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| Parameter sensitivity and applicability analysis of AnnAGNPS model in Qifeng River watershed in the southwest Karst area of China |
| Received:October 10, 2019 |
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| KeyWord:Southwest Karst area;AnnAGNPS model;parameter sensitivity;applicability evaluation;runoff simulation |
| Author Name | Affiliation | E-mail | | LIANG Li-ying | College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541006, China | | | GAO Zhen-gang | College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541006, China | | | LIU De-cai | College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541006, China | | | YAN Xiao-yu | College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541006, China | | | ZENG Hong-hu | College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541006, China
Guangxi Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area, Guilin 541006, China | zenghonghu@glut.edu.cn | | LIU Zheng | Chemistry and Bioengineering, Guilin University of Technology, Guilin 541006, China | 1986034@glut.edu.cn | | QIN Li-tang | College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541006, China | | | LIANG Yan-peng | College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541006, China | |
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| Abstract: |
| To explore the applicability of the agricultural non-point source AnnAGNPS model in the Qifeng River small watershed in the southwest Karst area, a differential sensitivity analysis(DSA)method was used to analyze the sensitivity of the parameters. The sensitivity index method was used to evaluate the sensitivity level of the parameters. The parameters of the model were adjusted manually by a trialand-error method. The evaluation index, the coefficient(R2), the Nash coefficient (ENs), and the relative deviation(Re)were used to evaluate the performance of the model. The applicability of the model to the Qifeng River small watershed in the Karst area was tested. When the critical source area(CSA)and minimum source channel length(MSCL)values were varied, a CSA of 20 hm2 and MSCL of 200 m were found to comprehensively describe the situation in the Qifeng River Basin. The results of the parameter sensitivity analysis showed that the most sensitive parameter for runoff simulation was the number of runoff curves(CN). Compared with non-Karst areas, the most sensitive parameters affecting surface runoff were the same, although the values were larger than those in non-Karst areas. The most sensitive parameter for sediment, total nitrogen, and total phosphorus simulation was soil erosion factor. The simulation results showed that the AnnAGNPS model could simulate the surface runoff of the Qifeng watershed. The R2, ENs, and Re of the simulation of runoff on the monthly scale were 0.962, 0.831, and -14.94%, respectively, but 0.716, 0.946, and -13.69%, respectively, on the daily scale. Owing to the high leakage of the Karst system and the instantaneous exchange of groundwater and surface water, the simulation accuracy at the daily scale was low. The study indicates that the AnnAGNPS model is suitable for non-point source pollution load simulation in the Qifeng River Basin of Guilin City in the southwest Karst area. |
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