The last few years have witnessed an enormous interest in application of GIS in hydrology and water resources. This is partly evidenced by organization of sev eral national and international symposia or conferences under the sponsorship of various professional organizations. This increased interest is, in a large measure, in response to growing public sensitivity to environmental quality and management. The GIS technology has the ability to capture, store, manipulate, analyze, and visualize the diverse sets of geo-referenced data. On the other hand, hydrology is inherently spatial and distributed hydrologic models have large data requirements. The integration of hydrology and GIS is therefore quite natural. The integration involves three major components: (1) spatial data construction, (2) integration of spatial model layers, and (3) GIS and model interface. GIS can assist in design, calibration, modification and comparison of models. This integration is spreading worldwide and is expected to accelerate in the foreseeable future. Substantial op portunities exist in integration of GIS and hydrology. We believe there are enough challenges in use of GIS for conceptualizing and modeling complex hydrologic processes and for globalization of hydrology. The motivation for this book grew out of the desire to provide under one cover a range of applications of GIS tech nology in hydrology. It is hoped that the book will stimulate others to write more comprehensive texts on this subject of growing importance.

Contains 122 unannotated abstracts on simulation models, geographic information systems (GIS) and nonpoint-source water pollution in agriculture. Includes subject and author indices.

A discussion of the role of modeling in the management process, with an overview of state-of-the-art modeling applications. The first chapters provide a background on the benefits and costs of modeling and on the ecological basis of models, using historical applications as examples, while the second section describes the latest models from a wide selection of environmental disciplines. Since management frequently requires the integration of knowledge from many different areas, both single discipline and multidiscipline models are discussed in detail, and the author emphasizes the importance of understanding the issues and alternatives in choosing, applying, and evaluating models. Land and watershed managers as well as students of forestry, park management, regional planing and agriculture will find this a thorough and practical introduction to all aspects of modeling.

Published by the American Geophysical Union as part of the Geophysical Monograph Series, Volume 108. Non-point source (NPS) pollution in the vadose zone (simply defined as the layer of soil extending from the soil surface to the groundwater table) is a global environmental problem. Characteristically, NPS pollutants are widespread and occasionally ubiquitous in extent, thus making remediation efforts difficult and complex; have the potential for maintaining a relatively long active presence in the global ecosystem; and may result in long?]term, chronic health effects in humans and other life forms. Similar to other global environmental issues, the knowledge and information required to address the problem of NPS pollutants in the vadose zone cross several technological and subdisciplinary lines: spatial statistics, geographic information systems (GIS), hydrology, soil science, and remote sensing. Cooperation between disciplines and scientific societies is essential to address the problem. Evidence of such cooperation was the jointly sponsored American Geophysical Union Chapman/Soil Science Society of America (SSSA) Outreach Conference that occurred in October 1997, entitled “Applications of GIS, Remote Sensing, Geostatistics, and Solute Transport Modeling to the Assessment of Non-Point Source Pollution in the Vadose Zone.” The objective of the conference and this book, which was developed from the conference, was to explore current multidisciplinary research for assessing NPS pollution in soil and groundwater resources.

The Application of Advanced Information Technology in Assessing Environmental Impacts. Opportunities and Limitations of GIS-Based Modeling of Solute Transport at the Regional Scale. Geostatistics: Tools for Advanced Spatial Modeling in GIS. Stochastic Solute Transport Modeling Trends and Their Potential Compatibility with GIS. GIS Applications of Deterministic Solute Transport Models for Regional-Scale Assessment of Non- Point Source Pollutants in the Vadose Zone. The Influence of Transport Variability Structure on Parameter Estimation and Model Discrimination in Field Soils Uncertainty in Regional-Scale Assessments of Non-Point Source Pollutants Sensitivity Analysis for Regional-Scale Solute Transport Modeling GIS and Hydrologic Models of Non-Point Source Pollutants in Subsurface Water. Application of Soil Survey Attribute Data to GIS Pollution Assessment Models. Methods for Estimate Soil Hydraulic Parameters for Regional-Scale Applications of Mechanistic Models. Mapping the Areal Distribution of Soil Parameters with Geophysical Techniques. An Integrated Approach for Modeling Water Flow and Solute Transport in the Vadose Zone. Unsatchemgeo: Modeling Water Flow and Multicomponent Solute Transport in a GIS Context. Baseflow Mapping of the South-Central and Southeastern United States Using GIS. Application of GIS to the Modeling of Pesticide Leaching on a Regional Scale in the Netherlands. NLEAP/GIS Approach for Identifying and Mitigating Regional NO3-N Leaching. GIS Applications to the Basin-Scale Assessment of Soil Salinity and Salt Loading to Groundwater.