Evolution of water environment under the influence of mining in Yanzhou coalfield

Based on the remote sensing images of Yanzhou coalfield from 1990 to 2018, the modified normalized difference water index(MNDWI) method is used to extract the water body information of Yanzhou coalfield, and the temporal and spatial evolution of the water body in Yanzhou coalfield is analyzed.Based on landscape ecology method, the number of patches, landscape shape index, fractal dimension index of area weighted mean and mean patch area are selected to quantitatively study the evolution of water body in Yanzhou coalfield from the aspects of frag mentation, shape change and man-made interference.The results show that coal mining activities have led to an increase in the area of subsided water, increasing from 214.38 hm² in 1990 to 2 717.73 hm² in 2018, an increase of nearly 10 times.The shape of the water is increasingly irregular, which is enhanced by the disturbance of human activities, especially by mining activities.The plaque fragmentation of water bodies is reduced and continuous type is enhanced, the shape of water plaques is more and more complex, and the degree of influence by mining activities is increased.