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| Titel |
Development of monitoring and modelling tools as basis for sustainable thermal management concepts of urban groundwater bodies |
| VerfasserIn |
Matthias H. Mueller, Jannis Epting, Mandy Köhler, Falk Händel, Peter Huggenberger |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250105038
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| Publikation (Nr.) |
 EGU/EGU2015-4482.pdf |
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| Zusammenfassung |
| Increasing groundwater temperatures observed in many urban areas strongly interfere with
the demand of thermal groundwater use. The groundwater temperatures in these urban areas
are affected by numerous interacting factors: open and closed-loop geothermal systems for
heating and cooling, sealed surfaces, constructions in the subsurface (infrastructure and
buildings), artificial groundwater recharge, and interaction with rivers. On the one hand, these
increasing groundwater temperatures will negatively affect the potential for its
use in the future e.g. for cooling purposes. On the other hand, elevated subsurface
temperatures can be considered as an energy source for shallow geothermal heating
systems. Integrated thermal management concepts are therefore needed to coordinate
the thermal use of groundwater in urban areas. These concepts should be based
on knowledge of the driving processes which influence the thermal regime of the
aquifer.
We are currently investigating the processes influencing the groundwater temperature
throughout the urban area of Basel City, Switzerland. This involves a three-dimensional
numerical groundwater heat-transport model including geothermal use and interactions with
the unsaturated zone such as subsurface constructions reaching into the aquifer. The cantonal
groundwater monitoring system is an important part of the data base in our model, which will
help to develop sustainable management strategies. However, single temperature
measurements in conventional groundwater wells can be biased by vertical thermal
convection. Therefore, multilevel observation wells are used in the urban areas of the city to
monitor subsurface temperatures reaching from the unsaturated zone to the base of the
aquifer. These multilevel wells are distributed in a pilot area in order to monitor the
subsurface temperatures in the vicinity of deep buildings and to quantify the influence of the
geothermal use of groundwater.
Based on time series of the conventional groundwater wells, the multilevel observation
wells and the different boundary conditions we characterize the groundwater temperature
regimes using a regional groundwater heat-transport model. In the urban area of Basel, mean
annual groundwater temperatures are significantly increasing with 0.05 K per year in
the period of 1994 to 2014, which is most likely due to anthropogenic influences.
Overall, mean annual groundwater temperatures of Basel are 3.0 |
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