Chức năng phòng hộ đầu nguồn tổng quát tải (GWLF) mô hình ban đầu phát triển tại Đại học Cornell Douglas Haith và liên kết (Haith và Shoemaker 1987; Haith et al. 1992) là "một thỏa hiệp kỹ thuật giữa chủ nghĩa thực nghiệm hệ số xuất khẩu và sự phức tạp của mô hình mô phỏng hóa học " (Haith et al, 1992, ). Cách tiếp cận GWLF conceptualizes đầu nguồn như là một hệ thống của các vùng đất khác nhau - các đơn vị phản ứng thủy văn (HRUs) - sản xuất dòng chảy bề mặt và xói mòn và một hồ chứa. | 12 Modeling Phosphorus with the Generalized Watershed Loading Functions GWLF Model Elliot M. Schneiderman New York City Department of Environmental Protection Kingston NY CONTENTS History of Model Spatial and Temporal Predicting Infiltration and Predicting Phosphorus in Predicting Phosphorus Simulating Management and Simulating In-Stream Example Use of GWLF to Evaluate Accuracy of GWLF Comparison of Simulated to Measured Simulation of Runoff Volumes and Source Sensitivity Availability of References. 296 HISTORY OF MODEL DEVELOPMENT The Generalized Watershed Loading Functions GWLF model was originally developed at Cornell University by Douglas Haith and associates Haith and Shoemaker 1987 Haith et al. 1992 as an engineering compromise between the empiricism of export coefficients and the complexity of chemical simulation models Haith et al. 1992 . The GWLF approach conceptualizes the watershed as a system of different land areas hydrologic response units HRUs that produce surface runoff and erosion and a single groundwater reservoir that supplies base flow. 277 2007 by Taylor Francis Group LLC 278 Modeling Phosphorus in the Environment Dissolved and suspended substances . nutrients sediment in stream flow are estimated at the watershed outlet by loading functions that empirically relate substance concentrations in runoff sediment and base flow to watershed- and HRU-specific characteristics. The strength of this approach lies in its fairly robust hydrologic formulation of a daily water balance and in the ability to adjust loading functions through calibration and for specific watershed conditions to an ever increasing body of knowledge and data on the factors that influence the export of substances in stream flow from a watershed.
