Studies indicate that climate change may result in increases in frequency and intensity of summer droughts in the Dutch river basins (Middelkoop et al., 2001). The impact of climate change on hydrology has been widely studied, and recently more and more attention has been paid to water quality (e.g. Van Vliet & Zwolsman, 2008). The impacts are particularly high on rain-fed rivers like the Meuse.
The river Meuse in Western Europe is a rain-fed river that is characterized by a highly variable discharge regime with commonly low discharges during summer and autumn, leading to a high sensitivity to droughts (De Wit et al., 2006). During these droughts, important river functions regarding the water quantity are (partly) disabled, such as water availability for agriculture and the extraction of water for domestic use.
Although there is a good knowledge of the effects of low discharges on the water quality of the Meuse river, the influence on the Lateral canal near the village of Heel, where water for drinking water supply is extracted, is unknown.
Regarding the Dutch part of the river Meuse basin, the water quality is monitored at several locations, including Eijsden and Heel. However, it is not known what the influences of side rivers and emissions on the Meuse between Eijsden and Heel on the water quality of the Meuse river are.
The objective of this internship is to perform an analysis of the water quality of the Meuse river near Eijsden and the Lateral Canal near Heel and to interpret possible differences between the results of these analyses, focusing on low river discharges.
This leads to the following main research question:
What is the influence of side rivers and direct emissions on the water quality of the Lateral Canal and how do low river discharges influence this?
In order to answer this main question, several sub-questions have been formulated:
- What are effects of low river discharges on the water quality during low discharge periods?
- What are influences of side rivers of the Meuse on the water quality for average hydrology and low river flows?
- What emissions on the Meuse river between Eijsden and Heel influence the water quality for average hydrology and low river flows?
To evaluate variations in water quality during low discharge periods, three situations will be investigated. First, a reference year will be plotted, with average substance concentrations for the whole year. Secondly, the averages for both the meteorological summer (in which a lower river discharge takes place) and winter (high river discharge) will be plotted. Variations in water quality during low discharge periods will be plotted as time series for the years in which low discharge occurs (2003, 2006). By statistically analyzing the differences between these situations, statements about possible significant differences can be made. The chosen substances are known to be discharged in large quantities between Eijsden and Heel. In addition to this the water supply company of Limburg (WML) selected fourteen pesticides, based on problem perception for the company.
References:
Middelkoop, H., Daamen, K., Gellens, D., Grabs, W., Kwadijk, J.C.J., Lang, H., Parmet, B.W.A.H., Schädler, B., Schulla, J., Wilke, K., 2001. Impact of climate change on hydrological regimes and water resource management in the Rhine basin. Climate Change 49: 105-128.
Van Vliet, M.T.H., Zwolsman, J.J.G., 2008. Impact of summer droughts on the water quality of the Meuse river. Journal of Hydrology 353: 1-17.
De Wit, M.J.M., Van den Hurk, B., Warmerdam, P.M.M., Torfs, P.J.J.F., Roulin, E., Van Deursen, W.P.A., 2006. Impact of climate change on low-flows in the river Meuse. Climate Change, DOI 10.1007/s10584-006-9195-2.