This book provides essential information on the higher mathematical level of approximation over the gradually varied flow theory, also referred to as the Boussinesq-type theory. In this context, it presents higher order flow equations, together with their applications in a broad range of pertinent engineering and environmental problems, including open channel, groundwater, and granular material flows.

Oscar Castro-Orgaz is a Professor of Hydraulic Engineering at the University of Córdoba, Spain. He has written more than 50 papers in peer-reviewed journals of hydraulics and fluid mechanics and serves
as reviewer for the main journals on these topics. He is also Associate Editor of the Journal of Hydraulic Engineering ASCE, and Editorial Board Member of Environmental Fluid Mechanics,
Springer.
Willi H. Hager is Professor of Hydraulics at the Swiss Federal Institute of Technology, ETHZ. He has written more than 500 papers, of which more than half in peer-reviewed journal, mainly on open channel flows, pipe flows, scour, erosion, impulse waves, wastewater hydraulics and supercritical flows. He also wrote more than 20 books in these topics. He served from 2006 to 2011 as Editor of the Journal of Hydraulic Research, and was the recipient of various international awards.