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Community advice to young hydrologists, Part 1

Community advice to young hydrologists, Part 1

We at Water Underground loved reading Young Hydrologic Society’s post titled “Community advice to young hydrologists” – an advice column written by a network of established scientists in the field. We appreciated the column so much, in fact, that we have decided to re-blog the post to you (with YHS’s consent, of course). We’ve split up their post by question, and have added in hyperlinks to all contributors and related material (as has always been our inclination). Happy reading!

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Question: What book or paper has been most influential to your career and why?

Groundwater by Freeze and Cherry – this textbook, now out of print, was a critical reference as I began my graduate training in hydrogeology and I still refer to it today.

Jean Bahr (University of Wisconsin)

 

 

 

 

 

 

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I can think of no single one.  However, papers that were a combination of field observations and clever analyses leading to new insights always are intriguing.  Papers which I find of little value are those that propose a new modeling approach with little to no field verification, or which use existing models to reach some conclusion.  For example, we seem to be seeing a proliferation of papers using complex models to highlight some “new” effect of climate change on the hydrologic cycle, with no grounding in hindcasts. (See this, also) The musings of Keith Beven always have been insightful, including his Advice to a Young Hydrologist.

Jerad Bales (CUAHSI)

 

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I can’t identify single “most influential” books or papers – I learned early to read as widely as possible, and not just within narrow/specific research problems of direct interest. I have been inspired by a range of articles – including books on philosophy, history of physics, etc. – which broadened my approach and ways of looking at a given problem. Indeed, some of my most influential work developed from studying methods and approaches in statistical physics and physical chemistry.

Brian Berkowitz (Weizmann Institute of Science)

 

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The most important influence was a person – Mike Kirkby and particularly the undergraduate course on quantitative hydrology he taught at the University of Bristol when I was taking my degree there (later, I would do a post-doc with him at Leeds that resulted in the development of Topmodel). That gave me a lot of reading to do – but it was probably not the hydrological reading that had most influence, but rather the papers on theoretical geomorphology starting with Horton BGSA 1945, then picked up by Kirkby, Frank Ahnert and others in the late 1960s. I struggled to understand them (at the time I wanted to be a geomorphologist but I have never quite finished getting the water part right) but they left me the idea that it was possible to theorize about environmental processes and systems in approximate but useful ways.

During my PhD the most influential paper was undoubtedly Freeze and Harlan JH 1968, and the papers about the field site I was applying my model to by Darrell Weyman (HSB 1970, IAHS 1973). If I had talked to him a little more (he was doing his PhD at Bristol while I was an undergraduate) or read those papers more carefully, then I might have been more realistic in my PhD modelling.

The most important book at that time was Zienkowicz, Finite Element Modelling (that was the technique I was trying to master). Hillslope Hydrology edited by Kirkby was also important but came later.

Keith Beven (Lancaster University)

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Paper: Scale of Fluctuation of rainfall models by I. Rodriquez-Iturbe. It formed the basis for my MSc research that I did during 11 months in Davis California (As a Dutch Student from Wageningen). It was extremely difficult stuff, but I kept on it and it understanding gave me the stamina to really dig into a subject. It was the basis for my first paper entitled “Analytically derived runoff models based on rainfall point processes” in WRR. To obtain better background I also read in depth the influential.

Book: Random Functions and Hydrology by R. Bras and I. Rodriquez-Iturbe.

Marc Bierkens (Utrecht University)

 

 

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Dooge’ 1986 Looking for hydrologic laws in WRR. This paper gives a broad perspective on science, including scales.

Günter Blöschl (TU Vienna)

 

 

 

 

 

 

 

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Konrad and Booth (2005), Hydrologic changes in urban streams and their ecological significance, American Fisheries Society Symposium, 47:157-177.  This paper is a bit outside my area of expertise, but I think the linkage they make between physically measurable streamflow changes and stream ecology represents a fundamental shift in thinking from engineering hydrology to more of an eco-hydrology perspective.  They illustrated that we need to go beyond analyzing just changes in peak flow or low flows (or fixed percentiles), to look at more derived metrics that better capture hydrologic regime change.

Laura Bowling (Purdue University)

 

 

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That is a very hard question. As a Geography undergraduate student, I had to write a particular essay on the “all models are wrong” theme and this involved critiquing two papers which completely changed my worldview about models and modelling: Konikow and Bredehoeft’s 1992 ‘Ground-water models cannot be validated’ Advances in Water Resources 15(1):75-83.  and Beven’s 1989 ‘Changing ideas in hydrology – the case of physically-based models’ Journal of Hydrology.

But in the last year, I would say it has been Lab Girl by Hope Jahren (2016) who is a gifted and talented scientist and writer and has the knack of intertwining the natural world with tales of remaining brave in your career. I wish I’d had the opportunity to read it earlier in my career.

Hannah Cloke (University of Reading)

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Ecological and General Systems – H.T. Odum. This book explores general systems theory in the context of ecosystem behaviors. It is holistic, comprehensive, and full of important insights about the structure and dynamics of systems.

Matthew Cohen (University of Florida)

 

 

 

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It is a novel by Milan Kundera: “Slowness”. My natural tendency is to rush up, be as fast as possible, quickly fix things… Yet, speed often leads to miserable outcomes. Many lines of Kundera’s book are still in my mind, and they work as a continuous reminder for me that only slowness allows thoughtful consideration, serious reflection, and appreciation of reality. Realizing this has strongly influenced my academic career as it made me focus on the quality (and not the quantity) of my work.

