The interview highlights the crucial role of mentors such as Prof. Włodzimierz Czernuszenko, Prof. Vladimir Nikora and Prof. Richard S.L. Lee in shaping his career. Serendipitous encounters and international collaborations have significantly influenced his scientific journey. His research in environmental hydrodynamics includes turbulent mass and energy transport, statistical methods in hydrology, and climate change impacts. As Chair of the IAHR Europe Division Leadership Team, Pawel aims to promote hydro-environmental engineering and research through initiatives such as organizing regional congresses. In terms of academic publishing, he advocates quality over quantity and emphasizes the importance of peer review. Pawel values interdisciplinary collaboration in addressing complex challenges in hydro-environmental engineering, emphasizing integrated approaches and solutions.

It is extremely hard to distinguish those moments but let me just mention a few circumstances influencing my further career very much. Among them the most important were the people, excellent scholars that I have happened to meet and collaborate with. Particularly crucial were those people that I met in the beginning of that journey. The first to mention is probably Prof. Włodzimierz Czernuszenko, the supervisor of my PhD thesis, my first mentor and later a real friend. He died in 2022 and we, as a hydraulics science community, managed to commemorate him with a special session during the last IAHR World Congress in Vienna. He taught me how to deal with scientific questions and he introduced me to the world of mathematical modeling of physical processes in rivers. Let me also mention two other scholars who influenced my early career. One was the known to all of us, Prof. Vladimir Nikora. In the early nineties of last century he was not that well-known in the western world but his knowledge and enthusiasm were factors that affected my own scientific path. We performed common investigations, publications that we worked on that time opened a lot of doors to both of us. The third scholar that I want to mention was Prof. Richard S.L. Lee who hosted me when I was a visiting scholar at State University of New York at Stony Brook, USA in 1991/1992. He introduced me to a different world. It was a time when I was fascinated in two-phase flows and Richard was that time definitely one of the best experts in that field all over the world. And this was probably a milestone in my career. Today mobility is the bread and butter but please remember that it was a time when Poland just abolished communism and it was the very beginning of building democracy in Poland. Imagine that the fellowship program sponsored by Soros allowed only six Poles to go abroad (out of every scientific discipline). Such  competition is unimaginable nowadays.  So I was very lucky to go to USA and it totally changed my understanding of science. Soon after, in 1994, I received a very prestigious fellowship of the Foundation for Polish Science (it was the first edition of that program) and probably those two fellowships allowed me to stay in science. Let me also mention another factor at the very beginning of my scientific journey. I was a student of mathematics and I did not even think about dealing with rivers. My world then was related to differential equations and functional analysis. But it so happened that my supervisor at the University of Warsaw (Prof. Andrzej Palczewski) was brave enough to offer me to build a mathematical model of the spread of warm water released from a nuclear power station that was at that time under construction in Poland. It was the subject of my Master Thesis. A funny thing is that they never finished that investment but I did learn a lot and it directed me towards environmental hydraulics.  So you can see, there were a lot of coincidences in my early career. Later all key moments were somehow related to the people I met. I was lucky to cooperate with many fantastic individuals from many research centers all over the world. 

Indeed, there were various subject areas that I was involved in. I think majority of my work was somehow related to understanding of physical processes in rivers but there were various phases of my fascinations. As I mentioned earlier I studied mathematics which is very far from experimental studies but soon after I had started to deal with rivers I also was deeply involved in experimental investigations, both in rivers and laboratories. There was no other choice if you wanted to study and understand e.g. turbulence structure in open channels. But I was also exposed to the questions related to other time and space scales. It led me to e.g. questions of climate change impact on water resources and I had this privilege to work on the subject when it was not as obvious as today. I worked on developing a model that turned out to be used in many countries (various versions of climate-runoff CLIRUN model) in the late nineties and this I owned to yet another fantastic scholar, Prof. Zdzisław Kaczmarek.  I believe it is a right path to try to understand water at various scales – starting from turbulent processes in open channels towards catchment scales. It allows to have a broader view on the very hot topic of understanding of various processes in hydrosphere. 

