SUPERVISOR: Christine STUMPP 

PROJECT ASSIGNED TO: Eva KAMINSKY 

The availability of sustainable water resources and the increasing energy need is one of our major challenges today. Climate change effects, urbanization with surface sealing and subsurface infrastructure, such as geothermal facilities, can contribute to an increasing groundwater temperature trend. The average groundwater temperature increase in Austria is +0.36 ±0.44 K per 10 years (1994-2013) (Benz et al. 2018) and even higher with +0.11 K per year for the city of Vienna (Götzl et al. 2020). Different studies in large cities observed urban heat islands (UHIs) in the subsurface with large quantities of energy. These subsurface UHIs could be used to supply inhabitants with geothermal energy as a major renewable energy source. Due to the use of the heat in the groundwater, this could have an additional reducing effect on UHIs. However, the link between the UHIs and urban activity’s is not yet sufficiently understood. Especially, the knowledge of the effect on the urban groundwater ecosystem and the groundwater quality is lacking. 

Therefore, the project Heat below the city is founded by the WWTF (Wiener Wissenschafts-, Forschungs- und Technologiefonds) to study the observed groundwater temperature increase below the city Vienna with an interdisciplinary approach. The interplay of shallow geothermal energy use, thermal pollution of the shallow subsurface, hydrological, physico-chemical and biological processes and conditions in Vienna’s shallow groundwater bodies will be evaluated in cooperation with the project partners at the Geological Survey Austria (Department Hydrogeology & Geothermal Energy) and the University Vienna (Department Functional and Evolutionary Ecology).

This thesis is part of the project Heat below the city and focuses on

(i) the application of multi-tracer approaches (environmental tracer as stable isotope analysis combined with geochemistry data) to study the groundwater body functioning below Vienna, and

(ii) short term and long term time series analysis of water temperature and chemistry records to improve our understanding of groundwater temperature variability and UHI and its effect on groundwater quality.

In course of this research, field work (groundwater sampling) will be applied with data analysis and modelling. Modern and future oriented methods within trend analysis, numerical simulations and statistical analysis will allow quantifying the impact of increasing water temperature and its effect on water quality in urban areas. 

The topic is directly connected to study the vulnerability and connectivity of the environmental groundwater body, which is related to the HR21 Research Cluster 1 and 4. 

  

1 Benz SA, Bayer P, Winkler G, Blum P (2018) Recent trends of groundwater temperatures in Austria.
Hydrol Earth System Sci 22: 3143-3154.

2 Goetzl G, Dilger G, Grimm R, Hofmann K, Holecek J, Cernak R, Janza M, Kozdroj W, Klonowski M,
Hajto M, Gabriel P, Gregorin S (2020) Strategies for fostering the use of shallow geothermal energy
for heating and cooling in Central Europe – results from the Interreg Central Europe project
GeoPLASMA-CE, Proceedings World Geothermal Congress 2020.