Giuliano Di Baldassarre (Uppsala University)

 

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Several hydrogeology-related texts were very helpful for me.  These include some of Mary Hill’s papers, John Doherty’s PEST manual (as much for the philosophy as the instruction), some of Jasper Vrugt’s early papers, and work by both Wolfgang Novak and Steve Gorelick on measurement design. The real recommendation would be to find authors that you enjoy and read as much of their work as possible – in this category, I would add Shlomo Neuman, Randy Hunt, Hoshin Gupta, Dani Or, Keith Beven and Graham Fogg. I am sure that I am forgetting more than I have listed. I think it is equally important to read broadly. Rather than provide a list, I’ll encourage you to look at my recent paper in Ground Water (Sept 2016) for some suggestions!

Ty Ferré (The University of Arizona)

 

 

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Book:  Groundwater Hydrology by David Keith Todd, 1st edition, 1959. As a 3rd-year undergraduate in hydrology at the University of New Hampshire in 1973, this book (and course by Francis Hall) kindled my interest in groundwater and completely changed my career path, which previously was essentially an aimless sleepwalk through my major in mathematics.

Paper/report:  Kaiser, W. R., Johnston, J. E., and Bach, W. N.. 1978, Sand-body geometry and the occurrence of lignite in the Eocene of Texas: The University of Texas at Austin, Bureau of Economic Geology Geological Circular 78-4, 19 p.  This paper demonstrated in stunning detail how modern borehole geophysical data together with understanding of the geologic genesis of sedimentary deposits could be used to create unprecedented subsurface maps of aquifer/aquitard system heterogeneity and structure. This led me down the long path of better integrating groundwater hydrology and geologic depositional systems.

Graham Fogg (UC Davis)

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My interests have been in predictive hydrometeorology. The following were influential books at the start of my carrier in the late 70s and early 80s: Dynamic Hydrology by Eagleson; by Wallace and Hobbs; Applied Optimal Estimation by Gelb (ed).  These represented the fields of hydrology, meteorology, and estimation theory with applications to prediction, and were the necessary pillars to build predictive hydrometeorology.

Konstantine Georgakakos (Hydrologic Research Center in San Diego)

 

 

 

 

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Haitjema and Mitchell-Bruker (2005) which taught me to think of groundwater as a process that interacts with topography, climate and geology in complex but predictable ways.

Tom Gleeson (University of Victoria)

 

 

 

 

 

 

 

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The paper that has been most influential to my career is most certainly  “Johnston, P. R., and D. H. Pilgrim (1976), Parameter optimization for  watershed models, Water Resources Research, 12(3), 477–486. I read this paper during my graduate work in the early 1980’s and was intrigued by their report that “A true optimum set of (parameter) values was not found in over 2 years of full-time work concentrated on one watershed, although many apparent optimum sets were readily obtained.”

On the one hand this paper clearly identified an important problem that needed to be addressed. On the other (as I often remark during talks on the subject), I think it was remarkable as an example of a paper reporting the apparent “failure” of the researchers to achieve their goals … how often do we see people reporting their failures in the literature these days :-). More of this kind of work – reporting a scientific study and accurately reporting both successes and failures … but especially failures … is critically important to the progress of science, so that people can both contribute to solutions and also avoid unsuccessful forays down paths already tried.

In any case, the paper clearly pointed me towards an important problem that led to me adopting a path of research over the past decades, which led to the development of the SCE and SCEM  optimization algorithms (and indeed a whole field of optimization developments), studies into impacts of model structural deficiencies, multi-criteria methods for parameter estimation, the diagnostic model identification approach, and more recently the Information Theoretic approach.

The 1990 paper by Michael Celia et al on the numerical solution of Richards equation, recommended to me by Philip Binning at the beginning of my Honours Project at Newcastle Uni. This paper made a big impression on me because it provided a very clear exposition of how to solve a challenging modelling problem – and played a bigly role in getting me interested in research.

Dmitri Kavetski (University of Adelaide)

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The Ecological Studies Series, published by Springer, was the most influential in my career because several books published in the Series (e.g., Forest Hydrology and Ecology at Coweeta edited by Swank and Crossley and Analysis of Biogeochemical Cycling Processes in Walker Branch Watershed edited by Johnson and Van Hook) sparked my interest in forest hydrology and biogeochemistry. In tandem with the superb mentorship of Prof. Stanley Herwitz (Clark University), I decided to embark upon a career as a forest hydrologist as a sophomore in college. I never looked back.

Delphis Levia (University of Delaware)

 

 

 

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The papers of the series “Plants in water-controlled ecosystems” (2001, Advances in Water Resources 24), by Laio, Porporato, Ridolfi, and Rodriguez-Iturbe have been among the first and most influential I have read. Their clean, analytical approach to the complex interactions among vegetation, soil, and climate remains deeply inspiring. As an example of inter-disciplinary work (actually outside hydrology), I would like to mention the book by Sterner and Elser (2002) “Ecological stoichiometry. The biology of elements from molecules to the biosphere” (Princeton University Press) – a great example of how integrating knowledge from various sources around a common theme can yield deeper understanding and perhaps even lay the foundation of a new discipline.

Stefano Manzoni (Stockholm University)

 

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The Hewlett and Hibbert 1967 conference paper “Factors affecting the response of small watersheds to precipitation…” is perhaps the best paper ever written in hydrology. For a full homage, please look here. The paper is field-based, theory focused and a blend of bottom-up and top-down research, before that was even ‘a thing’. It inspired me in my graduate research in the 1980s; I continued to read it and ponder it in my first years as a professor, as I strived to follow in Hewlett’s footsteps. He was my mentor even though he retired before I could ever meet him.

