Future developments in water quality at surface water intake points for drinking water supply constitute the key climate-change associated risk for the drinking water sector. This was a conclusion of a risk analysis conducted for the BTO Climate-Proof Water Sector theme group.
In the current project we research the impact of climate change and societal developments on water quality at three intake points.
Testing future concentrations of special-attention contaminants
We have estimated the presence at the intake points of future concentrations of selected special-attention contaminants (e.g., pesticides, pharmaceuticals and industrial substances), and tested them against water quality standards. Water quality prognoses were made on the basis, on the one hand, of scenarios of contaminant emissions resulting from societal developments and, on the other, of river flow-level scenarios from the Delta Programme. This involved the use of existing datasets.
Target values are already exceeded in today’s climate
Understanding the impact of climate change and other societal developments on raw water quality is important in order to underpin recommendations for an optimal protection of sources, and to develop an appropriate treatment strategy.
The results of the water quality prognoses are summarised in an infographic. It shows, for each modelled contaminant, how often the raw water standard for pesticides (0.1 µg/l; Drinking Water Regulations), or the ERM target value for pharmaceuticals (0.1 µg/l) is exceeded at Rijkswaterstaat measuring points in each of the scenarios considered.
In general terms, the research results show that, in today’s climate, standards or target values are already being exceeded on a large scale in the Rhine and Meuse rivers, particularly with regard to radiocontrast agents. In addition, specific exceedances occur at individual locations.
Thanks to high purification efficiencies, most contaminants are sufficiently removed from the raw water, both today and in the future scenarios. The exceptions are acesulfame K at Leiduin (not measured at other locations), metformin at Kralingen, and amidotrizoic acid at Leiduin, Kralingen and (to a lesser degree) Heel. If the purification efficiencies for these contaminants are not improved, they will be increasingly detected in drinking water. For some contaminants this is already the case, even if no standards have been exceeded.