I have tried to express in this book some of the ways that biological, physical, cultural, and urban systems at the surface of the earth operate. Of the many different forms of mass and energy these systems receive and transform, this book deals primarily with water seen in association with other forms of matter, including pollutants, and with several forms of energy; in other words, with the hydrodynamics of ecosvstems.
Since it concentrates on the reception, processing, and transformation of water by ecosystems at the earth/air interface, the book is not a conventional hydrology or hydrometeorology text. It considers off-site flow, for instance, not from the viewpoint of channel hydrology, but as ecosystem yield, which is a counterpoint to input in these systems and a consequence of the modes of transformation.
The book approaches the dynamics of water in terrestrial systems through the budgets of water in each zone or environment of a system, e.g., the canopy, the ground surface, the soil, and so on. These zones extend the overall water budget in hydrology, which, expressed in numerous models and prediction procedures, long ago proved its worth, and which I met in flood engineering in 1941. Shortly thereafter I saw its association with the energy budget at the earth's surface in the generation of snow-melt floods...