| Title | “Heat Below the City†– City-Wide Groundwater Temperature Measurements Reveal Underground Urban Heat Islands in Vienna (Austria) |
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| Authors | Cornelia STEINER, Christian GRIEBLER, Eszter NYEKI, Eva KAMINSKY, Constanze ENGLISCH, Christine STUMPP |
| Year | 2024 |
| Conference | Stanford Geothermal Workshop |
| Keywords | groundwater temperatures, urban heat island effect, shallow geothermal energy, hydrogeology, Vienna |
| Abstract | Summer periods of warm weather become longer and hotter causing “Urban Heat Islands†in large cities. Rising temperatures do not stop at the surface, but migrate into the underground, where infrastructure amplifies the increase of groundwater temperatures. In order to be able to quantify this ongoing process and predict future temperature developments, a sound data basis is necessary. Goal of this study was to increase the data density for the urban shallow aquifers of Vienna. Therefore we measured groundwater temperature and level in more than 800 wells and analyse this data statistically. To document the warmest and coldest conditions, measurements took place in one week each in October (2021) and April (2022). In total, groundwater temperatures in 1 m depth intervals and groundwater level were measured. The groundwater temperatures documented in our field studies vary between 6.9 °C and 30.6 °C. The highest temperatures were detected in close proximity to possible heat sources and a rapid drop in temperature with increasing distance could be demonstrated. Based on the collected data, temperature maps for both measurement dates and for different depth-intervals were derived, and display the underground urban heat islands in Vienna. The temperature maps enable the estimation of the potential for sustainable heating and cooling with groundwater in the capital of Austria. |