The Pesticide Root Zone Model (PRZM) simulates the vertical movement of pesticides in the unsaturated soil, within and below the plant root zone, and extending to the water table using generally available input data that are reasonable in spatial and temporal requirements. The model consists of hydrology and chemical transport components that simulate runoff, erosion, plant uptake, leaching, decay, foliar washoff, and volatilization (implicitly) of a pesticide. Predictions can be made for daily, monthly, or annual output. It is designed to run on a DEC PDP 1170 mini-computer using batch jobstream submission. With modifications, however, the model will operate on other computers with FORTRAN compilers. PRZM has a separate interactive processing software module (ANPRZM) to develop and update parameter files for calibration, verification, and production run analyses. The model has undergone limited performance testing in New York and Wisconsin (potatoes), Florida (citrus), and Georgia (corn). The results of these tests demonstrate that PRZM is a useful tool for evaluating groundwater threats from pesticide use. The manual provides information and detailed guidance on parameter estimation and model operation as well as an example application to assist model users.

"December 1984." Includes bibliographical references (leaves 125-129). "EPA-600/3-84-109."