Research “Hylight”: Hydrological response characteristics of Mediterranean catchments at different time scales: a meta-analysis by Merheb et al.


Mohammad Merheb

In January 2016, Mohammad Merheb and colleagues published a paper on comparative Mediterranean hydrology in Hydrological Sciences Journal. At the 2017 IAHS General Assembly, Mohammad was awarded the Tison award for this paper, and we decided to ask him a couple of questions.

Q: Let’s start with the basics. Where are you from, where are you based, and what are you working on now?

A: I am from a small village called El-Bireh located in Akkar district in the northern part of Lebanon. Now, I live and work in Tripoli, a port city in northern Lebanon where I am based at the Lebanese University. However, I must say that the article that won the Tison award was written when I was doing my PhD. I was based in Irstea, Montpellier, France and the L-CNRS, Beirut, Lebanon.

Nowadays, my main work is teaching. Nevertheless, I am still working on some research projects that I have started during my PhD. These are mostly related to catchment classification and regionalization studies.

Q: What is the main message of your paper?

A: The main message of my paper is that it is not always enough to take a model from the literature and run it on your catchment with your data and get a high NS coefficient. This might be useful for water resources management studies but it will not permit us to really understand the underlying hydrological processes of the catchment, especially when one is working on very heterogeneous region such as the Mediterranean. There should be more focus on taking into account the particularities of each climatic region. One should try and develop new “tailor-made“ or data-driven models that best fit the region of interest, or at least adapt existing models to the specific conditions of the area in question.

Q: With this paper you won the IAHS Tison award for young hydrologists. How did that process go?

A: After my paper got accepted in HSJ, it was chosen as a feature article. When an article is chosen as a feature article and if at least one the co-authors is under 41 of age, the article will be nominated for the Tison award. That’s what happened. And finally, when the article won the award, we received the good news via an email from the IAHS Secretary General Christoph Cudennec.

Q: For your paper you did a meta-analysis of 140 hydrological studies. Do you think meta-analyses are the way forward to really get a better understanding of hydrological processes, or are single-catchment studies also still useful?

Single-catchment studies are hugely important. We cannot advance our knowledge on the hydrological processes without such studies, and it not possible to do a meta-analysis without access to large number of single-catchment studies. Nevertheless, we also need meta-analyses or reviews that bring together all this fragmented knowledge acquired from numerous single catchment studies. So they are both equally important.

Q: Your paper focuses on Mediterranean catchments. What is so interesting or special about Mediterranean hydrology?

A: Mediterranean catchments are special in that they are neither humid nor arid, they are in between. So, they exhibit a huge heterogeneity in their response. Sometimes they act like humid catchments, some other times like arid ones. Even, in the same catchment and in a single event, you may find that runoff generation processes are not homogeneous due to the high spatial and temporal variability of rainfall. Furthermore, due to the topography of the region, these are mostly small to medium sized catchments which mean their response time can be very short, thus they are prone to flash floods. Finally, these catchments exhibit a long summer drought; they can go up to 4 months without receiving any precipitation. Hence, you can think about the Mediterranean hydrology as the hydrology of extremes, oscillating between high intensity short duration rainfall events and long dry periods.

Q: What is the next prize you hope to win?

A: Well, I don’t really focus on that. I wasn’t expecting to win the Tison Award and I don’t expect to win any other prize. I certainly hope that I will continue to produce good research even if it is not that easy in a developing country such as Lebanon. And if my future works earn me any other prize that will be great!

2017 IAHS Tison Award Winner Mohamammad Merheb with Demetris Koutsoyiannis (HSJ Editor) and Christoph Cudennec (IAHS Secretary General) at the IAHS Scientific Assembly 2017 in Port Elizabeth, South Africa

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