Global water stress assessment for karst regions in a changing world with the development and application of a large-scale karst water resource model

Supported by

DBU(Link)

Duration

2024 - 2027

Project description

Karst aquifers are an important source of drinking water worldwide. According to studies, karst aquifers supply around 20 - 25 % of the world's population with drinking water. In some European countries and Alpine regions, karst groundwater even supplies over 50 % of the respective populations. However, in times of global change caused by climate change, population growth and human activities, not only is the pressure on karst water resources growing, but also the dependence on them. In order for decision-makers and stakeholders to prepare for current and future groundwater stress, or even groundwater scarcity, an understanding of the impacts of climate change, land use and population growth on water resources in karst areas is fundamental. Although great progress has already been made in large-scale groundwater stress risk assessment, large-scale hydrological models neglect the specificities of karst aquifers, which severely affects the applicability of said simulation models for groundwater resource management.

Karst landscapes are formed by the weathering of carbonate rock and are characterized by the strong surface and subsurface heterogeneity of flow and storage processes. This leads to preferential groundwater flow along the highly permeable pipe system and the delayed drainage of the low-permeability rock matrix as well as the interaction of both compartments. The described complexity poses a major challenge for the modeling of karst systems and results in a lack of reliable forecasts on the global availability of karst water resources with regard to current and future climate and population developments.

The overall aim of this PhD project is to fill this research gap and to develop a global groundwater model specifically for karst regions in order to reliably determine the current and, coupled with climate scenarios, future availability of water resources in karst areas. In order to identify regions threatened by water scarcity, the current and future water demand will also be taken into account. The basis for this work is a large-scale model for estimating groundwater recharge in karst regions and a karst groundwater model, which has so far mainly been used on a catchment scale. By means of model performance tests, sensitivity analyses and plausibility checks, as well as comparisons with common global simulation models that do not take into account the heterogeneity of karst systems, the reliability of the model is to be tested and verified. The model can then be used to estimate current and future water resources in the world's karst regions. The large application scale of the model should enable decision makers to assess the risks of climate change and population growth on karst water resources and to take necessary measures in the context of current and future karst water resource management. From a scientific point of view, this work aims to enrich research in the field of karst hydrology by presenting a novel model that seeks to address the challenges of reliable karst system modeling by taking into account both the need for realistic karst process representation and the required availability of input data.

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