Every Drop Counts

Abstract

More and more frequently, the streamflow of the Rhine becomes dangerously low. Drought is exacerbated by climate change, glaciers are melting at rapid rates. These problems affect the functions and ecosystems around the Rhine. The Rhine accounts for two-thirds of all inland waterway transports across Europe and thus experiences severe economic consequences when the streamflow gets low. Goods can no longer be shipped, and industries and agriculture depend on this water supply. More importantly, the Rhine also serves as a source of clean drinking water. With growing urbanisation, industries and agriculture along the Rhine, the pressure on the drinking water supply grows. The chances of periods of drought are increasing. Problems like salinisation, water pollution, damage to ecosystems and rising water temperatures will only become more apparent in the future.

In Every Drop Counts, the vision for the Rhine is to become a connected green-blue infrastructure. This proposal combines nature-based solutions that form a coherent system on a small scale and a green-blue infrastructure that works in a cross-border approach. Together they provide habitat diversity, mitigate drought, and human-nature interactions. The riverscape of the Rhine has to deal with more extreme fluctuations in water levels and more intense periods of drought and flooding. To battle the problems the Rhine faces, this thesis attempts to create a pattern catalogue focussing on drought-mitigating design strategies. These strategies are implemented around the Rhine to create a riverscape able to deal with streamflow fluctuations.

The design strategy will have other positive benefits besides a drought-resilient riverscape. Flooding of urbanised areas can be avoided, and living and recreational spaces will stay functional during periods of drought. Industries, agriculture and thus the economy around the Rhine will remain stable during periods of drought, as water retention capacity will be increased and buffers can be implemented.
Habitat diversity will develop and improve biodiversity. The implemented green-blue infrastructure creates a connected structure of habitats where species can flourish. Part of this strategy will be restoring historic riverscapes, creating more space for the Rhine and bringing back old habitats that got lost during the reconstruction of the Rhine.

To create a functional riverscape during streamflow drought, the Rhine will have to use all available water throughout the seasons. To mitigate the drought problems, the urban and rural areas have to create a synergy where strategies are combined, and land is optimally used to develop a drought-mitigating strategy. For this, it is essential to know what each area around the Rhine offers and what type of drought-mitigating measures are most suitable to implement.

The nature-based solutions embedded in the green-blue infrastructure are combined into a drought-mitigating pattern catalogue. This multiscalar pattern catalogue can be filtered for different types of landscapes, land uses, and more requirements. This approach is tested on other design locations and leads to a selection of measures that apply to different landscapes. By implementing the green-blue infrastructure approach with nature-based drought-mitigating solutions in rural and urban areas, a functional riverscape during streamflow drought can be created.