Simulation Study on Nitrogen Pollution in Shallow Groundwater in Small Agricultural Watersheds in the Huixian Wetland
In this study, we investigated the influence of different simulations on the transport of shallow groundwater nitrogen in the Mudong River watershed of the Huixian Wetland, a karst wetland. Based on GMS (Groundwater Modeling System) software, the equivalent porous media model was used to simulate th...
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MDPI AG
2022-11-01
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| Series: | Water |
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| author | Zupeng Wan Junfeng Dai Linyan Pan Junlei Han Zhangnan Li Kun Dong |
| author_facet | Zupeng Wan Junfeng Dai Linyan Pan Junlei Han Zhangnan Li Kun Dong |
| author_sort | Zupeng Wan |
| collection | DOAJ |
| description | In this study, we investigated the influence of different simulations on the transport of shallow groundwater nitrogen in the Mudong River watershed of the Huixian Wetland, a karst wetland. Based on GMS (Groundwater Modeling System) software, the equivalent porous media model was used to simulate the transport of total nitrogen under different conditions in the study area. Two years of field monitoring data in the study area provided the input for the modeling. The SWAT (soil and water assessment tool) model was used to divide the study area into sub-basins. The initial concentration flux index W is first introduced in the equivalent porous medium model to calculate the initial concentration. The simulation results showed the difference between the simulated and monitored values of total nitrogen concentration was between 20% and 40% in 22.2% of the cases, and less than 20% in 66.7% of the cases, indicating that the solute transport model has good applicability in the Huixian Wetland. Parameter sensitivity analysis showed that fertilizer application was the main factor influencing total nitrogen. A 25% reduction in fertilizer application reduced total nitrogen emissions by 31.5% in sub-basin S3 and 22.5% in sub-basin S4. These reductions were greater than the abatement effect of changing land cover and managing river pollution. The pollution plume of total nitrogen was reduced by 38.5% in the southern part of sub-basin S3 (Mudong Lake) and by 40.2% in the western part of sub-basin S4 (Blacksmithing Village). The average concentration was reduced by 2.04 mg/L and 1.22 mg/L, respectively. This study shows that reasonable control of double-season rice nitrogen fertilizer application and appropriate land cover modification can help reduce total nitrogen emissions from wetlands in the Li River watershed and ensure the sustainable development of the local economy and groundwater. |
| first_indexed | 2024-03-09T17:56:28Z |
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| language | English |
| last_indexed | 2024-03-09T17:56:28Z |
| publishDate | 2022-11-01 |
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| series | Water |
| spelling | doaj.art-b7131e75c5e04e6992c4848344088dd62023-11-24T10:20:50ZengMDPI AGWater2073-44412022-11-011422365710.3390/w14223657Simulation Study on Nitrogen Pollution in Shallow Groundwater in Small Agricultural Watersheds in the Huixian WetlandZupeng Wan0Junfeng Dai1Linyan Pan2Junlei Han3Zhangnan Li4Kun Dong5College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541004, ChinaGuangxi Key Laboratory of Environmental Pollution Control Theory and Technology, Guilin University of Technology, Guilin 541004, ChinaCollege of Environment and Resources, Guangxi Normal University, Guilin 541004, ChinaCollege of Environmental Science and Engineering, Guilin University of Technology, Guilin 541004, ChinaCollege of Environmental Science and Engineering, Guilin University of Technology, Guilin 541004, ChinaCollege of Environmental Science and Engineering, Guilin University of Technology, Guilin 541004, ChinaIn this study, we investigated the influence of different simulations on the transport of shallow groundwater nitrogen in the Mudong River watershed of the Huixian Wetland, a karst wetland. Based on GMS (Groundwater Modeling System) software, the equivalent porous media model was used to simulate the transport of total nitrogen under different conditions in the study area. Two years of field monitoring data in the study area provided the input for the modeling. The SWAT (soil and water assessment tool) model was used to divide the study area into sub-basins. The initial concentration flux index W is first introduced in the equivalent porous medium model to calculate the initial concentration. The simulation results showed the difference between the simulated and monitored values of total nitrogen concentration was between 20% and 40% in 22.2% of the cases, and less than 20% in 66.7% of the cases, indicating that the solute transport model has good applicability in the Huixian Wetland. Parameter sensitivity analysis showed that fertilizer application was the main factor influencing total nitrogen. A 25% reduction in fertilizer application reduced total nitrogen emissions by 31.5% in sub-basin S3 and 22.5% in sub-basin S4. These reductions were greater than the abatement effect of changing land cover and managing river pollution. The pollution plume of total nitrogen was reduced by 38.5% in the southern part of sub-basin S3 (Mudong Lake) and by 40.2% in the western part of sub-basin S4 (Blacksmithing Village). The average concentration was reduced by 2.04 mg/L and 1.22 mg/L, respectively. This study shows that reasonable control of double-season rice nitrogen fertilizer application and appropriate land cover modification can help reduce total nitrogen emissions from wetlands in the Li River watershed and ensure the sustainable development of the local economy and groundwater.https://www.mdpi.com/2073-4441/14/22/3657non-point source pollutiontotal nitrogenGMS modelkarst wetland |
| spellingShingle | Zupeng Wan Junfeng Dai Linyan Pan Junlei Han Zhangnan Li Kun Dong Simulation Study on Nitrogen Pollution in Shallow Groundwater in Small Agricultural Watersheds in the Huixian Wetland Water non-point source pollution total nitrogen GMS model karst wetland |
| title | Simulation Study on Nitrogen Pollution in Shallow Groundwater in Small Agricultural Watersheds in the Huixian Wetland |
| title_full | Simulation Study on Nitrogen Pollution in Shallow Groundwater in Small Agricultural Watersheds in the Huixian Wetland |
| title_fullStr | Simulation Study on Nitrogen Pollution in Shallow Groundwater in Small Agricultural Watersheds in the Huixian Wetland |
| title_full_unstemmed | Simulation Study on Nitrogen Pollution in Shallow Groundwater in Small Agricultural Watersheds in the Huixian Wetland |
| title_short | Simulation Study on Nitrogen Pollution in Shallow Groundwater in Small Agricultural Watersheds in the Huixian Wetland |
| title_sort | simulation study on nitrogen pollution in shallow groundwater in small agricultural watersheds in the huixian wetland |
| topic | non-point source pollution total nitrogen GMS model karst wetland |
| url | https://www.mdpi.com/2073-4441/14/22/3657 |
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