AdvertisementLevees Make Mississippi River Floods Worse, But We Keep Building ThemMay 21, 2018Rebecca HersherfacebookEmailMike Stone, left, and Andy Sherman in the pumping station for Hannibal, Mo., during a flood in 1993. The city is protected by a flood wall, and flood managers have built up levees to protect against flooding. But scientists warn those structures are making flooding worse. (AP)