Prof. Dr. Ralf Merz

Head of Department
Department Catchment Hydrology

Helmholtz-Centre for
Environmental Research - UFZ
Theodor-Lieser-Str. 4
06120 Halle (Saale), Germany

Tel: +49 (0)341 6025 4199

Persönliche Bild

Short CV

Ralf Merz is head of the Department of Catchment Hydrology of the Helmholtz Centre for Environmental Research and Full Professor of Catchment Hydrology at the Martin-Luther University Halle-Wittenberg since 2011. He received his MSc of Civil Engineering at the Technical University of Karlsruhe in 1997 and his PhD at the Vienna University of Technology in 2002. His international experience includes a research position at Vienna University of Technology and at the University of Lancaster, UK. In 2006 he has received the renowned APART research grant of the Austrian Academy of Sciences. In 2009 he took his Habilitation in Hydrology at the Vienna University of Technology. He is or has been involved in numerous research and consulting projects at the national and international level.

Research interests

  • Catchment Modelling
  • Comparative Hydrology
  • Regional monitoring and process analysis
  • Hydrology of (semi) arid regions
  • Flood risk assessment and flood estimation


You could use our publication index for further requests.

2024 (1)

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2023 (9)

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2022 (7)

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2021 (3)

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2020 (5)

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2019 (2)

  • Blöschl, G., Hall, J., Viglione, A., Perdigão, R.A.P., Parajka, J., Merz, B., Lun, D., Arheimer, B., Aronica, G.T., Bilibashi, A., Boháč, M., Bonacci, O., Borga, M., Čanjevac, I., Castellarin, A., Chirico, G.B., Claps, P., Frolova, N., Ganora, D., Gorbachova, L., Gül, A., Hannaford, J., Harrigan, S., Kireeva, M., Kiss, A., Kjeldsen, T.R., Kohnová, S., Koskela, J.J., Ledvinka, O., Macdonald, N., Mavrova-Guirguinova, M., Mediero, L., Merz, R., Molnar, P., Montanari, A., Murphy, C., Osuch, M., Ovcharuk, V., Radevski, I., Salinas, J.L., Sauquet, E., Šraj, M., Szolgay, J., Volpi, E., Wilson, D., Zaimi, K., Živković, N. (2019):
    Changing climate both increases and decreases European river floods
    Nature 573 (7772), 108 - 111 10.1038/s41586-019-1495-6
  • Tarasova, L., Merz, R., Kiss, A., Basso, S., Blöschl, G., Merz, B., Viglione, A., Plötner, S., Guse, B., Schumann, A., Fischer, S., Ahrens, B., Anwar, F., Bárdossy, A., Bühler, P., Haberlandt, U., Kreibich, H., Krug, A., Lun, D., Müller‐Thomy, H., Pidoto, R., Primo, C., Seidel, J., Vorogushyn, S., Wietzke, L. (2019):
    Causative classification of river flood events
    Wiley Interdiscip. Rev.-Water 6 (4), e1353 10.1002/wat2.1353
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2018 (6)

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2017 (6)

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2016 (7)

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2015 (6)

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2014 (8)

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2013 (6)

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2012 (7)

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2011 (10)

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2010 (1)

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Publications (selected)

Rödiger, T., Siebert, Ch., Krause, P., Geyer, St., Mallast, U., Merz, R. (2013) Multi-response calibration of a conceptual hydrological model in the semiarid catchment of Wadial Arab, Jordan, accepted for J. Hydrol.

Meier, Ch., Knoche, M., Merz, R., Weise, St. (2013) Stable isotopes in river waters in the Tajik Pamirs: regional and temporal characteristics, Isotopes in Environmental & Health Studies, in press.


