This study developed a set of techniques to assist the decision-making process in agricultural watershed management. As local governments develop water reservoirs for water storage and use, there is need to accurately forecast not only the amounts of runoff going into reservoirs, but also the patterns and potential quantities of peak flow. Major components of the study involved the accurate modeling of the hydrology of an agricultural watershed, the enhancement of the presentation of simulated hydrology results to decision-makers, and the exploration of alternative management options in an agricultural watershed. The objectives of this study were to: (1) evaluate the performance of a distributed-parameter hydrologic model to simulate daily runoff of an agricultural watershed, (2) visualize the simulation results generated by the model from observed data, and (3) use the visualization procedures developed to examine scenarios of impacts of alternative land management practices on the streamflow from an agricultural watershed. Geographic information systems (GIS) techniques were used to prepare input data for the Precipitation and Runoff Modeling System (PRMS) to simulate surface hydrology of an agricultural watershed. Results from the simulation were then used as input for a dynamic visualization process. The visualization procedures developed in this study assisted in the examination of different scenarios of streamflow resulting from alternative land management practices. New procedures were developed for the evaluation, application and visualization of results of a widely used hydrologic modeling system.