Interactive water quality modeling within a GIS environment

Abstract A number of water quality models have been developed to characterize the local, regional, and national extent of environmental pollution problems, and to assess the potential socio-economic impacts. These models provide an understanding of the processes involved in pollution generation from nonpoint sources and can be used to evaluate the effectiveness of alternative land management practices. However, a major problem facing modelers has been the inability to efficiently handle, manipulate, and manage large volumes of model parameters. Recent developments in geographic information systems (GIS) provide the opportunity and tools to spatially organize and effectively manage data for modeling. This paper presents an interactive water quality modeling system developed within a GIS environment. The system combines soil erosion and pollutant export models with ARC/INFO GIS software and a graphic user interface. In addition, the system is designed to allow efficient and cost-effective use of simplified water quality models for the analysis of nonpoint source pollution problems in watersheds. Implemented on a color-graphic engineering workstation, the interactive modeling system permits visualization of the spatial distribution of model inputs and of the spatio-temporal variation of simulated model outputs. The goal of developing the interactive modeling system, in general, was to provide a spatial decision support tool for targeting critical areas of water quality problems in a watershed and for agricultural production planning and management decision-making.