This monograph sets forth a unified approach and principles for modeling
hydrologic processes distributed in space and time using geographic
information systems (GIS). The focus of this Second Edition is on the
principles of how to implement a distributed model using geospatial data
to simulate hydrologic processes. Once embarked on fully distributed
representations of hydrologic processes, conservation laws form the
basis for modeling, and spatial data management becomes necessary. A
physics-based approach involves the laws that govern the complexities of
all the paths that water travels, from precipitation falling over a
river basin to the flow in the river. Examples are provided that
illustrate how to represent a watershed with spatially distributed data
along with the many pitfalls inherent in such an undertaking. Since the
First Edition, software development and applications have created a
richer set of examples, and a deeper understanding of how to perform
distributed hydrologic analysis and prediction.