Response of the intensity of human activity to water quality in ecologically fragile karst areas

In order to quantitatively analyze the effect of human activity on the water quality of basins, we selected eight indicators considering the area’s socialization degree, economic development, and ecological governance and protection, including population, fertilizer application, and livestock breeding. Based on the GIS spatial analysis method, we proposed and constructed a quantitative model of the impact of human activity on water quality in basins (QMIHAW). The results show that: (1) In the study area, the intensity of human activity was mainly weak and moderate, the impact strength of human activity was mainly weak and there were no areas with extremely strong impact. Within the study area the intensity and impact strength of human activity were the strongest in the Nayong River Basin and weaker in the Zhangwei River Basin. (2) At each sampling point, water quality had a good response relationship with the impact of human activity. With the exception of the Zhangwei River Basin, the impact strength of human activity and the water quality comprehensive pollution index were positively correlated. Therefore, the QMIHAW model is reasonable and can quantitatively reflect the impact strength of human activity on the regional ecological environment, especially river water quality within the study area.