GC_2-2013_KB.indd  Geologia Croatica 66/2 153–154 1 Fig. Zagreb 2013 Geologia CroaticaGeologia Croatica A response to the comment of Roller-Lutz et al. on the paper by Lukač Reberski et al. published in Geologia Croatica 66/1, 39–53 (2013): "Defi nition of the river Gacka springs subcatchment areas on the basis of hydrogeological parameters"  Jasmina Lukač Reberski1, Tamara Marković1 and Zoran Nakić2 1 Croatian Geological Survey, Sachsova 2, Zagreb, Croatia 2 University of Zagreb, Faculty of Mining, Geology and Petroleum Engineering, Pierottieva 6, 10 000 Zagreb, Croatia doi: 10.4154/gc.2013.13 As the authors of the above-mentioned paper in Geologia Croatica, issue 66/1, we felt the need to respond to the Com- ment made by Zvjezdana Roller-Lutz, Tamara Hunjak and Hans O. Lutz. We would like to refer to the claims: A) that we took isotope data (D and 18O) of springs for the year 2008 with- out consent, B) that isotope results were preliminary and shown only in an unpublished and not citable report, and C) that LMWL on fi g. 7 is plotted incorrectly. Ad A): In the paper Lukač Reberski et al. (2013), iso- topic data are presented for the period from 2002 till 2008. The isotope analyses of spring waters from 2002 till 2006 are the result of investigations carried out for the master the- sis of Jasmina Lukač Reberski (2008) which was a part of the project “Basic hydrogeological map of the Republic of Croatia 1:100 000” funded by the Croatian Ministry of Sci- ence, Education and Sports (Project number 181-1811096- 3165), and CRO/8/006 project funded by IAEA-TC (Inter- national Atomic Energy Agency – Technical Cooperation) coordinated by the Ruđer Bošković Institute (report is avail- able at: http://bib.irb.hr/prikazi-rad?&rad=312123). The iso- tope analyses of spring waters for the year 2008 are the result of a cooperation project IAEA-TC CRO/8/007 coordinated by the University of Rijeka, Faculty of Medicine, in which the Croatian Geological Survey (CGS) also participated in a manner that researchers of the CGS performed fi eld work (water sampling, discharge measurements and measurements of in situ physico-chemical parameters). They also measured water chemical parameters in their laboratory. Based on the verbal agreement between researchers of the project CRO/8/007, the preliminary isotope data of spring waters (only for the year 2008) were given to researchers from the CGS, for the purpose of writing the PhD thesis (Lukač Re- berski, 2011). Since PhD theses are available to the public, any data contained therein cannot be considered confi dential. Ad B): The aim of the paper by Lukač Reberski et al. (2013) was to present the overview of the PhD thesis (Lukač Reberski, 2011) and new insights about the river Gacka springs catchment area. Furthermore, the University of Ri- jeka asked the researchers from the CGS to cite the published paper (Mandić et al., 2008) where the preliminary data were analysed. The mentioned paper was cited in the PhD thesis (Lukač Reberski, 2011) and also in the paper: Lukač Reber- ski et al. (2013). That is the reason why the stable isotope data were included in the paper, although it had minor infl u- ence to the conclusions. Ad C) An unintentional error occurred in Figure 7 dur- ing the diagram construction due to which the graphical line that represents LMWL slightly moved from its original po- sition. Here is corrected fi gure 7. However, the explanation for Figure 7 is cited from the paper Mandić et al., 2008. Geologia Croatica 66/2Geologia Croatica 154 REFERENCES HORVATINČIĆ, N., ROLLER-LUTZ, Z., KAPELJ, S. (2007): Applica- tion of isotope techniques in investigation of water resources and water protection in the Karst area of Croatia (IAEA TC CRO/8/006) (fi nal report). LUKAČ REBERSKI, J, MARKOVIĆ, T., NAKIĆ, Z. (2013) Defi nition of the river Gacka springs subcatchment areas on the basis of hy- drogeological parameters.– Geologica Croatica, 66/1, 39-53. LUKAČ REBERSKI, J. (2011) Određivanje podsljevova izvorišta rijeke Gacke na osnovi hidrogeoloških parametara [Defi nition of the riv- er Gacka springs subcatchment areas on the basis of hydrogeologi- cal parametars – in Croatian].– Doctoral Thesis. Rudarsko geološko naftni fakultet, Sveučilište u Zagrebu (Faculty of Mining, Geology and Petroleum Engineering, University of Zagreb), 158 p. LUKAČ REBERSKI, J. (2008): Hidrogeološka i hidrogeokemijska os- nova za defi niranje slijeva Gacke i zaštita njenog izvorišta [Hydro- geological and hydrogeochemical basis for the catchment area defi nition: Gacka river springs catchment area – in Croatian].– Master’s Thesis. Rudarsko-geološko-naftni fakultet, Sveučilište u Zagrebu (Faculty of Mining, Geology and Petroleum Engineer- ing, University of Zagreb), 118 p. MANDIĆ, M., BOJIĆ, D., ROLLER-LUTZ, Z., LUTZ, H. & BRONIĆ KRAJCAR, I. (2008): Note on the spring region of Gacka River (Croatia).– Isotop. Envir. Health Studies, 44/2, 201–208. doi: 10.1080/10256010802066364. Available online April 19, 2013 Figure 7: The ratio of oxygen -18 and deuterium stable isotopes in spring waters of the Gacka catchment.