Surface water

In order to describe the water status, water bodies are categorized into status classes. Chemical status bases on the concentrations of particularly hazardous pollutants. These are compared with the environmental standards prescribed and the status is categorized as good or not good. For the ecological status, various animal and plant communities, the so called biological quality components, are analyzed, so that the water status, depending on their compatibility with the natural conditions, can be categorized as high, good, moderate, poor or bad. For the overall evaluation, a "one out – all out" principle is applied. This means, if one single component displays bad assessment results, the overall assessment shall be categorized as bad as well – even if all other components should show a better status – and consequently, this water body shall not achieve the objective required.

Until 2015, 13% of all surface waters shall achieve at least good ecological status, resp. good ecological potential. With regard to the observation of the chemical status the current different assessment has to be considered. The chemical status shall be displayed on a map according to the applicable law. The federal states Nordrhein-Westfalen and Hesse have recorded the status in due consideration of the Daughter Directive Environmental Quality Standards (2008/105/EG).

Groundwater

For the assessment of the quantity status of groundwater, the altitude of the groundwater level is considered a main criterion. For the assessment of chemical status, the parameters nitrate and pesticides, as well as regionally diverse threshold values are considered. The provisions of the Groundwater Directive (2006/118/EG) are decisive thereby. Groundwater bodies are categorized in two status classes: good or bad. Regarding the separate quality components, the "one out - all out" principle is applied, similarly to the surface waters. If a significant exceedance of a limit or threshold value in a groundwater body is determined, it means that this groundwater body features a bad status. Moreover it is necessary to observe the trends starting from defined pollutant concentrations.

The assessment has led to the conclusion that 143 out of 144 groundwater bodies (99,8 % of total area) show good quantitative status and 105 groundwater bodies (58 % of total area) show good chemical status. Out of 39 groundwater bodies in bad chemical status, 7 show a significant increasing trend of pollution concentration. This increasing concentration can mainly be resulted from nitrate pollutions coming from diffuse sources.

The result reveals that the quantitative problems of groundwater in the river basin district of Weser are well behind the problems regarding the water quality, which are mainly referred to nitrate pressures coming from the diffuse pollution sources.