Jeff McDonnell (U Saskatchewan)

 

 

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 In general, the books that have been most influential to me refer to sister disciplines. The reason is that I found illuminating to study methods and models used in statistics and economics for the purpose of applying them to hydrology for the first time. Thus, the most influential book to me has been “Statistics for long-memory processes”, by Jan Beran. The very reason is that I found there a detailed explanation of models that were useful to get to target with my Ph.D. thesis. 

Alberto Montanari (University of Bologna)

 

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Chamberlin TC. 1890. The method of multiple working hypotheses. Science 15: 92-96 (reprinted in Science 148: 754–759 [1965]). I read this paper as part of a second-year course in Archaeology, which I took as an elective in my undergraduate program. Although the writing style is somewhat archaic, this article introduced me to the value of hypothesis-based thinking in science and the need to avoid favouring a pet hypothesis or model. It is instructive also to read the many follow-up essays to gain a broader perspective on hypothesis-based research and, more broadly, the “scientific method.”

Dan Moore (University of British Columbia)

 

 

 

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I think I was more influenced by my peers, colleagues, mentors, supervisors and friends as I learn better through discussions and challenges. One of the more memorable papers is one of Manning (Manning, R. (1891). “On the flow of water in open channels and pipes,” Transactions ofthe Institution of Civil engineers of Ireland.) and it’s associated history. In this paper he actually suggested a far more ‘complex’ formulation than the formula which is today widely known as the Manning equation – history has it that it was never adopted widely as well as many subsequent more more sophisticated formulations. Science doesn’t work linear and we are sometimes less rational or objective (if the latter is actually possible) than we believe.

Florian Pappenberger (ECMWF)

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“Show me a person who has read a thousand books and I’ll show you my best friend; show me a person who has read but one and I will show you my worst enemy.” I have been influenced by many and I can’t say one is *the* most influential or important alone.  At the moment, I am reflecting on (McCuen RH. 1989. Hydrologic Analysis and Design. Prentice Hall: Englewood Cliffs.) As far as being a hydrology textbook it is not particular special, but it is written extremely clearly with a lot of good step-by-step workflows.  Most importantly, the book integrates throughout its whole development the concept of analysis versus synthesis, and this has been central to how I approach my research.  We do both analysis and synthesis.

Gregory Pasternack (UC Davis)

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This is very difficult to say. I must admit that my academic work started from engineering practice and I only started reading the international literature very late in my career. But a book that has been very influential to me was the book by Fischer et al. (1979) “Mixing in inland and coastal waters”. Fischer soon died in an accident after this book was published. The book introduced me to the fundamentals of mixing processes in estuaries, on which I had done substantial field research and had developed my own practical engineering method, which I still use, but which lacked a fundamental theoretical basis. I am still working on finding this fundamental basis, and Fischer’s book put me on that track.

Hubert Savenije (TU Delft)

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It would be tough to answer what’s been the most influential to my career as a whole, but I could answer what was the most influential to my early career, and that was Menke’s Geophysical Data Analysis: Discrete Inverse Theory.  I labored through that book for years during my PhD. My copy has dog-eared pages and writing throughout as I tried to figure out inversion methods.  Finally getting my head around the mathematics of inversion really opened up some doors for me early on.  Davis’ Tools For Teaching also really helped me think about how to be as effective a teacher as I could be.

Kamini Singha (Colorado School of Mines)

 

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Books are hardly ever influential once you are actually ‘in’ research. Early on, look for the best review articles in your field. They will ‘set the scene’ for you.

Keith Smettem (The University of Western Australia)

 

 

 

 

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Opportunities in the hydrologic sciences”, National Academy Press. This landmark book which defined hydrology as a science appeared right at the start of my PhD. It provided a nice framework for my own research and that of my fellow PhD students in those days.

Remko Uijlenhoet (Wageningen University)

 

 

 

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It is difficult to select one single work from the literature that has been influential over my entire career in groundwater flow and transport modeling.  But, there is one book that I used as a grad student that I still refer to today.  It is “Conduction of Heat in Solids” by Carslaw and Jaeger.  The book is a treatise on analytical solutions to diffusion equations.  The lesson for me is that knowledge from other disciplines (in this case thermal engineering) can be applied to problems in hydrology.  Another lesson is that we can learn a lot and gain important insights through wise approximations that have analytical solutions.

Al Valocchi (University of Illinois at Urbana-Champaign)

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Abramowitz & Stegun: Math is something you look up, not something you try to memorize.

Nick van de Giesen (TU Delft)

 

 

 

 

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In hydrology, some of the most influential books for me have been Handbook of Hydrology (edited by David Maidment) and Principles of Environmental Physics (Monteith & Unsworth). These two books are so rich in physics, empirical equations, recipes, and references. Of course the times have changed and nowadays you can google almost anything, but some of the chapters in these books are so well written that I still regularly use them. They also have the benefit that they summarise areas of research where things haven’t actually changed too much since the 80ies – the physics we use haven’t become that much more sophisticated, and sometimes in fact less so; whereas the field measurements on which a lot of the empirical rules and equations are based generally also haven’t been added much to since.

Outside hydrology, some books that have made me think differently about the field and my research include

Emergence: The Connected Lives of Ants, Brains, Cities, and Software (Johnson) – one of the first popular science books I read that made me think different (about ecohydrology)

The Sceptical Environmentalist (Lomborg) – I didn’t accept his reasoning but it was seductive and it forces you to really pick apart the logical and rhetorical flaws he uses.

