Identification of a karst system’s intrinsic hydro

Authors: Andreas Hartmann Martin Kralik Franko Humer Jens Lange Markus Weiler

Publish Date: 2011/03/31

Volume: 65, Issue: 8, Pages: 2377-2389

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Abstract

For water management purposes information about an entire aquifer system is generally more important than information about a specific spring Since a karstic aquifer system might drain to several outlets conclusions derived from a single spring can be misleading for characterization and modeling In this study we apply a conceptual model to an Alpine dolomite karst system in Austria The particular challenge was that several small springs with strongly varying hydrological behavior and diffuse flow into surrounding streams drain this system Instead of applying the model to a single spring it was calibrated simultaneously to several observations within the system aiming to identify the karst system’s intrinsic hydrodynamic parameters Parameter identification is supported by modeling the transport of water isotopes δ18O The parameters were transferred to the whole system with a simple upscaling procedure and a sensitivity analysis was performed to unfold influence of isotopic information on parameter sensitivity and simulation uncertainty The results show that it is possible to identify system intrinsic parameters But the sensitivity analysis revealed that some are hardly identifiable Only by considering uncertainty reasonable predictions can be provided for the whole system Including isotopic information increases the sensitivity of some intrinsic parameters but it goes along with a sensitivity decrease for others However a possible reduction of prediction uncertainty by isotopic information is compensated by deficiencies in the transport modeling routinesThanks to MariaTheresia Grabner Thomas Dirnböck Florian Wenter and Johannes Kobler from the Environment Agency Austria for providing their data and valuable advice to the measurement team Manuela Nied Nicole Jackisch Matthias Ritter Benjamin Gralher and Julien Farlin for their brave encouragement in taking samples and measuring runoff during the rainfallrunoff event to Irene Kohn and Jürgen Strub from the Institute of Hydrology for reviewing the paper and designing the figures and to Juraj Parajka from the Institut für Wasserbau und Ingenieurhydrologie Technische Universität Wien for providing information to calibrate the snow routine

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