Effect of observation errors on the uncertainty of design floods

This study investigates the uncertainty in the estimation of the design flood induced by errors in flood data. We initially describe and critically discuss the main sources of uncertainty affecting river discharge data, when they are derived using stage-discharge rating curves. Then, different error structures, recently proposed by the literature, are used to investigate the effects of flood data errors on design flood estimation. Annual maxima values of river discharge observed on the River Po (Italy) at Pontelagoscuro are used as application example. The study demonstrates that observation errors may have a significant impact on the uncertainty of design flood, especially when rating curve is affected by systematic errors.