Water-quality map

A water-quality map allows one to determine the combined effects of emissions from various sources on the level of pollution in surface waters in the Netherlands. In specific instances it permits the calculation of the total toxic pressure in surface water, or offers insight into the impact of policy measures. A successful water map has to contain a broad range of data. This project contributed to fleshing out the map, and provided an overview of the availability, completeness and quality of the data needed to generate a comprehensive water-quality map in the future.

Feasibility and potential

Emissions of organic, microbial and chemical pollutants from multiple sources pollute surface water in the Netherlands. In order to effectively address this pollution, knowledge about the emissions and their dispersal is needed. The dispersal of various types of pollutants in Dutch surface water can be modelled using a hydrologic model of the Netherlands (in this case, the WFD Explorer). By combining emissions from different sources – i.e., wastewater treatment, industry water treatment, diffuse emissions from agriculture, and the contribution of cross-border rivers – an overview can be created of their combined effect on water quality in the shape of a so-called ‘water-quality map’. This makes it possible, for example, to calculate the total toxic pressure in a particular body of surface water, or the potential impact of different policy measures, like the extension of the treatment process at a wastewater treatment plant (WWTP). The success of the water-quality map depends however on the availability of data on the emissions, spatial distribution, transport and degradability of pollutants. This project modelled the dispersal of individual emissions of pollutants via WWTPs and cross-border rivers. For these sources, the emissions and resulting maps can be further analysed in follow-up projects. In addition, an overview was produced of the availability, completeness and quality of the data needed for a comprehensive water-quality map, and recommendations were made about how it can be realised in the future.