Please remember that the Leadership Team is a cohort of fantastic scholars deeply involved in their research activities, devoting only some free time to IAHR. One of the key tasks of the division is to organize European regional congresses. I happened to co-chair one of them so I fully realize how difficult task is to design a good conference of that kind. But my ambition is also to motivate the LT to work on a common project and to  air our views on the most important issues related to water for our continent. Therefore we decided to organize a special session during the nearest IAHR Europe Congress in Lisbon on Disaster Risk Management in European Rivers and Coastal Areas. We also work on a special issue of one of IAHR journals on the same subject. And yet another crucial task for us is to attract more European researchers to IAHR. There are still European countries that do not have members in IAHR, there are also regions very much underrepresented in IAHR even if they are very strong in water sector. We need to gain more visibility as IAHR and it is one of key tasks of our LT.

This is indeed the question that should be elaborated extensively. We live in times when numbers, citations, how soon you can publish - count most. Current approaches rely on journal-based metrics. Researchers count their publications which is often counterproductive especially for young scientists. This unhealthy publish or perish culture has, in my opinion, negative effects on the quality of scholarly output. We need to reverse the process and pay particular attention to the quality of publications. It requires some shift in many related areas, like the way of assessment of achievements of researchers. The transition to research assessment practices that are based on qualitative peer review seems to be a must. 

Note that on the market there are more and more journals, unfortunately many of them are very poor in quality. Almost every day we all receive numerous invitations to submit papers, to arrange special issues etc. It all causes that is hard to find good reviewers of the journal papers. This is a matter of science culture and Earth, engineering and environmental sciences are not free from all those problems. We also face another trend which is open science. It will in the nearest future reshape the landscape of academic publishing. With the number of publications shared via the Gold Open Access model on the rise access to the results  of research is at an all-time high. But we need to remember that breaking down these barriers for readers has come at the expense of increased barriers for authors. The article processing charges are very high which introduces another sort of inequality in science. 

You mentioned one of my activities as the Editor in chief of monographic series. This is a very challenging task as well.  I have to honestly admit that it starts to be extremely difficult to attract scientists to write monographs and the reason is that “books do not count for advancement of their research careers” It is ridiculous. We very often seek good monographs. The scientific information  is dispersed over so many sources that it is hard to wise up in this total chaos.

You have rightly noticed that water related problems are extremely good examples of research requiring interdisciplinary approaches. We definitely observe interconnection of issues related to the motion of water with bio/eco component and therefore many subdisciplines like ecohydraulics appear as emerging scientific disciplines driving a lot from many other research areas. Let’s take as an example  various kinds of nature based solutions and - such solutions must be searched for with the engagement of society and stakeholders. And it imposes interdisciplinarity. Ecological status of freshwater ecosystems is determined by hydrological cycle, biological structure of the catchment, human activities and human impact, all of them are  determinants of ecological status. Integration of hydroengineering and the integrative science eco-hydrology allows for development of innovative solutions towards solving global, regional, and local water problems. Integrated knowledge in the field of ecology and hydrology, aligned with hydroengineering solutions, is enhancing the potential for sustainable development in a given catchment area. This involves the concept popularized in ecohydrology as WBSRC - a strategy, comprising water (W), biodiversity (B), ecosystem services (S), resilience to anthropogenic stress and climate change (R), climate and education (C), education (E). It has been broadly discussed during the last IAHR World Congress. It illustrates how interdisciplinary is the research area that we deal with. Hydraulics and particularly its environmental part  is booming and allows to tackle many research and practical problems of interdisciplinary character. As shown above a few research domains attract particular attention of scientific community. There are ongoing research and implementation studies on water quality and transport processes but the inquiry-driven studies focus mostly on complex morphological settings and vegetated channels. Indeed still many unanswered questions refer to flow- biota interactions.

And there is one more keyword that you used in your question. This is complexity. In principle scientists face the double, incredibly intricate problem of unraveling the cause and effect relationships between various phenomena and processes on one hand, and developing mathematical/computer language descriptions of the extraordinarily complicated reality on the other. This is the reality of water related science. And here involvement of interdisciplinary approaches is particularly challenging.

