During the first half of the last century periods of low water on the Rhine were distinctly more pronounced. Discharges were lower, and low flow periods lasted longer than in the past 50 years. The perception that low water occurs more often than in the past is not correct. However, water users are more affected, e.g. navigation, energy production, industry and agriculture.
This is the surprising result of the statistical analysis of historical discharge series carried out within the activities of the International Commission for the Protection of the Rhine (ICPR) and discussed in this year’s Plenary Assembly of the Commission in Solothurn (Switzerland). These findings may predominantly be attributed to the regulating influence of numerous reservoir lakes in the Alpine region. Also, the trend towards increasing annual precipitation observed in the Rhine catchment during the 2nd half of the 20th century may contribute to this fact (see Fact Sheet: Annex 1). However, since low flows directly impact water quality, ecology and uses, they will in future be monitored.
Please find here a summary of the report and the working results.