The European Water Framework Directive (EC 2000) aims at reaching a good ecological status of the European rivers. One of the problems in water management that hinder reaching this goal is water scarcity. Water scarcity often leads to higher water temperature, worse water quality conditions and a reduced flow or even desiccation of river beds. These impacts are expected to increase through climate change. Higher water temperature decreases the oxygen supply and increases organic loading which affects ecosystem composition and is therefore undesirable. A lower discharge reduces the dilution of wastes, therewith increasing the concentrations of pollutants (Beniston et al. 2002). And a low flow, no flow or even desiccation affects the river flora and fauna. Low flows may result in several types of problems to society, e.g. lack of water for drinking water supply, irrigation, industrial use and power production, and hindrance to navigation (Booij et al. 2006). For these reasons, the EU Blueprint (EC 2012) puts specific focus on water demand management. The River Meuse regularly encounters situations with low flow. In these situations the contribution of the River Rur, a tributary of the River Meuse, to the discharge is significant. The Rur has a series of dams and the discharge can, as a result, be regulated to a high degree. Moreover, the deep lakes behind the dams contain cool water that may have a cooling effect on the Meuse water in summertime. Plans exist to divert water from the Rur to former brown coal quarries in mid-flow situations of the Rur (5-15 m3/s). This diversion may have substantial effects on the discharge of Rur and Meuse and significant effects on the water temperature and water quality, not only for the Rur but also at the intake points for drinking water production from the Meuse. This study in this way provides the necessary first step to estimating the influence of the Rur on the Meuse and to developing a more in-depth research study on the relationships between water quality, water temperature and discharge in situations of low flow for the whole Meuse catchment.