Flood Predictions Incorporating Historic Information Through the 3 Parameters Log-Normal Distribution

Abstract

The importance of historic flood information is pointed out, as a complement to systematic records; oriented to guarantee the fit of probabilistic flood estimates to community experience and to improve statistically such predictions. The simplest method that incorporates historic information in flood studies is exposed in detail, named historically weighted moments, the equations to fi t the three parameters in log-normal distribution are also listed. Then, a simple plotting positions formula is exposed, in order to show in probability paper this combined data (historic and systematic). Late, four numerical applications in rivers with historical and recent flood information are described, the information has previously been reported in technical papers. Finally, one conclusion is formulated relative to the process described and the numerical results obtained.