Thinking, fast and slow (Kahneman) – which really made me realise the questionable quality of my analytical rigour and decisions in general (also those of anyone else, though!).

Albert van Dijk (Australian National University)

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Physical Hydrology by Dingman and Elements of Physical Hydrology are both great textbooks. Why: just lots of “basics” well explained, emphasizing the need to understand PROCESSES.

Doerthe Tetzlaff (University of Aberdeen)

 

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House at Pooh Corner, specifically, Chapter VI. In which Pooh invents a new game and Eeyore joins in.  The first paragraph is an awesome description of a classic watershed and affirms my theory that hydrology is truly everywhere… even on Mars.  Indeed, the search for “life” has largely been a search for “water.”

Todd Walter (Cornell University)

 

 

 

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Comparative hydrology, edited by Malin Falkenmark and Tom Chapman (1989). This book is one of the first to examine global hydrology phenomena. It asserts that a comprehensive and systematic description of hydrological processes is (i) possible (ii) not too complicated. Until then I’d thought the task was impossible, so I found the approach inspirational for my research.

Ross Woods (University of Bristol)

Where does the water in streams come from when it rains?

Where does the water in streams come from when it rains?

Post by Anne Jefferson, associate professor in the Department of Geology at Kent State University, in the United States.

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The title of this blog post might seem like a question with an obvious answer, or even a silly question to pose on a blog devoted to groundwater, but if you don’t see the connection between streamflow and underground water, you need to keep reading.

Water in streams during storms does come from the sky, but often it’s not the water droplets falling in a particular rain storm that are going rushing down the stream during that storm. Very little precipitation falls directly on the stream channel, because streams occupy very little of the landscape. So most water in a stream has to travel over or under the ground to get there. Traveling from some random point in a catchment to a stream takes time, and there are usually other water molecules between the freshly fallen raindrop and the channel.

Water molecules that can’t infiltrate into the ground become surface runoff. Surface runoff tends to reach the stream channel fairly quickly, because the water molecules encounter much less flow resistance than water moving through soil or bedrock and because all of the other water molecules between them and the stream are also on the same downhill express lane to the stream. So a water molecule that becomes surface runoff can reach a stream minutes to hours after the raindrop first hit the land surface.

On the other hand, raindrops that infiltrate into the ground take a much more leisurely approach to reaching the stream. Underground, flow resistance is really high, relative to what surface runoff encounters, because the water molecules have to squeeze through tiny and tortuous open spaces between soil particles, roots, and rock. They may even be trapped by capillary forces or stick to mineral or organic surfaces. Plus, underground, there are lots of other water droplets also slowly making their way to the stream. Being a water molecule that goes underground to reach a stream is not so much taking an express lane, as joining the back of a barely moving traffic jam that stretches as far as the eye can see. In the minutes, hours, and days during which a stream runs high following a rainstorm, that poor underground water molecule may only have moved a few meters to a few hundred meters toward the channel. Indeed, its main function in joining the back of the traffic jam was to give a pressure wave nudge to the water molecules closer to the channel, urge them to get a move on, and increase the rate they discharge into the stream.

With those general concepts in mind, let’s turn our attention to humid, forested landscapes. Most rain will infiltrate into the soil, disappear underground, and join the back of the traffic jam. As a consequence, when we look at the water rushing along in a stream channel, during or shortly after a storm, mostly we are not seeing water that fell from the sky in the storm. We’re seeing the ghosts of storms past. Catchment hydrologists call this “old” water. To put some numbers on it, 60-80% of the volume of streamflow during and immediately following a storm is typically old water. Even at the peak of the streamflow, ~50% of the water in the stream is old water.

The Cuyahoga River in Kent, Ohio under low flow conditions, October 2017.

The Cuyahoga River in Kent, Ohio, at high flow, March 2014.

How did hydrologists figure out that the water in streams during storms is old water (at least in forested landscapes)? It would be virtually impossible to go out to a catchment and measure the water flowing across all possible surface runoff, soil water, and groundwater paths.

Wouldn’t it be convenient if there was some way to label the water molecules as new or old and then just count the ratio of new to old water molecules in the stream at a given time? Fortunately for hydrology, variations in the isotopes of hydrogen and oxygen in the water molecules provide just such a tracer. Beginning in the late 1960s, hydrologists realized that they could use the storm-to-storm differences in the isotopic ratios of rainfall to identify water that came from the most recent storm versus water that didn’t. Thus the technique of isotope hydrograph separation was born. The popularity of the method grew rapidly, hydrologists began to try it out in catchments all over the world. This led to more recent work carefully laying out the assumptions and limitations associated with the technique and developing ever more sophisticated methods of analysis. Even more important than the method itself was that hydrologists, confronted with the reality that most of the water in the stream during a storm was old, had to then come up with mechanistic explanations for how that was possible. I don’t think it’s hyperbolic to say that isotope hydrograph separation really helped revolutionize the field of catchment hydrology.

When I teach hydrology, I teach students that in our forested corners of Ohio the water in the stream during storms is old and I explain the mechanisms. But I also think it’s important for them to understand the technique that helped generate those insights, and so I make sure to teach them about isotope hydrograph separation. With the support of an NSF grant, I developed a teaching module that gives students a chance to work with real data and do their own hydrograph separation. My hope is that the exercise will give them a deeper appreciation of the technique, the assumptions and uncertainties it contains, and the insights it is able to provide. This teaching module is available on the SERC website for anyone to use in classes or just for fun. There are data to download, step-by-step directions, and links to related readings. If this post has spurred your interest in streamflow generation or isotope hydrograph separation, I encourage you to check it out. Other good places to learn more about applications of isotopes in hydrology at the SAHRA website or in this book chapter by Kevin McGuire and Jeff McDonnell.

