Hydrologic Modeling With GIS: An Overview

The integration of geographic information systems (GIS) with distributed parameter hydrologic models is playing an increasing role in designing, calibrating, modifying, and comparing these models. Successful application of GIS technology in hydrologic modeling requires careful planning and extensive data manipulation. Three major tasks identified in most hydrologic applications with sophisticated computerized numerical models are: the spatial database construction, the integration of spatial model layers, and the GIS and model interface. The first task is often time consuming, but is becoming more justifiable with the ever increasing volume of data available from many organizations. The second task can be generalized in a series of spatial overlaying and/or projecting procedures that yield the final modeling layer. This task is becoming less tedious with rapid advancement of sophisticated GIS capabilities. The last task may require actual programming with difficulty varying from case to case. This article is both an introductory overview to GIS applications in hydrologic modeling, and a review of what has been achieved in this rapidly growing field.