrence in Kota Marudu from 2000 to 2010 (p<0.0001). Flood mitigation action taken by the authorities efficiently prevent the flood occurrence in the strong La-Niña year in 2008 (AAR>3000mm of all stations). However, there is strong influence of land use, due to urbanization and development, and topography features where more frequent flood events were recorded in Tandek compared to Kota Marudu (p<0.0001). The flood probability could be projected in the flood prone area such as Kota Marudu for more efficient mitigation plan and controlling action.