Kent State students measuring discharge in the stream where we conducted the hydrograph separation.

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Anne Jefferson is an associate professor in the Department of Geography at Kent State University. Anne‘s research focuses on watershed hydrology, groundwater-surface water interactions, and landscape evolution in human-altered and volcanic landscapes. Current projects of her’s focus on green infrastructure, stormwater management, and stream restoration. Keep up to date with Anne by clicking on any of the links below:

Research profile | Twitter | Personal Website

What is the difference between ‘water withdrawal’ and ‘water consumption’, and why do we need to know?

What is the difference between ‘water withdrawal’ and ‘water consumption’, and why do we need to know?

Post by Inge de Graaf, University of Freiburg, Environmental Hydrological Systems group

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Last week I had to teach my first class in global hydrology. When I showed the global trend on increasing demands and withdrawals (see Figure) I needed to explain the different terms as sometimes the term “water use” gets, well, misused.

The term “water use” often fails to adequately describe what happens to the water. So I told the students; if you see or hear to term ‘water use’ always ask yourself what’s actually being said. The term is often used for water withdrawals or water consumption, and it’s important to understand the difference.

Water withdrawal describes the total amount of water withdrawn from a surface water or groundwater source. Measurements of this withdrawn water help evaluate demands from domestic, industrial and agricultural users.

Water consumption is the portion of the withdrawn water permanently lost from its source. This water is no longer available because it evaporated, got transpired or used by plants, or was consumed by people or livestock. Irrigation is by far the largest water consumer. Globally irrigated agriculture accounts for 70% of the total water used and almost 50% is lost either by evaporation or transpiration.

Understanding both water withdrawal and consumption is critical to properly evaluate water stress. Measurements of water withdrawal indicate the level of competition and dependence on water resources. Water consumption estimates help to quantify the impact of water withdrawals on downstream availabilities and are essential to evaluate water shortage and scarcity. For example, most water used by households is not consumed and flows back as return flow and can be reused further downstream. However, water is rarely returned to watershed after being used by households or industry without changing the water quality, increasing water stress levels.

Already more than 1.4 billion people live in areas where the withdrawal of water exceeds recharge rates. In the coming decades global population is expected to increase from 7.3 billion now, to 9.7 billion by 2050 (UN estimate). This growth, along with rising incomes in developing countries, is driving up global food demands. With food production estimated to increase by at least 60% (FAO estimate), predicting water withdrawal and consumption is critically important for identifying areas that are at risk of water scarcity and where water use is unsustainable and competition amongst users exist.

Global trend I showed in my class, published in Wada et al (2016).

Ref:

Wada, Y., I. E. M. de Graaf, and L. P. H. van Beek (2016), High-resolution modeling of human and climate impacts on global water resources, J. Adv. Model. Earth Syst., 8, 735–763, doi:10.1002/2015MS000618.

 

FloPy: A Python interface for MODFLOW that kicks tail!

FloPy: A Python interface for MODFLOW that kicks tail!

Authored by: Kevin Befus – Assistant professor, Department of Civil and Architectural Engineering at the University of Wyoming


Groundwater modeling is getting better. Models are becoming more sophisticated with simpler interfaces to add, extract, and process the data. So, at first appearances, the U.S. Geological Survey’s (USGS) recent release of a Python module named FloPy for preparing, running, and managing MODFLOW groundwater models seems to be a step backwards.

Oh, but it isn’t.

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First, a couple disclaimers. Yes, at the time of writing this I work for the USGS and use this new Python module for my research. Did I have to use FloPy? No. Am I glad I did? YES! Before using FloPy, I dabbled in the various non-commercial MODFLOW interfaces but got bogged down on how many drop down menus, pop-up menus, wizards, and separate plotting programs with their own menus were needed to make a meaningful groundwater model on top of a new lexicon of variable names (IUPWCB must mean “internally unknown parameter with concentrated bacon”, right?).

FloPy made its official debut in February 2016 with a Groundwater methods report 1. Bakker et al. do an excellent job telling us why we should use FloPy. I’ll leave that to you and tell you what I think.

Here’s what is great about FloPy:

