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| DOI：10.13522/j.cnki.ggps.2021471 |
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| Attenuation of Pollutants in Beipanjiang River Basin Calculated Using the InVEST Model |
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LI Wei, ZHAO Zulun, LYU Sisi, et al
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1.Institute of Mountain Resource, Guizhou Academy of Sciences, Guiyang 550001, China;
2.Department of Karst Research Institute, Guizhou Normal University, Guiyang 550001, China
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| Abstract: |
| 【Background and objective】Most catchments are able to decontaminate exogenous pollutants to some extent to maintain their ecological functions. This capability depends on many biotic and abiotic factors and varies spatiotemporally. Understanding this variation is important to improve catchment management but challenging. This paper proposes a new method to plug this gap.【Method】The model is based on simulating the dynamics of typical pollutants. By taking the Beipanjiang River basin as an example, we simulated the dynamics of total nitrogen (TN) and total phosphorus (TP) based on the measurement at the outlet of the basin in 2000, 2010 and 2020 using the InVEST model with the help of GIS, from which we analyzed their spatiotemporal variation and the underlying determinants. 【Result】The dynamics of TN and TP in 2000, 2010 and 2020 did not differ from each other noticeably, but a significant intra-year difference in spatial distribution of TN was found, where the minimum and maximum TN output per unit area in 2010 were 1.51 kg/hm2 and 5.21 kg/hm2, respectively. The average total TN flow rate in the catchments was more than 8 000 T/years, reduced by 120.76 T in the 20 years. The average total TP flow rate in the catchment was more than 1 200/t year, reduced 5.45 T in the 20 years, indicating that the ability of the basin to attenuate nitrogen and phosphorus has been improving over the 20 years. The areas with high TN and TP were in the upper and middle reaches of the basin, as well as in the proximity of urban areas, while those with low TN and TP were the flatten areas at the downstream of the basin. Excessive application of N and P fertilizers in croplands as well as the sewage in urban areas were the source of the pollutants, which are too much for the basin to decontaminate. In addition, changes in climate and land use also alert the capacity of the basin to attenuate the contaminants． |
| Key words: river basin; self-purification; InVEST model; Beipanjiang river |
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