Hydrological Sciences

EGU Guest blogger

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Featured catchment series: The North will rise again!

Featured catchment series: The North will rise again!

This is the first post of “Featured Catchment”, a series of posts in the HS Blog that present experimental catchments across Europe and beyond. Here, the authors of the posts will explain the main characteristics (e.g., climate, geology, topography, land use) of their catchments, why hydrologic research is important in their study areas, describe the applied methodologies (field instrumentation and hydrological models), main findings and both current and future challenges.

The North will rise again! Ecohydrology at the subarctic Pallas research supersite

A unique insight to Arctic hydrology

A special character of the Pallas catchment comes from its northern location at 68°N, about 130 km north from the Arctic Circle in subarctic Finland. To our knowledge Pallas is the most northern research catchment not influenced by permafrost, which makes it a possible analog to permafrost catchments of the future once they lose their frozen soil base. Recent unprecedented rates of environmental change in the Arctic has alerted the scientific community, but at the same time the number of active high-latitude research catchments has been in persistent decline. To answer the call for hydrological research of the north, we started our ecohydrology work at the Pallas in 2014.

Site introduction aboard a drone; view of the snowy landscape with key hydrologically relevant numbers.

Northern Stable Isotope Monitoring program

Northern lights above the lodging facilities of Parks and Wildlife Finland keep the spirits high between days of cold field work.

We look at northern ecohydrology through a lens of a comprehensive northern stable water isotope monitoring program. Our mission is to get a detailed overview of the full Arctic water cycle, from oceans to rainfall and the subsequent partitioning between vegetation, groundwater and headwater streams, by using stable isotopes of water (2H, 18O).

Specifically, the Northern Stable Isotope Monitoring program at the Pallas catchments consists of:

  • continuous high-frequency in-situ stable water isotope monitoring of atmospheric water vapour and stream water (Academy of Finland funded postdoctoral scientist Hannah Bailey and by UArctic Chairship postdoctoral scientist Dr. Kaisa-Riita Mustonen)
  • extensive snow stable water isotope monitoring program to measure spatial and temporal variability in the isotopic composition of snowpack and snowmelt (PhD project of Kashif Noor)
  • soil water flux isotope measurements using lysimeters, soil coring, and experimental tracer approaches to characterize the water movement in the shallow subsurface (PhD project of Filip Muhic)
  • Water isotope sampling from plants to better understand the role of vegetation in the short growing season of the northern water cycle.

Hydrological collaborations with interdisciplinary environmental science

Example of a monitoring station on a peatland in the valley bottom.

Another special feature of the site is the interdisciplinary environmental research carried out by five Finnish national research institutes (FMI, LUKE, SYKE and GTK) in the Pallas region. Pallas comprises one of the most important climate and ecosystem research station in the circumpolar region. The extremely high-quality atmospheric water and greenhouse gas (GHG) measurements in the area (four Eddy-covariance flux stations within 10km2 and a high-precision atmospheric concentration measurement station both operated by FMI) compliments the hydrological research activities. Ongoing collaborative research projects aim to:

  • Investigate the influence of soil water condition in GHG exchange and carbon balance from boreal forest soils (FMI, Dr. Annalea Lohila)
  • Monitor carbon and GHG emission from headwater streams to study the influence of instream microbiology and hydrological connectivity of the stream and the landscape (University of Oulu, Dr. Jussi Jyväsjärvi)
  • Understand how hydrology and soil microbes are controlling soil GHG production potential in subarctic landscape (FMI, LUKE and University of Helsinki)
  • Monitor snow, vegetation and soil moisture by using drones (PhD project of Leo-Juhani Meriö, University of Eastern Finland and Dr. Timo Kumpula)
  • Determine the atmospheric fallout derived black carbon in snow and melting waters (Dr. Outi Meinander, FMI)

Ongoing work and current challenges

Unravelling the complex relationship of water and carbon in the North
Where can we find the hotspots for hydrology and biogeochemical activity? The usual suspects are the stream and its riparian zone, and groundwater exfiltration areas, such as springs and seepages. We hypothesize that better understanding of hydrological flow path activation in space and in time will help explain the carbon and nitrogen dynamics and GHG emissions from northern landscapes.

Conceptual idea of key processes and fluxes linking the water and carbon cycle in the Pallas study catchment.

Understanding our data through numerical modelling
Our long-term objective is to develop a numerical model to simulate the hydrological (aided by stable isotopes of water) and carbon cycle in the north. We argue that numerical modelling based on extensive and long-term biogeochemistry and hydrometric datasets is the best available tool for data integration across our collaborative disciplines in hydrology, ecology, and atmospheric sciences. For example, the PhD project of Anna Jaros is using integrated hydrological modelling to study the role of groundwater in sustaining peatland ecosystem.

Snow and ice – hydrological and practical challenges

We like to dig a bit deeper – working on pits to measure snow density and sample snow for water isotopes.