  1. FloPy is 100% MODFLOW. No tweaks to anything. You choose the executable file you want it to use or compile it yourself, and you’re off!
  2. You have the near-infinite data management, manipulation, and plotting capabilities of Python at your fingertips. Python has a lot of packages. It can be overwhelming. You can rely commercial packages like ESRI’s arcpy if you want, but there’s a list of free libraries that give you even more freedom to get the input data just right. Since I mentioned freedom, here’s the list of free libraries I find useful but it is in no way an endorsement nor exhaustive: scipy, numpy, gdal, osgeo, fiona, shapely, cartopy, pyshp, pandas, matplotlib, and let’s not forget…flopy!
  3. It’s easy to duplicate and alter an existing model. Once you have your script perfect for running a particular groundwater model, you can take pieces of it to make a slightly altered version, or you can pop it in a loop that runs through your uncertain inputs for sensitivity testing. Change your grid with the flip of a variable, and make sure that mesh converges!
  4. Loading other MODFLOW models works great. Say you want to run someone else’s model with slightly different recharge, but their recharge is variable in space. Since FloPy incorporates numpy’s grid/matrix handling capabilities, you can change individual entries with row-column selections or change the whole recharge grid by multiplying it by either a single number or say a random matrix with a normal distribution and some added noise. If you just want to use their recharge data to run your own model, you can save the position coordinates (they have hopefully provided you with their coordinate system and model transformations) and recharge arrays to your very favorite format (csv, nc, mat, tif) and load it later as a matrix to add to your model, all in a single Python script.
  5. Building off of the ability to load or create MODFLOW models, FloPy has functions for plotting 2D map or cross-section views of the model discretization, boundary conditions, and results. Shapefiles can be included in these plots if they are in the same coordinate system as the model or extracted from the model (ever want a polygon feature of every model cell with attributes for every property of that cell?). I do my own shapefile manipulations in Python, but FloPy has some great plotting tools built in.
  6. You already have the data in Python. See what adding a low permeability layer does to spring discharge. Then, with the model made, you have to make sense of it. Maybe develop some interesting spatial or time series analyses. Enter Python. Plotting with matplotlib also makes beautiful, journal article-worthy figures…with enough sweat and tears from your end (not as many as you may think). Yes, this is a repeat of 2), but, seriously, it’s in PYTHON!
  7. FloPy is totally free. Python is free. Tons of science-oriented libraries in Python are free.

KB2.JPG

Here’s a flashy example.  It is straightforward and only takes one script to create a SEAWAT model from scratch and plot the 2D steady state salinity distribution and flow vectors for a simple Henry 2 problem based on a slightly edited FloPy example script.  There are more than a dozen example scripts available on the FloPy site as well as a very cool capture ratio script provided in the methods report 1.

For the groundwater educators out there, a FloPy groundwater model script can be paired with homework questions that get students testing how changing hydraulic conductivity in certain parts of the model changes the water table configuration. Or maybe a new well needs to be drilled on a plot of land near a spring… The scenarios are endless. Students can develop a fundamental understanding of groundwater flow while getting experience with both groundwater modeling and computer programming. Win, win, and win.

Essentially all of the standard MODFLOW packages are operational in FloPy, and there are varying levels of support for some of the specialized MODFLOW compilations and processing tools (e.g., MODFLOW-USG, MODFLOW-NWT, MT3DMS, SEAWAT, PEST, and MODPATH). PEST and MODPATH are currently not executable with FloPy, but these features will probably be added in a future release (I have made my own klugy modules for running ZoneBudget and MODPATH that interface reasonably well with the rest of FloPy).

Get on your way and give FloPy a try today!


Links

The Python package is available online at https://github.com/modflowpy/flopy.

The documentation is available online at http://modflowpy.github.io/flopydoc/index.html.

The USGS FloPy page is http://water.usgs.gov/ogw/flopy/.


References

Bakker, M., V. Post, C. D. Langevin, J. D. Hughes, J. T. White, J. J. Starn, and M. N. Fienen (2016), Scripting MODFLOW Model Development Using Python and FloPy, Groundwater, doi:10.1111/gwat.12413.

Henry, H.R., 1964. Effects of dispersion on salt encroachment in coastal aquifers. In: Cooper, H.H. (Ed.), Sea Water in Coastal Aquifers: U.S. Geological Survey Water- Supply Paper 1613-C p. C71–C84.


About the author:

Kevin Befus is a groundwater hydrologist with geology and geophysics experience — examining geological, biological, and chemical processes, especially considering their connections to water across scales.

KB3

One hell of a great groundwater textbook now available free

One hell of a great groundwater textbook now available free

‘Groundwater’ the seminar text book from Freeze and Cheery (1979) is free in pdf now…just follow the links here. This text book is almost as old as I am and important parts of modern hydrogeology are rusty or non-existent (like hydroecology amongst other topics) but it is still lucidly written and useful.  I routinely send students to read chapters so I am happy that it is now available free.

Kudos to Pearson Publishing, Alan Freeze and John Cherry and Hydrogeologists without Borders! I look forward to Groundwater2.0 which is in the works!

 

 

The new and exciting face of waterunderground.org

The new and exciting face of waterunderground.org

by Tom Gleeson

I started waterunderground.org a few years ago as my personal groundwater nerd blog with the odd guest post written by others. Since I love working with others, I thought it would be more fun, and more interesting for readers, to expand the number of voices regularly posting. So here is the new face of the blog…

http://www.fragilestates.org/wp-content/uploads/2012/10/collective-action.jpg

a kind of weird image of collective action

What is the new blog all about?

Written by a global collective of hydrogeologic researchers for water resource professionals, academics and anyone interested in groundwater, research, teaching and supervision. We share the following aspirations:

  • approachable groundwater science at the interface of other earth and human systems
  • encourage sustainable use of groundwater that reduces poverty, social injustice and food security while maintaining the highest environmental standards
  • compassionate, effective supervision
  • innovative, effective teaching
  • transparency of scientific methods, assumptions and data

Check out more details and how to be part of the blog on about.

