<span style="font-family:""><span style="font-family:Verdana;">Flood is a natural process generated by the interaction of various driving fac</span><span style="font-...<span style="font-family:""><span style="font-family:Verdana;">Flood is a natural process generated by the interaction of various driving fac</span><span style="font-family:Verdana;">tors. Flood peak flows, flood frequency at different return periods, and potential driving forces are analyzed in this study. The peak flow of six gauging stations, with a catchment area ranging from 169 -</span></span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">124,108 km</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> and sufficient observed streamflow data, was selected to develop threshold (3</span><sup><span style="font-family:Verdana;">rd</span></sup><span style="font-family:Verdana;"> quartile) magnitude and frequency (POTF) that occurred over ten years of records. Sixteen Potential climatic, watershed and human driving factors of floods in the study area were identified and analyzed with GIS, Pearson’s correlation, and Principal Correlation Analysis (PCA) to select the most influential factors. Eight of them (MAR, DA, BE, VS, sand, forest AGR, PD) are identified as the most significant variables in the flood formation of the basin. Moreover, mean annual rainfall (MAR), drainage area (DA), and lack of forest cover are explored as the principal driving factors for flood peak discharge in Wabi-Shebele River Basin. Fi</span></span><span style="font-family:""><span style="font-family:Verdana;">nally, the study resulted in regression equations that helped plan and design different infrastructure works in the basin as ungauged catchment empirical</span><span><span style="font-family:Verdana;"> equations to compute Q</span><sub><span style="font-family:Verdana;">MPF</span></sub><span style="font-family:Verdana;">, Q</span><sub><span style="font-family:Verdana;">5</span></sub><span style="font-family:Verdana;">, Q</span><sub><span style="font-family:Verdana;">10</span></sub><span style="font-family:Verdana;">, Q</span><sub><span st展开更多
Flood events vary with sub-regions, sites and time and show complex characteristics. This study investigated temporal variabilities in flood discharges and relationships with principal driving factors in data scarce W...Flood events vary with sub-regions, sites and time and show complex characteristics. This study investigated temporal variabilities in flood discharges and relationships with principal driving factors in data scarce Wabi Shebele River Basin. The preliminary analysis using exploratory data analysis (EDA) on annual and seasonal maximum discharge reveals that there are cycles of extreme flows at five- and ten-year intervals respectively throughout the basin. The statistical verification using the Mann-Kendall test and Quantile perturbation method indicates a significant trend in flood magnitude and frequency entire the basin in the early 21st century. For longest period (1980-2010) annual maximum stream flow shows significant positive trend (p-value < 0.05) in middle catchments and negative trend (p-value < 0.05) in eastern catchments. The years: 1986-1995, 2006-2010 are the years in which positive significant anomalies occurred in all seasons, while the years: 1980-1985, 1996-2005 are the occurrence years of significant negative anomalies. Rainfall from climate drivers;DA, BE, VS and fraction of sand from environmental background drivers;fraction of forest and population density from external factors were identified as the powerful driving factors of flood variabilities in the Wabi Shebele River Basin.展开更多
文摘<span style="font-family:""><span style="font-family:Verdana;">Flood is a natural process generated by the interaction of various driving fac</span><span style="font-family:Verdana;">tors. Flood peak flows, flood frequency at different return periods, and potential driving forces are analyzed in this study. The peak flow of six gauging stations, with a catchment area ranging from 169 -</span></span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">124,108 km</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> and sufficient observed streamflow data, was selected to develop threshold (3</span><sup><span style="font-family:Verdana;">rd</span></sup><span style="font-family:Verdana;"> quartile) magnitude and frequency (POTF) that occurred over ten years of records. Sixteen Potential climatic, watershed and human driving factors of floods in the study area were identified and analyzed with GIS, Pearson’s correlation, and Principal Correlation Analysis (PCA) to select the most influential factors. Eight of them (MAR, DA, BE, VS, sand, forest AGR, PD) are identified as the most significant variables in the flood formation of the basin. Moreover, mean annual rainfall (MAR), drainage area (DA), and lack of forest cover are explored as the principal driving factors for flood peak discharge in Wabi-Shebele River Basin. Fi</span></span><span style="font-family:""><span style="font-family:Verdana;">nally, the study resulted in regression equations that helped plan and design different infrastructure works in the basin as ungauged catchment empirical</span><span><span style="font-family:Verdana;"> equations to compute Q</span><sub><span style="font-family:Verdana;">MPF</span></sub><span style="font-family:Verdana;">, Q</span><sub><span style="font-family:Verdana;">5</span></sub><span style="font-family:Verdana;">, Q</span><sub><span style="font-family:Verdana;">10</span></sub><span style="font-family:Verdana;">, Q</span><sub><span st
文摘Flood events vary with sub-regions, sites and time and show complex characteristics. This study investigated temporal variabilities in flood discharges and relationships with principal driving factors in data scarce Wabi Shebele River Basin. The preliminary analysis using exploratory data analysis (EDA) on annual and seasonal maximum discharge reveals that there are cycles of extreme flows at five- and ten-year intervals respectively throughout the basin. The statistical verification using the Mann-Kendall test and Quantile perturbation method indicates a significant trend in flood magnitude and frequency entire the basin in the early 21st century. For longest period (1980-2010) annual maximum stream flow shows significant positive trend (p-value < 0.05) in middle catchments and negative trend (p-value < 0.05) in eastern catchments. The years: 1986-1995, 2006-2010 are the years in which positive significant anomalies occurred in all seasons, while the years: 1980-1985, 1996-2005 are the occurrence years of significant negative anomalies. Rainfall from climate drivers;DA, BE, VS and fraction of sand from environmental background drivers;fraction of forest and population density from external factors were identified as the powerful driving factors of flood variabilities in the Wabi Shebele River Basin.
