DEVELOPMENT OF A DYNAMIC ADSORBED PHOSPHORUS POLLUTION LOAD MODEL AND ITS APPLICATION TO THE JIALING RIVER BASIN, CHINA

摘要

Soil erosion model is a foundation for the estimation of adsorbed non-point source (NPS) pollution load at catchment scales. Empirical models are useful for estimating soil erosion, particularly when only limited data are available. In all empirical models, the Universal Soil Loss Equation (USLE) or the Revised Universal Soil Loss Equation (RUSLE) is one of the most widely used models. However, the USLE or the RUSLE is only suitable for simulation of long-term averages of yearly soil erosion and not for simulation of continuous changes, in addition, the USLE and the RUSLE are directed towards on-site soil erosion, which makes them of limited to the assessment of off-site parts of soil erosion and sediment yield in a watershed level. In this research, a GIS-based dynamic and integrated model of yearly adsorbed NPS pollution load was developed according to the correlation between sediment yield and adsorbed NPS pollution load, where the continuous simulation model of yearly sediment yield was established by modifying the RUSLE. A case study from the Jialing River basin in China was presented to verify the developed model. Its temporal and spatial variations of adsorbed total phosphorus (TP) pollution load from 1998 to 2007 were estimated by geographic information system (GIS) techniques. Satisfactory simulation results were obtained, which validated the model presented in this paper to be reasonable.