ABSTRACT
Several water quality models are available for use in assessing the effects of agricultural management on the environment. Two of the models, the Erosion-Productivity Impact Calculator and the Simulator for Water Resources in Rural Basins, are presented in more detail to serve as examples of field and watershed scale water quality models. Groundwater Loading Effects of Agricultural Management Systems considers soil properties and weather characteristics in estimating management impacts, such as planting dates, cropping systems, irrigation scheduling, and tillage operations, have on pesticide movement. B. J. Barfield et al. agree that the reason for developing models is to have a tool for analyzing environmental impacts and designing water quality and hydrologic systems. Models are being used in conjunction with monitoring to help identify current water quality problem areas and to estimate the benefits of water quality improvement practices. Initially, simulated model results were compared with measured water yields, peak flow rates, and sediment yields.
