Comparing Navigability Of The Dutch Rivers Meuse And Waal Following The Pardé-Coefficient

Abstract

Prolonged droughts induced by climate change are a significant threat to inland shipping on Dutch rivers, particularly on the river Waal, a branch of the river Rhine. The anticipated shift to a more rain-dominated river, due to reduced meltwater from Alpine glaciers, may aggravate extreme low flow conditions, threatening the Waal's navigability. To improve the navigability in a rain-dominated river system, the Dutch government decided the transformation of the river Meuse into a confined river with seven weir-lock complexes. This study aims to compare the discharge regimes of both rivers to examine whether the river Waal turns into a rain-dominated system similar to the river Meuse, which may justify weir-lock complexes in the Waal as a potential solution. Analyzing 100 years of discharge data at Lobith, using the Pardé coefficient, shows that the characteristics of the Waal's runoff regime are shifting from a mixed-river towards a more rain-dominated river. Future climate projections indicate more pronounced extremes in runoff regimes, emphasizing the changing nature of the river Waal. While becoming more rain-dominated, the Waal's discharge regime is not expected to match the Meuse's before 2085.