Frequent contributors include:

  • Andy Baker (University of New South Wales, Australia) – caves and karst (I actually visit the water underground!), climate and past climate
  • Kevin Befus (University of Wyoming, United States) – groundwater-surface interactions, coastal groundwater, groundwater age
  • Mark Cuthbert (University of Birmingham, United Kingdom) – groundwater recharge & discharge processes, paleo-hydrogeology, dryland hydro(geo)logy, climate-groundwater interactions
  • Matt Currell (RMIT University, Australia) – isotope hydrology; groundwater quality; transient responses in aquifer systems
  • Inge de Graaf (Colorado School of Mines, United States) – global groundwater withdrawal, flow and sustainability
  • Grant Ferguson (University of Saskatchewan, Canada) – groundwater & energy, regional groundwater flow, sustainability
  • Tom Gleeson (University of Victoria, Canada) – mega-scale groundwater systems and sustainability
  • Scott Jasechko (University of Calgary, Canada) – global isotope hydrology; groundwater, precipitation, evapotranspiration
  • Elco Luijendijk (University of Gottingen, Germany) – paleo-hydrogeology,deep groundwater flow,large scale groundwater systems
  • Sam Zipper (University of Wisconsin – Madison, United States) – ecohydrology, agriculture, urbanization, land use change

Can we use an infrared camera to tell us how much groundwater is coming out of the side of a cliff?

Can we use an infrared camera to tell us how much groundwater is coming out of the side of a cliff?

By Erin Mundy – a plain language summary of part of her Masters thesis

Groundwater is an important resource, with approximately 2 billion people around the world using groundwater everyday. Although most groundwater is beneath our feet, sometimes groundwater leaks out of stream-banks, hill sides and cliff faces – this is called groundwater seepage. Current scientific methods are not able to measure the amount of groundwater that leaks out of these landscapes. Scientists have used infrared cameras (cameras that show the heat of an objects) to identify groundwater seepage on hill-slopes and stream banks (Figure 1).

seep1

Figure 1. Digital image (a) and temperature image (b) of a seep in the summer and a digital image (c) and temperature image (d) of the same seep in the winter

This is because groundwater has an distinct heat signal, having a relatively constant temperature throughout the year (~10 degrees Celsius). Building on these studies, we hoped to find out the possibilities and limitations of using infrared cameras to measure the amount of groundwater that leaks out of the side of a cliff. We wanted to test if groundwater was flowing out of a cliff face slowly in the summer would warm up as it traveled down the rock, so the heat signature of the groundwater would go from cool water (that comes out of the rock, ~10 °C) to warmer water (warmed due to the sun and air temperature). On the other hand, we wondered if groundwater was flowing fast out of the cliff-face, it would not have time to warm, because the cool groundwater would be consistently running over it. In the winter, we believed the opposite would happen, that the groundwater would be warmer, relative to the surroundings, and show a cooling trend as the water traveled down the rock.

 

We found an unused mining pit in Saint Dominique, Quebec, that had lots of groundwater seeps coming out of the exposed rock, and used this as our test location. The mining pit had 3 different levels, as shown in Figure 2.

seep2a

Figure 2: an aerial shot of the quarry with the seeps labeled.

We took infrared and optical photographs of the seeps during seven visits that spanned from January 2013 – October 2014. Three visits took place during the winter (January – February 2013), coinciding with periods of below freezing so that the effect of extreme cold on seeps could be analyzed. Four visits took place during the summer/fall (June – October 2014), coinciding with sunny and hot conditions, and cloudy and warm conditions in order to determine the effect warmer temperatures have on seepage. In addition to these visits, we also completed a 24-hour experiment, where we took infrared pictures of two seeps every half hour for 24-hours, to determine the effect of sunlight and changing air temperature on the seep temperature signature. We also created an “artificial seep” experiment, where we released water from two large tubs over the cliff at the pit for 8 hours; one tub had water released at a slow rate, while the other at a faster rate, to see if we could replicate the heat signals from the real seeps. We took pictures with the infrared camera every half hour for eight hours for that experiment. We analyzed the infrared photos from each visit using a computer software that allowed us to determine the temperature along the seep.

In the winter, groundwater flows out the rock at warmer temperatures than it’s surroundings, making it easily distinguishable. We found that there was a clear relationship between seeps with active groundwater flow and areas of ice growth on the following visit. So, in the winter, if you use an infrared camera to locate where groundwater is flowing on the side of a cliff, you can assume there is a good chance that ice will eventually form at these spots. However, the groundwater did not cool along the rock face, as we had expected it would. This suggests frozen seeps are complex and it is unlikely that temperature pictures can determine the rate of flow of groundwater seeps in the winter.

In the summer, we found that lower flowing seeps did warm up as the water traveled down the rock face, as compared to faster flowing seeps, which did not show as much warming. However, in the 24-hour experiment (where we took infrared pictures every half hour for 24 hours of two seeps), we found that the temperature signature of the seeps changed throughout the day. During the day, there was much more warming of the groundwater as it traveled down the cliff, whereas at night it did not warm as much. This is most likely due to the presence of sunlight and warmer air temperature during the day, which warms the water more as it is traveling down the rock.

In the “artificial seep” experiment, we found that the “seeps” showed more warming than the real seeps. This is probably because we only ran the experiment for 8 hours, so it did not have time to mimic the conditions of real seeps. Also, we noticed that instead of flowing down the rock face, some of the water was actually seeping into the rock, along the breaks in the rock. This may be another reason why the seeps showed more warming, as not enough water was flowing down the rock (instead it was flowing into it).

After completing these experiments, we have concluded several possibilities and limitations for infrared pictures of groundwater seeps.

