Analysis of the impacts of coal mining on baseflow changes under the Budyko framework: A case study of Northern Shaanxi, China

Abstract

Coal mining alters the regional and local hydrogeological conditions and subsurface parameters, significantly impacting the hydrological cycle. Baseflow is particularly sensitive to changes in subsurface parameters and hydrogeological conditions. Therefore, studying the impact of coal mining on baseflow is crucial for understanding its effects on the water cycle. In this paper, 9 segmentation methods are used to separate the baseflow, after the applicability analysis, the Chapman-Maxwell and Boughton-Chapman separation methods were used. The Mann-Kendall and Pettitt tests are employed to determine the mutation years of baseflow. Finally, within the Budyko framework, the elasticity coefficient is calculated to estimate the changes in baseflow attributed to variations in precipitation, potential evapotranspiration, and underlying surface index. The results indicate that: (1) Based on the comparison of results and error analysis, we conclude that the Chapman-Maxwell separation method and the Boughton-Chapman separation method are the most suitable for the typical basins in the Shaanxi mining area. (2) During the study period, baseflow experienced a mutation in the late 1990s and showed an overall declining trend. (3) There is spatial heterogeneity in the influence of coal mining activities on baseflow, which has a negative impact. The change of base flow after mutation is −2.86 × 10⁸ m³.