Mallast, U., Siebert, C., Wagner, B., Sauter, M., Gloaguen, R., Geyer, S., Merz, R. (2013) Localisation of groundwater inflow and temporal discharge variability along the Dead Sea using thermal satellite data, Environ Earth Sci 69:587–603, DOI 10.1007/s12665-013-2371-6

Schulz, St., Siebert, Ch., Rödiger, T., Al-Raggad, M., Merz, R. (2013) Application of the water balance model J2000 to estimate groundwater recharge in a semiarid environment – a case study in the Zarqa River catchment, NW-Jordan, Environ Earth Sci 69:605–615, DOI 10.1007/s12665-013-2342-y

McIntyre, N., Ballard, C., Bruen, M., Bulygina, N., Buytaert, W., Cluckie, I., Dunn, S., Ehret, U., Ewen, J., Gelfan, A., Hess, T., Hughes, D., Jackson, B., Kjeldsen, T., Merz, R., Park, J-S., O'Connell, E., O'Donnell, G., Oudin, L., Todini, E., Wagener T. and Wheater, H. (2013) Modelling the hydrological impacts of rural land use change, Hydrolgy Research, in press, doi:10.2166/nh.2013.145.

Viglione, A., Merz, R., Salinas, J. & Blöschl, G. (2013) Flood Frequency Hydrology: 3. Bayesian framework, Water Resour. Res., 49, 1–18, DOI:10.1029/2011WR010782



Brigode, P. Bernardara, P. Gailhard, J., Gravaglia, F. Ribstein, P. & Merz, R. (2012) Optimization of the geopotential heights information used in a rainfall based weather patterns classification over Austria, Intern. Journal of Climatology, DOI:10.1002/joc.3535

M. Rogger, B. Kohl, H. Pirkl, A. Viglione, J. Komma, R. Kirnbauer, R. Merz and G. Blöschl (2012) Runoff models and flood frequency statistics for design flood estimation in Austria - do they tell a consistent story?, J. Hydrol., 10.1016/j.jhydrol.2012.05.068

Rogger, M., Pirkl, H. Viglione, A., Komma, J., Kirnbauer, R., Merz, R. & Blöschl, G. (2012) Step changes in the flood frequency curve – process controls, Water Resour. Res., 48, W05544, doi:10.1029/2011WR011187

Gaal, L., Szolgay, J., Kohnova, S., Parajka, J., Merz, R., Viglione, A., Blöschl, G. (2012) Flood time scales – understanding the interplay of climate and catchment processes through comparative hydrology, Water Resour. Res., 48, W04511, doi:10.1029/2011WR011509,

Viglione, A., Castellarin, A. Rogger, M., Merz, R., & Blöschl, G. (2012) Extreme rainstorms: testing regional envelope curves against stochastically generated events, Water Resour. Res., 48, W01509, doi: 10.1029/2011WR010515.


Blöschl, G., Schöner, W., Kroiß, H., Blaschke, A.P., Böhm. R., Haslinger, K., Kreuzinger, N., Merz, R., Parajka, J., Salinas, J.L., Viglione, A. (2011) Anapssungsstrategien an den Klimawandel für Österreichs Wasserwirtschaft – Ziele und Schlussfolgerungen der Studie für Bund und Länder, Österreichische Wasser- und Abfallwirtschaft, (1-2/2011), 1-11.

Blöschl, G., Viglione, A., Merz, R., Parajka, J. Salinas, J.L., Schöner, W. (2011) Auswirkungen des Klimawandels auf Hochwasser und Niederwasser, Österreichische Wasser- und Abfallwirtschaft, (1-2/2011), 11-21.

Blaschke, A.P., Merz, R., Parajka, J. Salinas, J.L., Blöschl, G. (2011) Auswirkungen des Klimawandels auf das Wasserdargebot von Grund- und Oberflächenwasser, Österreichische Wasser- und Abfallwirtschaft, (1-2/2011), 11-21.

Ley, R. Casper, M.C., Hellbrand, H. & Merz, R. (2011) Catchment Classification by Runoff Behaviour with Self-Organizing Maps (SOM), Hydrology and Earth Syst. Sci. (HESS), 15, 2947-2962, doi:10.5194/hess-15-2947-2011

Rogger, M., Viglione A., Merz, R., Kirnbauer, R., Pirkl, H. & Blöschl, G. (2011) Towards understanding the differences between deterministic and probabilistic flood hazard estimation methods, IAHS Publ. 347, 16-21

Merz, R., Parajka, J. & Blöschl, G. (2011) Time stability of catchment model parameters – implications for climate impact analyses, Water Resour. Res., 47, W02531, doi:10.1029/2010WR009505