This question requires some elaboration. First we need to explain our readers what ALLEA is. It is the European Federation of Academies of Sciences and Humanities, representing more than 50 academies from about 40 EU and non-EU countries. It is extremely important – it covers all European territory, not just European Union which resembles IAHR Europe Division. Since its foundation in 1994, ALLEA speaks out on behalf of its members on the European and international stages, promotes science as a global public good, and facilitates scientific collaboration across borders and disciplines. Here I should explain that I am a member of Polish Academy of Sciences– this is  a life Membership in the PAS and is considered a great honor and an expression of the highest recognition for preeminent scholarly accomplishments. I happened to serve the Academy as its Vice President for 8 years and during that service I was elected a member of Board of ALLEA for which I have served 3 terms in the office (which will last until May this year).  Note that academies are self-governing bodies of distinguished scientists drawn from all fields of scholarly inquiry. They contain a unique human resource of intellectual excellence, experience and multidisciplinary knowledge dedicated to the advancement of science and scholarship in Europe and the world. I believe that ALLEA faces many important and challenging tasks; its advice is crucial for the geopolitical situation of science, for academic freedom, for a green transition in times of war, and the negotiations for the next EU frame program. The role of ALLEA and all science academies is particularly important at a time when populism and nationalism are growing in strength in many places in the world, and disinformation is everywhere. European Academies should speak a strong voice, bring science and its findings closer to the public, provide it with reliable information, and speak out on the most important issues. ALLEA should be also a voice of European science on a global level. ALLEA already is known for providing guidance on how to prevent research misconduct and enable researchers to follow best practice, particularly through the European Code of Conduct for Research Integrity. ALLEA shapes European research policy, especially the ERA and EU research framework programmes, and promote diverse mechanisms for the broad dissemination of and access to research through open science. Note that ALLEA speak on behalf of much more than 10,000 top scholars in more than 50 academies of 40 countries, and therefore has a legitimate and relevant voice in international research and research policy. As you can see I am deeply involved in activities of ALLEA and I see many possibilities for organizations like IAHR and ALLEA to cooperate. Both organizations deliberate and formulate sound scientific positions on fundamental issues related to science policy and societally relevant topics like climate or water crisis. 

I will try to touch upon a few aspects in a nutshell. Undoubtedly, the world is not on track to meet global targets related to water as defined for example in United Nations sustainable development goals. Water crises across the globe threaten the achievement of key development and environmental goals, given the significance of water in social, political and economic affairs across all scales. Some claim water is the oil in the 21st century.  And I do agree with such comparison. This is particularly valid in the face of rapid climate changes. Science and engineering solutions (and herein IAHR should spring into action) are indispensable for generating knowledge to address the complex interplay of natural and human factors that still hinder progress in resolving current water  challenges. This requires a more systematic dialogue between policy-makers and scientists on evidence-based policy options to support tangible action and anticipate future water-related risks. And again I believe IAHR should be more visible in that dialogue. 

In answering your question, going into the details,  let me focus on what we often call environmental hydraulics or more broadly environmental fluid mechanics.  Earth, water, and air make up the environmental continuum that surround living things. These three components of the environment influence one another in a dynamic way. This means that the environment should be seen as an integrated system, and this is precisely how it is treated in environmental hydrodynamics. This discipline is often seen as being limited to studying the processes of mass and heat transfer in the aquatic environment, taking into account the geometric complexity of the object being studied (for example plants). Here, we must use our knowledge about the physics of transport phenomena as well as the nature of chemical and biological transformations. The relevant tools are provided by classical hydrodynamics, typically used to describe technological structures. However, the quintessence of research in environmental hydrodynamics lies in recognizing the vast differences between environmental flows and their engineering counterparts. In technical contexts, it’s hard to imagine a man-made object with a structure as complex as a wild river flowing in many channels whose banks are covered by diverse plants and whose geometry changes over time. We try to capture and describe such differences. Attempts to understand the processes that are taking place for example in rivers and to describe them using the language of mathematics (which is what I mainly do) have a centuries-long history. However, we have never had to study the complexity of such processes in such great detail. Today, we know that rivers are very important ecological corridors characterized by abundant wildlife. We are likewise aware of growing threats caused by the human transformation of river channels. We are moreover facing new conditions caused by population growth and climate change as well as the necessity of managing water resources in keeping with the principles of sustainable development.

