Countries around the world face increasing populations, with no corresponding increase in water supply. Problems of conserving and allocating water become, as a consequence, more and more acute, more and more pressing. Fortunately, recent advancements in data collection and software technology are now helping scientists better model how water behaves. With its ability to pull spatial data from different sources into an integrated environment, GIS simplifies the process of preparing data for hydrologic and hydraulic modeling, and greatly extends the analytical power of the model. Application such as watershed delineation, topographic characteristic extraction, floodplain extent determination, and other provide an informed basis for sound decision making for water resource professionals. The papers in this book were among those presented at the 1999 ESRI International User Conference on hydrologic and hydraulic water quantity modeling support using GIS. Although the models featured were developed for specific applications, the techniques presented apply to any hydrologic or hydraulic model that requires spatial input or that produces spatial output.
