Revisiting Turcotte’s approach: flood frequency analysis

Abstract Flood frequency estimation forms the basis for engineering design of hydraulic structures, including bridges and culverts, local regional development planning, flood insurance. In United States, Water Resources Council recommends using Log-Pearson Type III (LP3) distribution as a standard use with annual peak flow data. However, researchers have argued more than one streamflow value in year thus increasing sample size decreasing sampling error estimates quantiles. this study, conducted over Iowa, authors revisit method proposed by Donald Turcotte others to power-law applied values events separated time window. contrast those earlier studies, formal statistical approach based on maximum likelihood Kolmogorov-Smirnov statistic parameter estimation. They also propose novel simulation framework uncertainty distribution. apply methodology data from 62 USGS stream gauges Iowa. The key finding study is that low-probability quantile Turcotte’s result conservative when compared LP3 confirming outcomes.