Water is a vital resource and the protection of surface and ground water is a core element of environmental policy. However, both water bodies and and groundwater are continuously polluted by human intervention without a complete compensation of damages. According to the categorization of the European Water Framework Directory, the chemical and ecological condition of water bodies is affected as well as the chemical and quantitative state of ground water. Some examples are the pollutant and nutrient burden caused by industrial agriculture and changes like the straightening and deepening of rivers, as well as the impact of oil and plastic on marine fauna and flora. Decline of fish population, health impacts on human beings, shrinking of recreation and leisure values and rise of flooding are among the consequences of such interventions.1
Such damages can be regarded as the environmental and resource costs of water usage, which to calculate has recently moved into the center of attention in the course of applying the European Water Framework Directory. The damages can also be understood as the gap between the current state and a good ecological condition of water bodies. The damage categories mentioned are part of the environmental costs. In 2010, only 10 % of surface waters were in good ecological condition according to the European Water Framework Directory.
In most cases this was caused by excessive nutrient inputs and severe changes of the hydromorphology regarding the watercourses.