美农业研究局利用他们研制的AGNPS计算机模型来监测水上污染。该模型可把需要监测水流区域划分为任何尺寸的坐标方格，对于每个方格，输入该区的土壤类型、地貌及土壤使用状况。如作物播种后，再输入化肥农药的使用、耕作方式以及保护措施的应用情况，同时输入该地区的气象资料 The United States Agricultural Research Service uses the AGNPS computer model they developed to monitor water pollution. The model divides the area of ​​the water to be monitored into coordinate grids of any size. For each grid, enter the type of soil, topography and soil use in the area. For example, after sowing the crop, enter the application of chemical fertilizers and pesticides, the mode of cultivation and the application of protection measures, and enter the meteorological data of the area