Parajka J., Kohnova, S., Bálint G., Barbuc M., Borga M., Claps P., Cheval S., Dumitrescu A. Gaume E., Hlavčová K., Merz R., Pfaundler M.,  Stancalie G.,  Szolgay J., Blöschl G. (2010) Seasonal characteristics of flood regimes across the Alpine–Carpathian range Journal of Hydrology, 394, doi:10.1016/j.jhydrol.2010.05.015


Castellarin, A., Merz, R. and Blöschl G. (2009) Probabilistic Envelope Curves for Extreme Rainfall Events; Journal of Hydrology, 378 (3-4) 263-271.

Merz, R., Parajka, J. & Blöschl, G. (2009) Scale effects in conceptual hydrological modelling, Water Resour. Res., 45, W09405, doi:10.1029/2009WR007872.

Norbiato, D., Borga, M., Merz, R., Blöschl, G., Carton, A. (2009) Controls on event runoff coefficients in the eastern Italian Alps, Journal of Hydrology 375, doi:10.1016/j.jhydrol.2009.06.044

Viglione, A., Merz, R. and Blöschl, G. (2009) On the role of the runoff coefficient in the mapping of rainfall to flood return periods, Hydrology and Earth Syst. Sci. (HESS), 13, 577-593.

Merz, R. (2009) Advances in regionalising flood probabilities. (Schumann, A. Hrsg.) “Flood risk assessment and management: How to specify hydrological loads, their consequences and uncertainties”, Springer Sciences, Dordrecht, pp 97-115 DOI: 10.1007/978-90-481-9917-4_6

Parajka, J., Kohnová, S., Merz, R., Szolgay, J., Hlavčová, K., Blöschl, G. (2009) Comparative Analysis of the Seasonality of hydrological characteristics in Slovakia and Austria, Hydrological Science Journal, 54(3),doi: 10.1623/hysj.54.3.456

Merz, R. and G. Blöschl (2009), A regional analysis of event runoff coefficients with respect to climate and catchment characteristics in Austria, Water Resour. Res., 45, W01405, doi:10.1029/2008WR007163.



Merz, R. & Blöschl, G. (2008) Process controls on the statistical flood moments – a data based analysis, Hydrological Processes, DOI: 10.1002/hyp.7168.

Parajka, J., Merz, R., Szolgay, J., Blöschl, G. Kohnova, S. & Hlavcova, K. (2008) A comparison of precipitation and runoff seasonality in Slovakia and Austria, Meterological Journal, 11, 9-14.

Merz, R. & Blöschl, G. (2008) Hochwasserabflüsse in Österreich - das HORA Projekt, Österreichische Wasser- und Abfallwirtschaft, 60(9/10), 129-138.

G. Blöschl & R. Merz (2008) Estimating flood risk in Austria, Slovak Journal of Civil Engineering 16(3), pp. 13-20.

Merz, R. & Blöschl, G. (2008) Flood Frequency Hydrology 1: Temporal, spatial and causal expansion of information, Water Resources Research, 44, W08432, doi:10.1029/2007WR006744.

Merz, R. & Blöschl, G.(2008) Flood Frequency Hydrology 2: Combining data evidence, Water Resources Research, 44, W08433, doi:10.1029/2007WR006745.

Blöschl, G. & Merz, R. (2008) Bestimmung von Bemessungshochwässern gegebener Überschreitungswahrscheinlichkeit – Aspekte einer zeitgemäßen Strategie (Estimating Design Floods of a Given Return Period - Facets of a Contemporary Strategy),Wasserwirtschaft, 98(11), 12-18.

Merz, R. & Blöschl, G. (2008) Informationserweiterung zur Bestimmung von Hochwasserwahrscheinlichkeiten (Extended information basis for the determination of flood probabilities), Hydrologie und Wasserbewirtschaftung, 52(6), 300-309.

Merz, R., Blöschl, G. & Humer, G. (2008) National flood discharge mapping in Austria. Natural Hazards, doi:10.1007/s11069-007-9181-7.


