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Preliminary study on distributed erosion-type non-point source pollution model |
Received:July 02, 2022 |
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KeyWord:soil erosion;non-point source pollution;distributed model;adsorbed phosphorus;hilly and mountainous area;Three Gorges Reservoir region |
Author Name | Affiliation | E-mail | ZHU Kaihang | School of Environment, Beijing Normal University, Beijing 100875, China | | CHEN Lei | School of Environment, Beijing Normal University, Beijing 100875, China | chenlei1982bnu@bnu.edu.cn | WANG Yiwen | School of Environment, Beijing Normal University, Beijing 100875, China | | LIU Guowangchen | School of Environment, Beijing Normal University, Beijing 100875, China | | YAN Xiaoman | School of Environment, Beijing Normal University, Beijing 100875, China | | GUO Chenxi | School of Environment, Beijing Normal University, Beijing 100875, China | | ZHANG Liang | Innovation Academy for Precision Measurement Science and Technology, CAS, Wuhan 430077, China | | SHEN Zhenyao | School of Environment, Beijing Normal University, Beijing 100875, China | |
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Abstract: |
Soil erosion and non-point source pollution are serious issues in hilly and mountainous areas. Studying the synergistic process mechanism is important to enable environmental improvements in hilly and mountainous areas. There is limited knowledge of erosion-type non-point source pollution in hilly and mountainous areas. In particular, refined evaluations need to be further improved. In this study, a distributed erosion-type non-point source pollution model was developed. By coupling multiple key process of erosion-type non-point source pollution, the mechanism of this pollution process was accurately described from the perspective of source, flow, and sink. A confluence module based on an optimization algorithm was developed to solve technical problems, such as low execution efficiency, of the distributed model. The new model was used to evaluate the temporal and spatial evolution of erosion-type non-point source pollution in the Jinglinxi watershed of the Three Gorges Reservoir region, and to evaluate the effects of returning farmland to forest, fertilizer reduction, slope modification, and coastal buffer zone on erosion-type non-point source pollution. The results indicated that the average load of introduced sediment, adsorbed phosphorus, and dissolved phosphorus in Jinglinxi watershed was 17.23 t·hm-2, 1.22 kg·hm-2 and 0.56 kg·hm-2, and the annual average amount of introduced sediment, adsorbed phosphorus, and dissolved phosphorus was 9 032.2 t·a-1, 601.3 kg·a-1 and 541.7 kg·a-1, which accounted for 54.32%, 50.87%, and 72.99% of the total load respectively. The load of adsorbed phosphorus for different land uses was ranked as sloping farmland > forest land > paddy field. The load of dissolved phosphorus was ranked as sloping farmland > paddy field > forest land. These findings indicated that the priority control area of erosion-type non-point source pollution differed from that of traditional agricultural non-point sources. The coastal buffer zone was best in reducing erosion-type non-point source pollution, with reductions of 25.01% and 26.22% in the amount of sediment and adsorbed phosphorus entering the watershed, respectively. The new model better simulates the erosion-type non-point source pollution and the reducing effect of prevention measures, and provides a basis for accurate analysis of the process mechanism of erosion-type non-point source pollution and optimized prevention measures. |
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