Varying effects of mining development on ecological conditions and groundwater storage in dry region in Inner Mongolia of China

Abstract

Considerable efforts have been made to understand negative impacts of mining on vegetation conditions for humid regions, while little attention has been paid to impacts of mining in dry regions on ecological conditions and groundwater in an integrated way. A case study including two mines in Inner Mongolia of China was conducted to reveal varying influences of mining on ecology and groundwater under various development phases of the mines during 2002 and 2015. Three such phases were defined based on impacts of mining-induced groundwater variances on vegetation conditions: damaging phase, post-damaging phase, and restoration phase. In the damaging phase, increased (by 341% and 166% in Baiyin and Shengli Mine respectively) vegetation greenness due to drained groundwater irrigation and associated groundwater storage drawdown (by 206% and 60% in Baiyin and Shengli Mine respectively) were identified. The post-damaging phase can be characterized by reduced irrigation due to shutting down of groundwater drainage, causing sharp degradation of vegetation (by 165% (74%)) and recharging of the groundwater storage (by 202% (126%)) below 200 cm depth in Baiyin (Shengli) Mine. And the restoration phase is associated with the termination of the mining and related extraction of groundwater, featured by increased vegetation greenness (by 277%) and groundwater storage (by 196%) in Baiyin Mine. Besides, we found vegetation restoration is 1-year ahead of groundwater restoration. Although the withdrawal of groundwater in the damaging phase boosted thrives of vegetation, mining-induced groundwater depletion and damaged hydrogeological structure have far-reaching implications for local water resources and the living condition of groundwater-dependent vegetation in drylands, which may raise risks of irreversible vegetation degradation and subsequent desertification in long-term droughts.