Bivariate Analysis of Concurrent Flooding

This study investigates the probability of concurrent flooding near and around the confluence of the Meramec ans Mississippi Rivers in Missouri. A new general approach called the “bivariate probability method” was developed as a result of this investigation.The “bivariate probability method” utilizes the fit of a bivariate probability distribution in order to describe the probability relationship between tributary river flow and main river stage. A backwater program is used for the conversion of the tributary river. The method also the implements the theory of total probability so that all flow/stage combinations which could have created a given stage on the tributary river are accounted for in the probability computations.An important aspect of the proposed methodology is the applicability to basins which have limited periods of record. This application is accomplished by using relationships developed between the short-term gage and nearby longer-term gage to estimate the parameters required to fit the bivariate probability distribution.