We need to keep up the struggle with the harsh cold northern environment. How do instruments survive and how do we get samples taken in the dead of the winter, when temperatures are below -35 °C and amount of daylight is minimal? Winter conditions prevail for more than half of the year, and we need to be able to monitor that half too to understand the system as a whole. We currently lack understanding of key processes during winter, such as hydrological and biogeochemical activity during winter below the snow and ice cover, influence of seasonal frost on hydrological partitioning of snowmelt, and isotope hydrology of snowpack and snowmelt.

Time lapse of spring 2018 snowmelt at stream gauging station. The highest flows in the catchment result from spring snowmelt, and we see how the peak flow occurs at very late stages of snowmelt. What happens in between the snowmelt initiation and the peak flow? Where is water stored, what parts of the catchment contribute to streamflow?

Got interested? Please get in touch to start a collaboration in exploring northern latitudes with Arctic attitudes! www.oulu.fi/water/pallas

Funded research projects:

– Pallas is a key site of Academy of Finland funded Arctic Interactions (ArcI Profi4) strategic research profile of the University of Oulu, led by Prof Björn Klöve
– High-resolution Arctic water isotope (δ18O & δ2H) cycles record and reveal sea ice-atmosphere-hydrologic (SIAH) interactions. Academy of Finland award, Jeffrey Welker.
– Pan-Arctic Precipitation Isotope Network (PAPIN), EU INTERACT award, led by Jeffrey Welker.
– What happens to snow when it melts? Academy of Finland Postdoctoral Researcher grant, Pertti Ala-aho.
– What is the role of other-than-peaty-soils for the catchment-scale methane balance and what are the hydrological linkages to CH4 production-oxidation processes. Academy of Finland project UPFORMET, PI Annalea Lohila
– Supersite for Arctic environmental research – a new study area for ​​Arctic hydrology, Maa- ja Vesitekniikan tuki ry, PI Hannu Marttila
– Surface-groundwater interaction in boreal peatland-esker systems: conceptualization of hydrogeological process, integrated numerical modelling and assessment of climate change. Kvantum institute, Strategic research project of the University of Oulu, PI Prof Bjørn Kløve
– Interactions between groundwaters from bedrock and eskers in Northern areas. K. H. Renlund Foundation, PI Hannu Marttila

Pertti Ala-aho is a Postdoc at University of Oulu and investigates the environmental importance of snowmelt water in the Arctic and other snow-influenced regions. He gained his PhD in 2014, and has since worked in international collaborations in Alaska, Siberia, Canada, Scotland, and Scandinavia. Ala-aho combines numerical modeling with stable water isotope tracer techniques to track snow along its journey from origin (oceans) to snowmelt and its role as ecosystem water source.


Hannu Marttila is a Senior Research Fellow and leading Northern Hydrology group at Water, Energy and Environmental Research Unit in Oulu. His research focuses on hydrological processes and catchment management issues in northern landscapes with strong cross-disciplinary work across science fields. Marttila has been participating and managed several Academy of Finland, EU and foundation based projects. He is a chairman in Hydrology division at Finnish Water Association and hydrology subject editor for Boreal Environmental Research Journal.

YHS interview Thorsten Wagener: being the head of a research group is “a bit like being a football coach”

In its “Hallway Conversations” series, the Young Hydrologic Society has recently published an interview with Thorsten Wagener, who is currently professor and the head of the Water and Environmental Engineering research group at the University of Bristol, UK. The interview was conducted by Wouter Knoben, a PhD student at the University of Bristol. With their agreement, we reproduce below some short extracts of the interview. For the full interview, visit the YHS Blog (here).

What’s an unusual place where you find inspiration for yourself or the work you do?

Football! Playing (in the past), watching and reading about it. [Points at bookshelf] that’s my football bookshelf. My current role, as Professor and Head of a research group that includes 9 academic staff and many more students and postdocs, is – at least in my head – a bit like being a football coach. Your team is a group of highly talented individuals who have all self-selected to be here as top people in their own right (like a professional football team). The role of the coach is to get them all to somehow work together or at least benefit from each other, without losing the chance to shine individually. So, I have a whole bunch of books written by or about football coaches on my shelf. Including “My Turn” by Johan Cruyff, “Quiet Leadership” by Carlo Ancelotti and “Leading” by Sir Alex Ferguson. Teams follow coaches because they believe that the direction the coach suggests will bring them success. There is a need to be convincing, genuine as well as caring – otherwise players will not believe that you want them to succeed, but that maybe you are only looking for short-term success for yourself. That’s more the Mourinho strategy, which always fails after a couple of years when players get disillusioned. I try not to do that here but try for everybody to benefit from the group.

Could you share any insights on how you approach creativity? Do you think that creativity and success are correlated?

