Mitigating the effect of drought on groundwater levels in the east of The Netherlands

Abstract

Due to climate change, a new water management policy is considered in the Netherlands. The shift towards greater extremes in both wet periods and dry periods requires a more dynamic policy. It is investigated what effect the placement of a permanent water barrier in the Rijnmond has on the water levels in the Rhine branches, and if this can be an opportunity to help the drought prone area in the east of the Netherlands.This study shows that replacing the Maeslantkering with a permanent barrier has no influence on the water levels upstream of Nijmegen in the Waal at average to low Rhine discharges (2000 - 600 m^3/s), and thus has no effect on the water distribution at the Pannerdensche Kop. If the fresh water demand to stop the salt wedge is eliminated, a different water distribution over the Rhine branches is possible, but structural changes at the bifurcation point have to be made in order to achieve this. River water can be used to supply the east of the Netherlands with water. In this study, three options to do so are examined. The most promising options of these is placing a pumping station in the Rhine nearby Lobith and supplying the streams in the area with water, many of which fall dry in summer. From there, the water can be used for irrigation, infiltration, and other fresh water demands, relieving the stress on the groundwater during dry spells. Building a permanent storm surge barrier is not a requirement, but because it increases the navigability of the Waal river, water can be extracted more often with a permanent barrier. A solution to combat drought in the east of the Netherlands seems to be more urgent than a solution to mitigate sea level rise. However, a permanent barrier can help in mitigating the effect of drought on groundwater levels in the east of the Netherlands by allowing for more flexibility in using river water extraction.