George W. Annandale, D.Ing., P.E., is an internationally known expert on scour and president of Engineering and Hydrosystems, Inc. A civil engineer with 30 years' experience, he has worked on projects involving fluvial hydraulics, sediment transport, scour and sedimentation, and hydrology and hydraulics. He is the developer of the Erodibility Index Method used to assess scour on major projects around the world, including the San Roque Dam in the Philippines, the Karahnjukar Hydroelectric Project in Iceland, and the new Woodrow Wilson Bridge in the United States. His method has also been incorp...