The practice of linking Geographic Information Systems (GIS) software and natural resource models has greatly increased in the recent past. Cheaper and more powerful computing resources have allowed us to build systems that minimize the effort and labor involved in parameterizing simulation models. However, by using computerized means to minimize the effort needed to facilitate model parameterization we have increased the complexity in these links between the two components. We have also increased the amount of knowledge required to build the link and have increased the need to understand the consequences of building the links between two systems. The practice of linking these two components creates new issues that affect both the GIS analyst and the researcher. The goal of this research project has been to develop an application linking GIS-based geo-processing tools developed in the Automated Geospatial Watershed Assessment (AGWA) tool to an internet-based map interface. The application allows a user to develop a management scenario by delineating a watershed based on one or more outlet points. The application uses the delineation and other input data sets to develop input parameter files for a hydrologic model, which then runs and produces output for the user. The development of the application produced many interesting issues, but the one identified as most important in terms of this dissertation research was an issue related to using current software development tools such as the Universal Modeling Language (UML) and software design patterns as a way to communicate about system requirements and system functions between programmers and project stakeholders. This research will examine how these software development tools were used to develop DotAGWA, the consequences of using the tools and an analysis of why these tools may be an important component in developing natural resourceprojects that rely heavily on GIS tools.