Integration of geographic information systems with simulation models for watershed erosion prediction

Abstract

Watershed management concerns are focused on conserving land and water resources. To address such concerns, there is a need for an in-depth understanding of the complex and inherent variability of natural processes occurring in watersheds. Soil erosion models were developed as tools to enhance watershed resource management. Geographic information systems (GIS) offers new perspectives in attaining a better understanding of soil erosion processes. The superior capability of GIS in handling spatial data contributes to its growing applications in soil erosion modeling. The framework developed in this study allows the integration of existing computing tools to enhance soil erosion simulation. The components of the framework includes: the ARC/INFO geographic information systems, the ORACLE relational database management system, the Revised Universal Soil Loss Equation (RUSLE) and Modified Universal Soil Loss Equation (MUSLE), and a graphical user interface (GUI). The use of GIS technology allows integration of diverse spatial data into a comprehensive spatial database. Characterization of a watershed as to soils, land use and other features is done in a shorter period of time than if it were done manually. The relational database is a convenient tool to store tabular data. This organized archive of data allows easy retrieval and update of inputs to simulation models. The study shows that subdividing a watershed into a set of hydrologic response units (HRUs) provides an improved ability to integrate spatial variability into soil erosion prediction models. The incorporation of a graphical user interface as the user-system link automates execution of the different ARC Macro Language (AML) programs and enables users to operate the system without in-depth understanding of its individual components.