The main challenge and difficulty facing researchers  is the fact that the flow of water in rivers is always turbulent, and turbulence still remains one of the least understood phenomena. Water in rivers is subject to chaotic swirling motions even though the overall bulk of water flows in a specific direction. This is turbulence, which occurs when the velocity of the flow exceeds the value above which the viscous forces in water can no longer attenuate the chaotic motions of water molecules. This phenomenon is extremely complex, as is the geometry of every river, which further complicates the process we describe, for example the transport of pollutants. 

And when mentioning pollutants we need to remember about the relatively new threat posed by plastics, microplastics and pharmaceuticals. The latter ones are designed to be effective in low concentrations in order to avoid having to introduce foreign substances in high doses into our bodies. That makes them particularly dangerous to people as well as flora and fauna. In most countries, the content of pharmaceuticals in water is tested sporadically, but recently all the hormones and antibiotics being tested for were found in concentrations above the limits of detection, which is very alarming. The question is: how do these substances get into rivers? The wastewater treatment methods currently in use are usually insufficient, and pharmaceuticals enter the environment supply together with wastewater from sewage treatment plants. 

And as yet another challenge that IAHR should have on agenda is the modern approach to hydraulic structures and new hydroengineering investments. As for water resources management, water infrastructure is usually developed for the purposes of inland navigation, water and heat energy, water supply, water retention, and flood control. We must also not forget about tourism and recreation. The trick lies in finding a smart combination of these two roles of rivers – in ecosystems and in water management. This is the main challenge for science and for the people responsible for water resource management.

It is indeed most challenging for me to balance all mentioned activities and I do understand the saying that time is the most precious asset that we can have. I believe one of the most important skill is to be able to delegate the tasks and to be surrounded by collaborators that you trust. I believe I am a lucky devil and I do work with many fantastic individuals. When you ask about leadership I believe we should feel the difference between leading and managing. The leadership is about influencing people to follow, is about creating positive changes. And I believe I happened to have some of those skills. To me managing is just maintain systems and  processes. So leadership requires something more and when I look back I managed to lead various institutions through important changes. It concerned particularly the Institute of Geophysics of the Polish academy of Sciences that I am the head of at the moment (and was also in the past) and also Polish Academy of Sciences that I was the Vice President of over two terms in office. But I do have problems with talking about it. Once Margaret Thatcher said that being in power is like being a lady. If you have to tell people you are, you aren’t. I like this saying. You cannot claim yourself you are a leader. 

But any way let me elaborate on it a bit more. Leadership comes from your experience but also from your intuition. Every past success and failure you’ve experienced can be a valuable source of wisdom. But you need to allow it to be. You need to derive conclusions from past events, you need to learn from your mistakes. Leadership is also to some extent influencing intangibles such as morale or timing and this is intuition. And let me add that leaders must also be learners and that learning process is ongoing. And you need to build trust. When you ask about the teams that you work with, we need to remember that every organization requires diverse talents to succeed and one of key role of a leader is to express his/her appreciation for the skills that people have. 

Everything what I have mentioned is kind of my imagination of how to lead but how do I fulfill that picture can be assessed only by people that I work with.

We must be able to integrate the role of our field of studies into the new reality, characterized by the presence of knowledge-based societies, the provision of education in the digital sphere, and learning throughout life. We are now witnessing a fourth industrial revolution, involving such processes as the growing use of cyber-physical systems, the Internet of Things, and cloud computing, which will undoubtedly gain momentum in the coming years. And they will undoubtedly influence water sector very much.  The future world may be indeed very different from what we have become accustomed to. Our research community must respond to the challenges posed by changes that result from the climate crisis, demographic problems, migrations, and the rapidly changing labor market. 