Creativity is a bit under-appreciated in research, I think. I like learning about how creativity is approached in other fields. There is an excellent book called “Creativity Inc.” by the former President of Pixar, Ed Catmull. He discusses how they spend decades trying to optimise their creative process. They decided that everybody should share ideas early, so that bad ideas would fail quickly and not waste time, and that they needed to create continuous opportunities for feedback and involvement of everybody. We, in science, often see creativity as a by-product when it really is the essence of research. We often see it as a gift that one has or does not have, rather than something that can be significantly improved and nurtured. I think that in research, success and creativity are closely related and that everybody can improve their ability to be creative. I think that the most influential hydrologists are also the most creative. People who I admire for their creativity include (but are of course not limited to) Hoshin Gupta, Keith Beven, Chris Duffy or Brian McGlynn. Very different personalities, all of them (apart from maybe Chris Duffy) not the best students during their undergraduate degrees, but very creative people who can think outside the box and in a different direction than the rest. I think the distinction between short-term and long-lasting scientific contributions is often due to differences in creativity, but I should stress that it is not just that. Others succeed through their energy, through their persistence or depth of knowledge.

What are the biggest challenges and opportunities for hydrologists in the next 10 years or so?

One big challenge is that we need to not lose track of the large societal questions. Hydrologic understanding was and is the foundation for our survival and for sustainable development. Without water, there is no energy, no food, no clothing. The spreading of many infectious diseases is closely coupled to the water cycle. We cannot understand most local climate change impacts without understanding hydrology. There are many opportunities for hydrologic knowledge to contribute to society.
However, hydrology is also complicated because the closer you look at our environment, the more complex it becomes. So, as hydrologists we have long focused on understanding this complexity. Now, we need to start tackling the big problems and clearly separate the work on technical details (regardless of whether this is related to models or measurements) and focus on big societal questions. We are very good on tackling the former; we have historically been rather poor in identifying the latter (including the role of hydrology in understanding them). People like Tom Gleeson or Mark Bierkens have shown that we – as hydrologists – can identify big scale problems and provide answers – though they might be more approximate than what we can say about specific catchments. Don’t get me wrong. I am not suggesting that we focus only on this, but that we simply have to do significantly more of this type of work. Here is where we need to be more creative: in identifying interesting and relevant problems and questions – as well as solutions.

Read the full interview in the YHS Blog (here).

EGU is a bit like a music festival: first time experience of an ECS in hydrology

EGU is a bit like a music festival: first time experience of an ECS in hydrology

EGU is a bit like a music festival. Maybe not as crowded as the Donauinselfest, but you’ll definitively experience some of this type of event classic features: dilly-dallying a lot about what to see next, losing your friends and setting up more or less detailed meeting points, buying overpriced food and beverages. And if in the right place at the right time, you might even see some actual “rock stars”!

Me and my Mentor!

EGU is a lot of people and a lot of contents squeezed into one week! Now it can be quite unsettling for newcomers, but here’s some points to demystify the beast.

Despite the ants-like flow in the hallways, EGU recovers human dimensions during each oral session, with an average attendance of about 40 people for what I could experience. It’s something to have in mind when getting nervous about your own scheduled presentation if there’s any.

Half of people is like you, meaning young scientists, eager to share and help each other. And fortunately, the other half is just the same, with more experience and possibly less hair that’s all. Communicating is very easy at EGU, with all kind of researchers (age-wise, country-wise, topic-wise). That’s probably the main purpose of it and the main reason you should come.

There’s also a bunch of events and special groups intended for facilitating new scientists’ integration: Sunday evening Ice-breaker, Early Career Scientists lounge, short courses and workshops and social evening events, etc. In particular, when registering for the EGU General Assembly, you’ll be asked if you want to be part of a Mentoring program. Say yes and you’ll be put in touch with a more experienced participant that’ll give you further advice and with whom you can meet easily throughout the week. I experienced this mentoring to be a good way to get comfortable in the unfamiliar terrain of such a big conference!

Now, how to make the most of this week you may wonder. Well there is no right answer to that I suppose, but here’s some input.

Red poster hall – the heart of hydrology during the EGU week.

Quoting approximately the EGU’s president introduction speech, go beyond your own field of research. It would be a shame to spend a whole week focusing on what you’re working the rest of the year anyway, when so much is at hand. As for myself (doing a PhD on computational methods in hydrogeology), I attended sessions about surface water quality, erosion processes, ecology, geothermal resources, or science-politics linkage (this last inspired me some thought that I’ll may be able to share with you later). At some point lost in the program and venue, I even stumble about a speech about hyper arid environments, where I heard that some place in Chile receive less than 1 mm of precipitation a year… things you learn when you get lost!

And to conclude, you might feel obligated to spend 10 hours a day in the Vienna International Center, with regard to the plethoric program. Well I do think that it should be judged by your own ability to concentrate and digest information in a little amount of time. As far as I’m concerned, I chose not to fully book every day with session, sparing some time to rest, wander and visit! Mind that Vienna is a key European historical and cultural center: the apogee of classical and romantic music genres, one of the birthplaces of modernism in painting and architecture, a land of authors and philosophers to be discovered.


Guest-author Dimitri Rambourg attended this year’s EGU General Assembly the first time and he shares his impression. He is a PhD student at Laboratoire d’Hydrologie et de Géochimie de Strasbourg (LHYGES).