EGU General Assembly 2020
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Modeling spatial and temporal hydrologic variability of karst vulnerability at a large Slovenian karst aquifer

Mirjam Scheller1, Matej Blatnik2, Blaž Kogovšek2, Yan Liu1, Cyril Mayaud2, Metka Petrič2, Nataša Ravbar2, and Andreas Hartmann1
Mirjam Scheller et al.
  • 1Chair of Hydrological Modeling and Water Resources, Freiburg University, Freiburg, 79098, Germany
  • 2Karst Research Institute ZRC SAZU, Postojna, 6230, Slovenia

About 50% of the Slovene drinking water demand are covered by karst aquifers. Consequently, appropriate protection and sustainable management of these aquifers are essential. Due to the hydrologic complexity and variability of karst systems, predicting potential contaminations and aquifers’ responses to changes in climate conditions, remains a challenge for karst research. In this study, the dynamics of potential solute contaminant transport in the Unica springs catchment, located in the southwest of Slovenia, are characterized and simulated with a semi-distributed karst model. The catchment encompasses autogenic and allogenic recharge across an area of about 820 km². The autogenic karst massive hosts one of Europe’s largest confluences of subterranean river branches and is strongly karstified. To take into account the temporal and spatial characteristics of the catchment, the model is linked with a GIS-based approach to assess spatiotemporal karst vulnerability. The validation of the model is performed by discharge observations and tracer experiments. The resulting simulations enable us to identify hot spots and hot moments of high contamination risks. By simulating solute contaminant transport during extremely dry and extremely wet years, we show that contaminant transport slows down under dry conditions. This can be explained by fast flow pathways not being activated or hydraulically connected under low flow conditions, which results in a retention and dilution of the contaminant in the aquifer. Our new approach improves the understanding of potential contaminants' transport behavior in a large complex karst system and justifies the consideration of spatiotemporal hydrologic variability in solute transport forecasting. It proposes a good basis for a better evaluation, management and protection of water resources in karst areas.

How to cite: Scheller, M., Blatnik, M., Kogovšek, B., Liu, Y., Mayaud, C., Petrič, M., Ravbar, N., and Hartmann, A.: Modeling spatial and temporal hydrologic variability of karst vulnerability at a large Slovenian karst aquifer, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-1009,, 2019

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