Publication Date



geographic Information System, quasi-distributed mathematical modeling, RZWQM, spatial variability, field management, water quality modeling, model integration


The Root Zone Water Quality Model (RZWQM) is a one-dimensional, lumped field-scale model. It can simulate major physical, chemical, and biological processes in an agricultural crop production system. While its reliability has been verified by several researchers, because of its lumped structure RZWQM could not account for the soil heterogeneity and the associated nonuniformity of management practices across the field. Neglecting the variability may result in misleading simulation results. On the other hand, the variability can be accurately characterized by using a geographic information system (GIS), especially ArcView GIS, the most widely used desktop mapping and geographic analysis system. Linked with ArcView GIS, RZWQM will have a quasi-distributed structure, which makes it possible to incorporate the field variability into the simulation. The linkage is realized by a series of interfaces and dialogue boxes developed in Avenue and Microsoft Visual Basic computer programming languages. The user can develop and execute such a coupled model by employing an easily-used main interface, the interfaces for preparing the input data files and displaying the simulation results, and the associated dialogue boxes. Undoubtedly, the linkage will facilitate and enhance the use of RZWQM.