Assessment and forecast of changes in the ecological conditions of the underground and surface hydrosphere within Donbass at the post-mining stage

Abstract

The Donbass coal industry is currently undergoing critical changes due to post-mining of the coal industry in the context of the armed conflict in eastern Ukraine and the predominant use of autorehabilitation flooding of unprofitable mines (“wet conservation” scheme). The massive decommissioning of mines in developed (old) coal-mining areas disrupts the relatively balanced ecological state of the natural and man-made technogenic geosystem (TGS) “mining complex of the coal mine-environment”, primarily due to irreversible changes. According to our estimates, the following ecological and man-made changes in the underground and surface hydrosphere of Donbass, subject to further implementation of the modern post-mining scheme, include the following: 1) regional intensification of underground aquifers pollution in the zone of active water exchange (AWE – predominant formation of fresh water) and surface water bodies (rivers, lakes, reservoirs, domestic wells, springs) by heavy and toxic chemical elements; 2) deterioration of bioproductivity in large areas “mining complex – environment”; 3) development of areas of flooding and inundation of lands with acceleration of pollutants migration into the underground and surface hydrosphere; 4) additional subsidence of the earth's surface due to water saturation of previously drained rocks and reducing their compressive strength; 5) violation of the hydrological (balance, level, hydrochemical) regime of the river network in places of interception of surface runoff in areas of the earth’s surface additional subsidence and the destruction of regional watersheds; 6) formation of persistent pollution areas of bottom sediments of surface water bodies with toxic chemical elements and organic compounds that contribute to the long-term deterioration of water-ecological parameters of surface runoff and the first from the surface of the groundwater aquifer; 7) regional deterioration of ecological and hygienic safety of drinking water supply systems of cities and settlements within the Donbass coal zone.

Keywords

• post-mining
• underground and surface hydrosphere
• pollution
• flooding
• overmoisturing
• water resistance layers