These are very general remarks but related to what you have asked about very much. One of the changes that we face are related to all those cutting-edge technologies. The most effective use of generative AI will be in augmenting human creativity and obviously it concerns hydro-science as well. AI offers our research domain opportunity to improve decision-making processes and overall efficiency. Although most of my personal research has been devoted to physically-based models I happened to also work on, among others Swarm Intelligence and Evolutionary Algorithms, a few types of Genetic Algorithms  and the basic variants of Biogeography-Based optimization, Differential Evolution and Particle Swarm Optimization. Long time ago I started to use Multi-Layer Perceptron Neural Networks to obtain model parameters when I dealt with river transport processes and flood routing procedures. So I did have some hands on experience with the mentioned techniques. And I do believe it is a great future for all those techniques. They are already extremely useful in  various predictions, identification and control problems, also in fault diagnosis. In recent years machine learning algorithms have been increasingly used in environmental sciences due to their high capability for modelling non-linear phenomena. In particular, these algorithms are already widely used in e.g. flood forecasts, as well as in the analyses and modelling of hydrological and ecological data. They are also very useful in situations when we have large information gaps. I believe monitoring systems of the future will to large extent be based on the technologies you’ve mentioned.

I still hope that the achievements that I will be most proud of are still ahead of me. On the other hand side - longer you work, more you can find in your activities that might be of interest to others. I believe that my main contributions come from my studies on flow structure, including turbulence structure in rivers with complex geometry and in the presence of vegetation. I always worked kind of parallelly performing and assessing the results of experimental studies in laboratories but also in actual rivers. I also did some theoretical work and computational experiments. I am kind of proud of many studies on mathematical models of heat, oxygen and pollutant transport in rivers, analysing the mixing processes of pollutants in rivers and the impact of water-air exchange. Some of the outcomes are  practical decision-making tools for water protection in case of accidents, toxic inflows and environmental disasters. Together with various groups of researchers we performed unique tracer studies, which involve simulating an accident by releasing a safe dye into a river and observing what happens to this substance, where it gets deposited, and how long it stays in the river. The results teach us how to better respond to actual environmental disasters, when toxic substances may get introduced into water. But first of all they provide an immense material to study the fundamentals of transport processes in rivers. When I said unique studies, this is because of large space scales and complexity of the chosen rivers for our investigations (multithread river systems). I should also add numerous studies on unsteady flow conditions which resulted in original methods of evaluation of bed shear stresses in open channels. I believe I also contributed to the field with studies on modeling of solid particles transport in turbulent open channel flows and in experimental studies of sediment transport. In this interview I also mentioned my involvement in building a model allowing for the studies of climate change impact on water resources which is also important part of my scientific experience.

I need also to mention other achievements which are on organizational side. Quite recently I’ve co-organized two important symposia – one was the 6th IAHR Europe Congress titled Hydro-environment Research and Engineering - No Frames, No Borders that took place in 2021 in Warsaw and another one was the European Climate Conference in 2023 in Warsaw. Since 2006 I have organized (now together with my younger colleague, Monika Kalinowska) a series of International Schools of Hydraulics under the umbrella of IAHR. From 2020 I have co-organized the annual World Water Day celebrations in Poland under the patronage of UNESCO. I believe I should also mention contributions as the director of the Institute of Geophysics of the Polish Academy of Sciences. It was then when I initiated the foundation of the Center of Earth and Planetary Research GeoPlanet which in turn caused the creation of a book series published by Springer: Geoplanet: Earth and Planetary Sciences, which has so far produced more than 40 titles many of them come from hydroscience. Another thing that I believe brings credit to me is my involvement in establishing the Centre for Polar Studies (CPS) in Poland which is the joint international programme of leading Polish research units. In 2014 it won very prestigious competition Leading National Research Centre 2014-2018. The Centre focuses on better understanding of interaction between atmosphere, ocean and cryosphere by gathering and interpreting extensive data on processes taking place in the Arctic, so it is very much connected to our research community, as well. 

Source: https://www.iahr.org/index/detail/1322