During the initial development of a deposit of raw materials, the pumping out of ground water can lead to a lowering of the groundwater level. Water abstractions during extraction of the natural resources may also be necessary e. g. to keep shafts or excavation pits dry. This so-called sump and mine water is treated in compliance with the permit conditions, purified, re-infiltrated, reused (if necessary), e. g. to maintain wetland biotopes, or discharged into surface water without further use.
The use of water by the mining industry is associated with consequences for the water balance. Environmental impacts can result from, among other causes, the change in the groundwater level, the flow rate of water bodies and the introduction of drainage and mine water into surface waters.
Water abstraction in the natural resources sector by state in 2016 (in 1,000s of m³)
In the underground mining of potash and rock salt, raw salt is usually extracted by means of drilling and blasting. However, salt can also be extracted in a brine plant, where fresh water is introduced into soluble (salt) rock by means of a borehole, resulting in the creation of chambers filled with salt water. The salt-saturated water (so-called brine) is then conveyed to the surface via another pipeline. The salt is ultimately extracted when the brine evaporates.
The Water Resources Act (Wasserhaushaltsgesetz), which came into force in 1960, stipulates that water may only be extracted from groundwater and surface waters if there is a permit regulating this use in a manner that is specific in terms of type and extent. An EU-wide legal framework for the protection of water and groundwater was created in 2000 with the Water Framework Directive (EU) 2000/60/EC of October 23, 2000 (WRRL). The WRRL stipulates (inter alia) that the costs of water services (including certain water abstractions) and environmental and resource-related costs are covered by the polluter-pays principle.3 Water abstractions must also be checked for compli- ance with the general environment targets of the WRRL. If the volume of ground or surface water abstracted exceeds certain thresholds, environmental impact assessments must be carried out for the projects concerned.
The implementation of the WRRL into national law took place in Germany through the Water Resources Act, which regulates the protection and use of surface and groundwater at national level. Water abstraction procedures are subject to the reservation on the granting of permission by the water authorities. The water laws of the Federal States supplement and concretise the federal water laws. They also determine the amount of water abstraction charges, if such charges are levied by the Federal States.