Possibilities:

  • Locate groundwater seeps in all seasons
  • Locate groundwater seeps in winter and from this, areas of ice growth can be predicted
  • Distinguish between lower flowing seeps and higher flowing seeps in summer (lower flowing seeps have more warming as the water travels down the rock face, higher flowing seeps do not have as much warming)

 Limitations:

  • Need to have a large difference in temperature between the air and groundwater to notice seeps. During the third winter visit, only one seep was identified to be flowing by the infrared camera. However, visual observations showed that eight seeps had groundwater flowing. This is because the temperature of the groundwater was too similar to the temperature of the air, making it not possible to detect the groundwater flow.
  • Groundwater seeps in the winter are complex and do not show a cooling trend, therefore it is unlikely that temperature pictures can determine the rate of flow of groundwater seeps in the winter
  • Breaks in the rock affect the flow of seeps, redirecting the flow, making it hard for temperature pictures to accurately determine flow
  • Sunlight and air temperature affect the “warming” and “cooling” of the groundwater flow, with more warming present during the day and less at night. Focus needs to be on determining the optimal time to use infrared pictures to show the “warming” (or “cooling”) trend.
  • The infrared camera itself has limitations. To use some functions of the camera, you have to correct your data for certain factors (like angle of the camera, humidity, etc.). If you don’t, you won’t be showing accurate data. This limits the amount of things you can do with the infrared camera and must be taken into account in order to ensure the pictures you captured are correct.

 

Despite the large number of limitations, infrared pictures is effective at locating groundwater seeps in all seasons, and able to distinguish between lower flowing seeps and higher flowing seeps (in the summer), which makes this technique a valuable, non-invasive way to study groundwater seepage. Future work should look at determining the optimal time to capture infrared pictures of seeps to determine a relationship between groundwater flow and temperature signatures.

 


 

Making guidelines for graduate students

Making guidelines for graduate students

I strive for effective, compassionate supervision and I clarify my goals, approach and expectations in my guidelines for graduate students (available here, from McGill’s best practices in supervision). As I wrote, most students enter a relationship with a thesis advisor without a clear idea of what they can expect so I compiled this handout to give you some idea of what I expect of you as student and what you can expect of me as an advisor. So that this never happens, I hope:

supervision

My highest level priority is for both of us to communicate and set mutually-agreed-upon goals (LINK OTHER POST) and then both do our best to make those goals into reality. As one of my students, I plan to treat you as a junior colleague who is maturing into a professional engineer or scientist. This means that you can actively co-create opportunities to meet your goals, and also puts a large responsibility on your shoulders to live up to the expectations of performance that are required of a colleague.

I have found clarifying my goals, approach and expectations in my guidelines for graduate students have helped students and helped me be a more effective and compassionate supervisor.


Thank you to the awesome Cutting Edge Workshop for Early Career Geoscience Faculty where I learned about graduate student guidelines a few years ago. I emphatically encourage all young faculty to attend!

A social media dashboard for researchers – taming the digital anarchy for nerds

A social media dashboard for researchers – taming the digital anarchy for nerds

Is anyone else overwhelmed by updating their many webpages, blogs, streams etc?

Jason Priem described the shift from a paper-native academia to a web-native academia, in an excellent article last year in Nature, a shift well beyond the traditional peer-reviewed journal to more diverse outlets of information, interaction and discussion. I am part of the first generation of researchers who are excited to use social media but we need more and better tools to make social media work even better for ourselves and others. Something like HootSuite for Prof 2.0!

I love Hootsuite, a dashboard for managing various social media profiles  (twitter, facebook etc.) in one handy place, across multiple platforms (phone, computer, tablets etc.). It looks something like this…

hootesuiteWe need something similar to manage the various facets of academic life. Just to give you some idea, these are all the pages and sites I try to maintain: personal research webpage, this Water Underground blog, twitter, LinkedIn profile, Google scholar, ResearchGate, ResearcherID, Vimeo, Groundwater footprint. I am happy to do this but it can be overwhelming in the midst of the other pulls of academic life – and I don’t even use facebook!

Ideally, this new platform would be a simple, user-friendly, open-source dashboard that would integrate various social media outlets academics use, plus be a simple place to update citations. A great and relatively simple first step would be a single place to update reference lists, which are a crucial part of how academics are evaluated so it is useful to keep them updated. Currently, my references are listed on Google Scholar, ResearchGate, ResearcherID, as well as a couple university webpages. It would be great to be able to export citations (already in standard formats like EndNote or BibTeX) and have these citations populate and update all my reference lists. I know Google Scholar already does this automatically (and usually correctly) but it would be great for consistency across outlets.

It would be great to link all kinds of altmetrics with this simple, social professor dashboard. Altmetrics are alternative metrics to the widely-used journal impact factor and personal citation indices like the h-index. An aggregate metric is calculated from how much as article, person, event (or blog post – subtle hint!) is viewed, discussed, saved, cited or recommended. As Priem writes, altmetrics will “draw new maps of scholarly contribution, unprecedented in subtlety, texture and detail.” And I find this to be already true – I often follow meandering altmetrics paths from a scientific article to news articles or discussions about the scientific article, and then I use this to enrich blog posts or tweets.

I flit across the web throughout my day and week – this dashboard would help me stay grounded and organized on the web. When I publish a new article, I would automatically update it in the various the places listing my citations, then write a quick tweet about it, check for news articles about it etc. Or I may see a comment on LinkedIn about a scientific article that could be useful for a paper I am writing. The comment in one column of the dashboard would be linked to the article, and the PDF posted on ResearchGate may be in another column of the dashboard. I take the PDF, export the citation to my library and pop it into the paper I am working on, in a series of smooth, integrated steps.

This HootSuite for Prof 2.0 could be a simple tool to enable the shift from a paper-native academia to a web-native academia by leveraging and extending information, interaction and discussion.

Originally published in University Affairs Careers Cafe.