Preface: Special issue on the MATERHORN program and complex terrain flows

Environmental Fluid Mechanics is devoted to the publication of basic and applied studies broadly relating to natural fluid systems, particularly as agents for the transport and dispersion of environmental contamination. Understanding transport and dispersion processes in natural fluid flows, from the microscale to the planetary scale, serves as the basis for the development of models aimed at simulations, predictions, and ultimately sustainable environmental management. Within this scope, the subject areas are diverse and may originate from a variety of scientific and engineering disciplines: civil, mechanical and environmental engineering, meteorology, hydrology, hydraulics, limnology, and oceanography.