Parajka, J. Blöschl, G., Merz, R. (2007) Regional calibration of catchment models – potential for ungaughed catchments, Water Resources Research, doi: 10.1029/2006WR005271.

Parajka, J., Merz, R. & Blöschl, G. (2007) Uncertainty and multiple objective calibration in regional water balance modelling. Hydrological Processes, doi: 10.1002/hyp.6253.


Merz, R., Blöschl, G. & Parajka, J. (2006) Spatio-temporal variability of event runoff coefficients. Journal of Hydrology, 331, 591-604, doi:10.1016/j.jhydrol.2006.06.008.

Parajka, J., Naeimi, V., Blöschl, G., Wagner, W., Merz, R. & Scipal, K. (2006) Assimilating scatterometer soil moisture data into conceptual hydrologic models at the regional scale. Hydrology and Earth System Sciences (HESS), 10, 353-368.

Merz, R., Blöschl G. & Parajka, J. (2006) Regionalisation methods in Rainfall-runoff modelling using large catchment samples, IAHS Publ. no. 307, S. 117-125.

Merz, R. & G. Blöschl (2006) Ereignisbezogene Abflussbeiwerte. Kartenblatt für Hydrologischer Atlas Österreich. Österreichischer Kunst und Kulturverlag und Bundesministerium für Land- und Forstwirtschaft, Umwelt und Wasserwirtschaft, Wien, Wien.

Skøien, J., Merz, R. & Blöschl, G. (2006) Top-Kriging - geostatistics on stream networks. Hydrology and Earth System Sciences (HESS), 10. 277-287.


Parajka, J., Merz, R. & Blöschl, G. (2005) A comparison of regionalisation methods for catchment model parameters. Hydrology and Earth System Sciences (HESS), 9, 157-171.

Sivapalan, M., Blöschl, G., Merz, R. & Gutknecht, D. (2005) Linking flood frequency to long-term water balance: incorporating effects of seasonality. Water Resources Research, 41, W0612, doi:10.1029/2004WR003439

Merz, R., Blöschl, G. & Parajka, J., (2005) Raum-zeitliche Variabilität von Ereignisabflussbeiwerten in Österreich. Hydrologie und Wasserbewirtschaftung, Heft 50(1),S. 2-11.

Parajka, J., Merz, R. & Blöschl, G. (2005) Regionale Wasserbilanzkomponenten für Österreich auf Tagesbasis. Österreichische Wasser- und Abfallwirtschaft, 57, Heft 3/4, 43-56.

Blöschl, G., Merz, R. & Reszler, Ch. (2005) Floods in Austria, Proceedings NATO Conference on extreme hydrological events in Novosibirsk, July 2005, NATO Science Series (78), Springer Verlag, doi. 10.1007/978-1-4020-5741-0_6

Merz, R. & Blöschl, G. (2005) Flood frequency regionalisation – spatial proximity vs. catchment attributes. Journal of Hydrology, 302, 283-306.


Merz, R. & Blöschl, G. (2004) Regionalisation of catchment model parameters. Journal of Hydrology, 287, 95-123.


Merz, R. & Blöschl G. (2003) Regional flood risk - what are the driving processes? In: G. Blöschl, S. Franks, M. Kumagai, K. Musiake, D. Rosbjerg (Eds.) Water Resources Systems - Hydrological Risk, Management and Development (Proc. Sapporo Symp. July 2003. IAHS Publ. no. 281, S. 49-58.

Merz, R. & G. Blöschl (2003) Saisonalität von Niederschlag und Abfluss. Karte 5.3, Hydrologischer Atlas Österreich. Österreichischer Kunst und Kulturverlag und Bundesministerium für Land- und Forstwirtschaft, Umwelt und Wasserwirtschaft, Wien.

Merz, R. & G. Blöschl (2003) Normierte mittlere Hochwasserspende. Karte 5.4, Hydrologischer Atlas Österreich. Österreichischer Kunst und Kulturverlag und Bundesministerium für Land- und Forstwirtschaft, Umwelt und Wasserwirtschaft, Wien.

Merz, R. & Blöschl, G. (2003) A process typology of regional floods. Water Resources Research, 39, 12; 1340 - 1359.