CORRELATION BETWEEN EXTREME RAINFALL AND INSURANCE CLAIMS DUE TO URBAN FLOODING - CASE STUDY FREDRIKSTAD, NORWAY

During the last decades an increase in extreme rainfall has led to more urban flooding. This study is based on insurance claims of damages caused by heavy rain during 2006-2012 in Fredrikstad, Norway. Data are analysed using Principal Component Analysis. The purpose has been to find characteristics of extreme rainfall and its influence on the extent of urban flooding. The number of claims seems to be peaked in the late summer period. Furthermore, the precipitation depth the week before an extreme rainfall seems to have significantly influence for the pay out from insurers, and thus the changing in runoff factor due to soil wetness is of importance. Compared to 25-year frequency rainfall with 30 min duration, relatively less intensive, but more stable and long-lasting rain seems to lead to more claims. Experiences from previous events may help to determine the level of flood risk when extreme rainfall is forecasted.

[1]  Aleksandra Kazmierczak,et al.  Surface water flooding risk to urban communities: Analysis of vulnerability, hazard and exposure , 2011 .

[2]  M. Holy,et al.  Erosion and environment. , 1980 .

[3]  Peijun Shi,et al.  The effect of land use/cover change on surface runoff in Shenzhen region, China , 2007 .

[4]  Lawrence E. Band,et al.  Simulating runoff behavior in an urbanizing watershed , 2000 .

[5]  D. McEvoy,et al.  Adaptation Strategies for Climate Change in the Urban Environment: Assessing Climate Change Related Risk in UK Urban Areas , 2004 .

[6]  A. Semadeni-Davies,et al.  The impacts of climate change and urbanisation on drainage in Helsingborg, Sweden: Combined sewer system , 2008 .

[7]  Adrian J. Saul,et al.  Sewer system operation into the 21st century, study of selected responses from a UK perspective , 2008 .

[8]  A. Bronstert,et al.  Land-use impacts on storm-runoff generation: scenarios of land-use change and simulation of hydrological response in a meso-scale catchment in SW-Germany , 2002 .

[9]  H Alegre,et al.  Prioritization of rehabilitation interventions for urban water assets using multiple criteria decision-aid methods. , 2012, Water science and technology : a journal of the International Association on Water Pollution Research.

[10]  A. Pathirana,et al.  Impacts of Climate Change on Rainfall Extremes and Urban Drainage Systems , 2012 .

[11]  A. Semadeni-Davies,et al.  The impacts of climate change and urbanisation on drainage in Helsingborg, Sweden: Suburban stormwater , 2008 .

[12]  Murugesu Sivapalan,et al.  Transformation of point rainfall to areal rainfall: Intensity-duration-frequency curves , 1998 .