Nonpoint nguồn ô nhiễm là nguồn hàng đầu của suy giảm của Mỹ nước (Cơ quan Bảo vệ Môi trường Hoa Kỳ [EPA] 2002). Trong lưu vực Great Lakes, các lớp trầm tích bị ô nhiễm, dòng chảy đô thị và tràn cống thoát nước kết hợp (CSO), và nông nghiệp đã được xác định là nguồn chính của suy yếu của vùng nước bờ biển Đại Hồ (US EPA 2002). Các vấn đề gây ra bởi những chất gây ô nhiễm độc hại và ô nhiễm tác nhân gây bệnh thủy sản và động vật hoang dã, khuyến cáo. | Part III Water Quality and Biogeochemical Processes 2008 by Taylor Francis Group LLC 10 Estimating Nonpoint Source Pollution Loadings in the Great Lakes Watersheds Chansheng He and Thomas E. Croley II INTRODUCTION Nonpoint source pollution is the leading source of impairment of . waters . Environmental Protection Agency EPA 2002 . In the Great Lakes basin contaminated sediments urban runoff and combined sewer overflows CSOs and agriculture have been identified as the primary sources of impairments of the Great Lakes shoreline waters . EPA 2002 . The problems caused by these pollutants include toxic and pathogen contamination of fisheries and wildlife fish consumption advisories drinking water closures and recreational restrictions . EPA 2002 . Management of these problems and rehabilitation of the impaired waters to fishable and swimmable states require identifying impaired waters that are unable to support fisheries and recreational activities and tracking sources of both point and nonpoint source material transport through a watershed by hydrological processes. Such sources include sediments animal and human wastes agricultural chemicals nutrients and industrial discharges and so forth. While a number of simulation models have been developed to aid in the understanding and management of surface runoff sediment nutrient leaching and pollutant transport processes such as ANSWERS Areal Nonpoint Source Watershed Environment Simulation Beasley and Huggins 1980 CREAMS Chemicals Runoff and Erosion from Agricultural Management Systems Knisel 1980 GLEAMS Groundwater Loading Effects of Agricultural Management Systems Leonard et al. 1987 AGNPS Agricultural Nonpoint Source Pollution Model Young et al. 1989 EPIC Erosion Productivity Impact Calculator Sharpley and Williams 1990 and SWAT Soil and Water Assessment Tool Arnold et al. 1998 to name a few these models are either empirically based or spatially lumped or do not consider nonpoint sources from animal .
